无线通信文献翻译汇总

合集下载

外文参考文献翻译-中文

外⽂参考⽂献翻译-中⽂基于4G LTE技术的⾼速铁路移动通信系统KS Solanki教授，Kratika ChouhanUjjain⼯程学院，印度Madhya Pradesh的Ujjain摘要：随着时间发展，⾼速铁路（HSR）要求可靠的，安全的列车运⾏和乘客通信。

为了实现这个⽬标，HSR的系统需要更⾼的带宽和更短的响应时间，⽽且HSR的旧技术需要进⾏发展，开发新技术，改进现有的架构和控制成本。

为了满⾜这⼀要求，HSR采⽤了GSM的演进GSM-R技术，但它并不能满⾜客户的需求。

因此采⽤了新技术LTE-R，它提供了更⾼的带宽，并且在⾼速下提供了更⾼的客户满意度。

本⽂介绍了LTE-R，给出GSM-R与LTE-R之间的⽐较结果，并描述了在⾼速下哪种铁路移动通信系统更好。

关键词：⾼速铁路，LTE，GSM，通信和信令系统⼀介绍⾼速铁路需要提⾼对移动通信系统的要求。

随着这种改进，其⽹络架构和硬件设备必须适应⾼达500公⾥/⼩时的列车速度。

HSR还需要快速切换功能。

因此，为了解决这些问题，HSR 需要⼀种名为LTE-R的新技术，基于LTE-R的HSR提供⾼数据传输速率，更⾼带宽和低延迟。

LTE-R能够处理⽇益增长的业务量，确保乘客安全并提供实时多媒体信息。

随着列车速度的不断提⾼，可靠的宽带通信系统对于⾼铁移动通信⾄关重要。

HSR的应⽤服务质量（QOS）测量，包括如数据速率，误码率（BER）和传输延迟。

为了实现HSR的运营需求，需要⼀个能够与 LTE保持⼀致的能⼒的新系统，提供新的业务，但仍能够与GSM-R长时间共存。

HSR系统选择合适的⽆线通信系统时，需要考虑性能，服务，属性，频段和⼯业⽀持等问题。

4G LTE系统与第三代（3G）系统相⽐，它具有简单的扁平架构，⾼数据速率和低延迟。

在LTE的性能和成熟度⽔平上，LTE- railway（LTE-R）将可能成为下⼀代HSR通信系统。

⼆ LTE-R系统描述考虑LTE-R的频率和频谱使⽤，对为⾼速铁路（HSR）通信提供更⾼效的数据传输⾮常重要。

通信技术类英文文献

通信技术类英文文献以下是一篇通信技术类英文文献，供参考：Title: 5G Wireless Communication: The Future of Communication TechnologyAbstract: The fifth-generation (5G) wireless communication is the next-generation technology, which is 100 times faster than the 4G technology and provides a higher bandwidth, low latency, and more reliable and secure communication. The 5G wireless communication aims to provide the flexibility of different services, including multimedia, cloud computing, internet of things (IoT), and virtual reality (VR). This paper provides an overview of the5G wireless communication technology, including its features, architecture, and its applications.Introduction: The rapid growth of wireless communication technology has brought significant changes in the way people interact with each other. The 5G wireless communication technology is the revolutionary technology that aims to provide a higher level of communication, which is 100 times faster than the 4G technology. The 5G wireless communication is expected to be the future of communication technology, which will change the way people interact with each other.Features of 5G Wireless Communication:The 5G wireless communication has various features that provide a higher level of communication. These features are:1. High Bandwidth: The 5G wireless communication provides a high bandwidth, which increases the data transfer rate. This high bandwidth provides a better experience for multimedia services, such as streaming video, music, and gaming.2. Low Latency: The 5G wireless communication provides a lower latency, which improves the response time of the communication. This low latency is ideal for real-time applications such as autonomous vehicles, AR/VR, and remote surgeries.3. Massive IoT: The 5G wireless communication supports a large number of IoT devices with a higher density of devices per unit area. This feature enables the functionality of IoT applications in various industries, such as smart homes, smart cities, and healthcare.4. Network Slicing: The 5G wireless communication provides network slicing, which enables the partitioning of the network into multiple virtual networks. This feature provides the flexibility to provide different services with different requirements such as high speed, low latency, and high reliability.5. Security: The 5G wireless communication provides a higher level of security for communication. This security is provided through various features such as authentication, encryption, and privacy.Architecture of 5G Wireless Communication:The 5G wireless communication has a different architecture thanthe previous generations of wireless communication technology. The architecture of the 5G wireless communication is divided into three layers: the user plane, the control plane, and the management plane.1. User Plane: The user plane is responsible for the transmission and reception of user data. This layer involves the transmission and reception of user data through the radio access network (RAN) and the core network.2. Control Plane: The control plane is responsible for controlling the signaling messages between the user equipment (UE) and the network. This layer involves the control of signaling messages related to call setup, call tear down, and mobility management.3. Management Plane: The management plane is responsible for the management of the network resources and the configuration of the network. This layer includes the management of the network functions such as orchestration, automation, and telemetry.Applications of 5G Wireless Communication:The 5G wireless communication has various applications, which will have a significant impact on different industries. Some of the applications are:1. Smart City: The 5G wireless communication enables the functionality of smart city applications such as smart transport, smart parking, and smart street lighting.2. Healthcare: The 5G wireless communication provides a higher level of healthcare with the use of various applications such as telemedicine, remote surgery, and health monitoring.3. Industrial Internet of Things (IIoT): The 5G wireless communication enables the functionality of IIoT applications such as predictive maintenance, asset tracking, and real-time manufacturing process monitoring.4. Agriculture: The 5G wireless communication provides the functionality of precision agriculture applications such as intelligent irrigation, crop monitoring, and farm automation.Conclusion:The 5G wireless communication is the next-generation technology, which is expected to be the future of communication technology. The 5G wireless communication provides a higher level of communication with its features such as high bandwidth, low latency, and massive IoT. The implementation of the 5G wireless communication will have a significant impact on different industries such as healthcare, smart city, and IIoT.。

通信外文翻译外文文献英文文献及译文

通信外文翻译外文文献英文文献及译文Communication SystemA generalized communication system has the following components:(a) Information Source. This produces a message which may be written or spoken words, or some form of data.(b) Transmitter. The transmitter converts the message into a signal, the form of which is suitable for transmission over the communication channel.(c) Communication Channel. The communication channel is the medium used transmit the signal, from the transmitter to the receiver. The channel may be a radio link or a direct wire connection.(d) Receiver. The receiver can be thought of as the inverse of the transmitter. Itchanges the received signal back into a message and passes the message on to its destination which may be a loudspeaker，teleprinter or computer data bank.An unfortunate characteristic of all communication channels is that noise is added to the signal. This unwanted noise may cause distorionsof sound in a telephone, or errors in a telegraph message or data.Frequency Diversion MultiplexingFrequency Diversion Multiplexing(FDM) is a one of analog technologies. A speech signal is 0~3 kHz, single sideband amplitude (SSB) modulation can be used to transfer speech signal to new frequency bands,four similar signals, for example, moved by SSB modulation to share the band from 5 to 20 kHz. The gaps between channels are known as guard spaces and these allow for errors in frequency, inadequate filtering, etc in the engineered system.Once this new baseband signal, a "group" of 4 chEmnels, has been foimed it ismoved around the Lrunk network as a single unit. A hierarchy can be set up withseveral channels fonning a "group". several groups a "supergroup" and several"supergraup" eicher a "nmsrergroup" or "hypergroup".Groups or supergroups are moved around as single units by the communicationsequipment and it is not necessary for the radios to know how many channels are involved. A radio can handle a supergroup provided sufficient bandwidth is available. The size of the groups is a compromise as treating each channel individually involves far more equipment because separate filters, modulators and oscillators are required for every channel rather than for each group. However the failure of one module will lose all of the channels associated with a group.Time Diversion MultiplexingIt is possible, with pulse modulation systems, to use the between samples to transmit signals from other circuits. The technique is knownas time diversion multiplexing (TDM). To do this, it is necessary to employ synchronized switches at eachend of the communication links to enable samples to be transmittedin turn, from each of several circuits. Thus several subscribers appear to use the link simultaneously. Although each user only has periodic short time slots, the original analog signalsbetween samples can be reconstituted at the receiver.Pulse Code ModulationIn analog modulation, the signal was used to modulate the amplitude or frequency of a carrier, directly. However, in digital modulation a stream of pulse, representing the original，is created. This stream is then used to modulate a carrier or alternatively is transmitted directly over a cable. Pulse Code Modulation (PCM) is one of the two techniques commonly used.All pulse systems depend on the analog waveform being sampled at regular intervals. The signal created by sampling our analog speech input is known as pulse amplitude modulation. It is not very useful in practice but is used as an intermediate stage towards forming a PCM signal. It will be seen later that most of the advantages of digital modulation come from the transmitted pulses having two levels only, this being known as a binary system. In PCM the height of each sample is converted into a binary number. There are three step in the process of PCM: sampling, quantizing and coding.Optical Fiber CommunicationsCommunication may be broadly defined as the transfer of information from one point to another. When the information is to be conveyed over any distance acommunication system is usually required. Within a communication system the information transfer is frequently achieved by superimposing or modulating the information on to an electromagnetic wave which acts as a carrier for the informationsignal. This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by demodulation. Sophisticated techniques have been developed for this process by using electromagnetic carrier wavesoperating at radio frequencies as well as microwave and millimeter wave frequencies. However，拻 communication?may also be achieved by using an electromagneticcarrier which is selected from the optical range of frequencies.In this case the information source provides an electrical signal to a transmitter comprising an electrical stage which drives an optical source to give modulation of the light-wave carrier. The optical source which provides the electrical-optical conversionmay be either a semiconductor laser or light emitting diode (LED). The transmission medium consists of an optical fiber cable and the receiver consists of an optical detector which drives a further electrical stage and hence provides demodulation optical carrier. Photodiodes (P-N, P-I-N or avalanche) and , in some instances,phototransistor and photoconductors are utilized for the detection of the optical signal and the electrical-optical conversion. Thus there is a requirement for electrical interfacing at either end of the optical link and at present the signal processing is usually performed electrically.The optical carrier may be modulated by using either an analog or digital information signal. Analog modulation involves the variation of the light emitted from the optical source in a continuous manner. With digital modulation, however, discrete changes in the light intensity are obtained (i.e. on-off pulses). Although often simpler to implement, analog modulation with an optical fiber communication system is lessefficient, requiring a far higher signal to noise ratio at the receiver than digital modulation. Also, the linearity needed for analog modulation is not always provided by semiconductor optical source, especially at high modulation frequencies. For thesereasons，analog optical fiber communications link are generally limited to shorter distances and lower bandwidths than digital links.Initially, the input digital signal from the information source is suitably encoded for optical transmission. The laser drive circuit directly modulates the intensity of the semiconductor laser with the encoded digital signal. Hence a digital optical signal is launched into the optical fiber cable. The avalanche photodiode detector (APD) is followed by a fronted-end amplifier and equalizer orfilter to provide gain as well as linear signal processing and noise bandwidth reduction. Finally, the signal obtained isdecoded to give the original digital information.Mobile CommunicationCordless Telephone SystemsCordless telephone system are full duplex communication systems that use radio to connect a portable handset to a dedicated base station，which is then connected to adedicated telephone line with a specific telephone number on the public switched telephone network (PSTN) .In first generation cordless telephone systems5(manufactured in the 1980s), the portable unit communications only to the dedicatedbase unit and only over distances of a few tens of meters.Early cordless telephones operate solely as extension telephones to a transceiver connected to a subscriber line on the PSTN and are primarily for in-home use.Second generation cordless telephones have recently been introduced which allowsubscribers to use their handsets at many outdoor locations within urban centers such as London or Hong Kong. Modern cordless telephones are sometimes combined with paging receivers so that a subscriber may first be paged and then respond to the pageusing the cordless telephone. Cordless telephone systems provide the user with limited range and mobility, as it is usually not possible to maintain a call if the user travels outside the range of the base station. Typical second generation base stations provide coverage ranges up to a few hundred meters.Cellular Telephone SystemA cellular telephone system provides a wireless connection to the PSTN for any user location within the radio range of the system.Cellular systems accommodate alarge number of users over a large geographic area, within a limited frequency spectrum. Cellular radio systems provide high quality service that is often comparable to that of the landline telephone systems. High capacity is achieved by limiting the coverage of each base station transmitter to a small geographic area called a cell so that the same radio channels may be reused by another base station located some distance away. A sophisticated switching technique called a handoff enables a call to proceeduninterrupted when the user moves from one cell to another.A basic cellular system consists of mobile station, base stations and a mobile switching center (MSC). The Mobile Switching Center is sometimes called a mobiletelephone switching office (MTSO), since it is responsible for connecting all mobiles to the PSTN in a cellular system. Each mobilecommunicates via radio with one of the base stations and may be handed-off to any number of base stations throughout the duration of a call. The mobile station contains a transceiver, an antenna, and control circuitry，and may be mounted in a vehicle or used as a portable hand-held unit. Thebase stations consists of several transmitters and receivers which simultaneously handlefull duplex communications and generally have towers which support several transmitting and receiving antennas. The base station serves as a bridge between all mobile users in the cell and connects the simultaneous mobile calls via telephone linesor microwave links to the MSC. The MSC coordinates the activities of all the base stations and connects the entire cellular system to the PSTN. A typical MSC handles 100000 cellular subscribers and 5000 simultaneous conversations at a time, andaccommodates all billing and system maintenance functions, as well. In large cities, several MSCs are used by a single carrier.Broadband CommunicationAs can be inferred from the examples of video phone and HDTV, the evolution offuture communications will be via broadband communication centered around video signals. The associated services make up a diverse set of high-speed and broadbandservices ranging from video services such as video phone，video conferencing，videosurveillance, cable television (CATV) distribution, and HDTV distribution to the high-speed data services such as high-resolution image transmission, high-speed datatransmission, and color facsimile. The means of standardizing these various broadbandcommunication services so that they can be provided in an integrated manner is no other than the broadband integrated services digital network (B-ISDN). Simple put, therefore,the future communications network can be said to be a broadband telecommunicationsystem based on the B-ISDN.For realization of the B-ISDN, the role of several broadband communicationtechnologies is crucial. Fortunately, the remarkable advances in the field of electronics and fiber optics have led to the maturation of broadband communication technologies.As the B-ISDN becomes possible on the optical communication foundation, the relevant manufacturing technologies for light-source and passive devices and for optical fiberhave advanced to considerable levels. Advances in high-speed device and integratedcircuit technologies for broadband signal processing are also worthy of close attention. There has also been notable progress in software, signal processing, and video equipment technologies. Hence, from the technological standpoint, the B-ISDN hasfinally reached a realizable state.On the other, standardization activities associated with broadband communication have been progressing. The Synchronous Optical Network (SONET) standardization centered around the T1 committee eventually bore fmit in the form of the Synchronous Digital Hierarchy (SDH) standards of the International Consultative Committee in Telegraphy and Telephony (CCITT), paving the way for synchronous digital transmission based on optical communication. The standardization activities of the 5integrated services digital network (ISDN), which commenced in early 1980s with the objective of integrating narrowband services, expanded in scope with the inclusion of broadband services, leading to the standardization of the B-ISDN in late1980抯 and establishing the concept of asynchronous transfer mode (ATM)communication in process. In addition, standardization of various video signals is becoming finalized through the cooperation among such organizations as CCITT, the International Radio-communications Consultative Committee (CCIR), and theInternational Standards Organization (ISO), and reference protocols for high-speedpacket communication are being standardized through ISO, CCITT, and the Institute of Electrical and Electronics Engineer (IEEE).Various factors such as these have made broadband communication realizable.5Therefore, the 1990s is the decade in which matured broadband communicationtechnologies will be used in conjunction with broadband standards to realize broadband communication networks. In the broadband communication network, the fiber opticnetwork will represent the physical medium for implementing broadband communication, while synchronous transmission will make possible the transmission of broadband service signals over the optical medium. Also, the B-ISDN will be essentialas the broadband telecommunication network established on the basis of optical medium and synchronous transmission and ATM is the communication means that enables the realization of the B-ISDN. The most important of the broadband services to be providedthrough the B-ISDN are high-speed data communication services and videocommunication services.Image AcquisitionA TV camera is usually used to take instantaneous images and transform them into electrical signals, which will be further translated into binary numbers for the computer to handle. The TV camera scans oneline at a time. Each line is further divided into hundreds of pixels. The whole frame is divided into hundreds (for example, 625) of lines.The brightness of a pixel can be represented by a binary number with certain bits, for example, 8 bits. The value of the binary number varies from 0 to 255, a range great enough to accommodate all possible contrast levels of images taken from real scene.These binary numbers are sorted in an RAM (it must have a great capacity) ready for processing by the computer.Image ProcessingImage processing is for improving the quality of the images obtained. First, it is necessary to improve the signal-to-noise ratio. Here noise refers to any interference flaw or aberation that obscure the objects on the image. Second, it is possible to improve contrast, enhance sharpness of edges between images through various computational means.Image AnalysisIt is for outlining all possible objects that are included in the scene. A computer program checks through the binary visual informationin store for it and identifies specific feature and characteristics of those objects. Edges or boundaries are identifiablebecause of the different brightness levels on either side of them. Usingcertain algorithms, the computer program can outline all possible boundaries of the objects in the scene. Image analysis also looks for textures and shadings between lines.Image ComprehensionImage Comprehension means understanding what is in a scene. Matching the prestored binary visual information with certain templates which represent specific objects in a binary form is technique borrowed from artificial intelligence, commonly referred to as "templeite matching"emplate matching? One by one,the templates are checked against the binary information representing the scene. Once a match occurs, an object is identified. The template matching process continues until all possible objects in the scene have been identified, otherwise it fails.通信系统一般的通信系统由下列部分组成:信源。

通信类英文文献及翻译

附录一、英文原文：Detecting Anomaly Trafﬁc using Flow Data in the realVoIP networkI. INTRODUCTIONRecently, many SIP[3]/RTP[4]-based VoIP applications and services have appeared and their penetration ratio is gradually increasing due to the free or cheap call charge and the easy subscription method. Thus, some of the subscribers to the PSTN service tend to change their home telephone services to VoIP products. For example, companies in Korea such as LG Dacom, Samsung Net- works, and KT have begun to deploy SIP/RTP-based VoIP services. It is reported that more than ﬁve million users have subscribed the commercial VoIP services and 50% of all the users are joined in 2009 in Korea [1]. According to IDC, it is expected that the number of VoIP users in US will increase to 27 millions in 2009 [2]. Hence, as the VoIP service becomes popular, it is not surprising that a lot of VoIP anomaly trafﬁc has been already known [5]. So, Most commercial service such as VoIP services should provide essential security functions regarding privacy, authentication, integrity and non-repudiation for preventing malicious trafﬁc. Particu- larly, most of current SIP/RTP-based VoIP services supply the minimal security function related with authentication. Though secure transport-layer protocols such as Transport Layer Security (TLS) [6] or Secure RTP (SRTP) [7] have been standardized, they have not been fully implemented anddeployed in current VoIP applications because of the overheads of implementation and performance. Thus, un-encrypted VoIP packets could be easily sniffed and forged, especially in wireless LANs. In spite of authentication,the authentication keys such as MD5 in the SIP header could be maliciously exploited, because SIP is a text-based protocol and unencrypted SIP packets are easily decoded. Therefore, VoIP services are very vulnerable to attacks exploiting SIP and RTP. We aim at proposing a VoIP anomaly trafﬁc detection method using the ﬂow-based trafﬁc measurement archi-tecture. We consider three representative VoIP anomalies called CANCEL, BYE Denial of Service (DoS) and RTP ﬂooding attacks in this paper, because we found that malicious users in wireless LAN could easily perform these attacks in the real VoIP network. For monitoring VoIP packets, we employ the IETF IP Flow Information eXport (IPFIX) [9] standard that is based on NetFlow v9. This trafﬁc measurement method provides a ﬂexible and extensible template structure for various protocols, which is useful for observing SIP/RTP ﬂows [10]. In order to capture and export VoIP packets into IPFIX ﬂows, we deﬁne two additional IPFIX templates for SIP and RTP ﬂows. Furthermore, we add four IPFIX ﬁelds to observe packets which are necessary to detect VoIP source spooﬁng attacks in WLANs.II. RELATED WORK[8] proposed a ﬂooding detection method by the Hellinger Distance (HD) concept. In [8], they have pre- sented INVITE, SYN and RTP ﬂooding detection meth-ods. The HD is the difference value between a training data set and a testing data set. The training data set collected trafﬁc over n sampling period of duration Δ testing data set collected trafﬁc next the training data set in the same period. If the HD is close to ‘1’, this testing data set is regarded as anomaly trafﬁc. For using this method, they assumed that initial training data set didnot have any anomaly trafﬁc. Since this method was based on packet counts, it might not easily extended to detect other anomaly trafﬁc except ﬂooding. On the other hand, [11] has proposed a VoIP anomaly trafﬁc detection method using Extended Finite State Machine (EFSM). [11] has suggested INVITE ﬂooding, BYE DoS anomaly trafﬁc and media spamming detection methods. However, the state machine required more memory because it had to maintain each ﬂow. [13] has presented NetFlow-based VoIP anomaly detection methods for INVITE, REGIS-TER, RTP ﬂooding, and REGISTER/INVITE scan. How-ever, the VoIP DoS attacks considered in this paper were not considered. In [14], an IDS approach to detect SIP anomalies was developed, but only simulation results are presented. For monitoring VoIP trafﬁc, SIPFIX [10] has been proposed as an IPFIX extension. The key ideas of the SIPFIX are application-layer inspection and SDP analysis for carrying media session information. Yet, this paper presents only the possibility of applying SIPFIX to DoS anomaly trafﬁc detection and prevention. We described the preliminary idea of detecting VoIP anomaly trafﬁc in [15]. This paper elaborates BYE DoS anomaly trafﬁc and RTP ﬂooding anomaly trafﬁc detec-tion method based on IPFIX. Based on [15], we have considered SIP and RTP anomaly trafﬁc generated in wireless LAN. In this case, it is possible to generate the similiar anomaly trafﬁc with normal VoIP trafﬁc, because attackers can easily extract normal user information from unencrypted VoIP packets. In this paper, we have extended the idea with additional SIP detection methods using information of wireless LAN packets. Furthermore, we have shown the real experiment results at the commercial VoIP network.III. THE VOIP ANOMALY TRAFFIC DETECTION METHOD A. CANCEL DoS Anomaly Trafﬁc DetectionAs the SIP INVITE message is not usually encrypted, attackers could extract ﬁelds necessary to reproduce the forged SIP CANCEL message by snifﬁng SIP INVITE packets, especially in wireless LANs. Thus, we cannot tell the difference between the normal SIP CANCEL message and the replicated one, because the faked CANCEL packet includes the normal ﬁelds inferred from the SIP INVITE message. The attacker will perform the SIP CANCEL DoS attack at the same wireless LAN, because the purpose of the SIP CANCEL attack is to prevent the normal call estab-lishment when a victim is waiting for calls. Therefore, as soon as the attacker catches a call invitation message for a victim, it will send a SIP CANCEL message, which makes the call establishment failed. We have generated faked SIP CANCEL message using sniffed a SIP INVITE in SIP header of this CANCEL message is the same as normal SIP CANCEL message, because the attacker can obtain the SIP header ﬁeld from unencrypted normal SIP message in wireless LAN environment. Therefore it is impossible to detect the CANCEL DoS anomaly trafﬁc using SIP headers, we use the different values of the wireless LAN frame. That is, the sequence number in the frame will tell the difference between a victim host and an attacker. We look into source MAC address and sequence number in the MAC frame including a SIP CANCEL message as shown in Algorithm 1. We compare the source MAC address of SIP CANCEL packets with that of the previously saved SIP INVITE ﬂow. If the source MAC address of a SIP CANCEL ﬂow is changed, it will be highly probable that the CANCEL packet is generated by a unknown user. However, the source MAC address could be spoofed. Regarding source spooﬁng detection, we employ the method in [12] that uses sequence numbers of frames. We calculate the gap between n-th and (n-1)-th frames. As the sequence number ﬁeld in a MAC header uses 12 bits, it varies from 0 to 4095. When we ﬁnd that the sequence number gap between a single SIP ﬂow is greater than the threshold value of N that willbe set from the experiments, we determine that the SIP host address as been spoofed for the anomaly trafﬁc.B. BYE DoS Anomaly Trafﬁc DetectionIn commercial VoIP applications, SIP BYE messages use the same authentication ﬁeld is included in the SIP IN-VITE message for security and accounting purposes. How-ever, attackers can reproduce BYE DoS packets through snifﬁng normal SIP INVITE packets in wireless faked SIP BYE message is same with the normal SIP BYE. Therefore, it is difﬁcult to detect the BYE DoS anomaly trafﬁc using only SIP header snifﬁng SIP INVITE message, the attacker at the same or different subnets could terminate the normal in- progress call, because it could succeed in generating a BYE message to the SIP proxy server. In the SIP BYE attack, it is difﬁcult to distinguish from the normal call termination procedure. That is, we apply the timestamp of RTP trafﬁc for detecting the SIP BYE attack. Generally, after normal call termination, the bi-directional RTP ﬂow is terminated in a bref space of time. However, if the call termination procedure is anomaly, we can observe that a directional RTP media ﬂow is still ongoing, whereas an attacked directional RTP ﬂow is broken. Therefore, in order to detect the SIP BYE attack, we decide that we watch a directional RTP ﬂow for a long time threshold of N sec after SIP BYE message. The threshold of N is also set from the 2 explains the procedure to detect BYE DoS anomal trafﬁc using captured timestamp of the RTP packet. We maintain SIP session information between clients with INVITE and OK messages including the same Call-ID and 4-tuple (source/destination IP Address and port number) of the BYE packet. We set a time threshold value by adding Nsec to the timestamp value of the BYE message. The reason why we use the captured timestamp is that a few RTP packets are observed under second. If RTP trafﬁc is observed after the time threshold, this willbe considered as a BYE DoS attack, because the VoIP session will be terminated with normal BYE messages. C. RTP Anomaly Trafﬁc Detection Algorithm 3 describes an RTP ﬂooding detection method that uses SSRC and sequence numbers of the RTP header. During a single RTP session, typically, the same SSRC value is maintained. If SSRC is changed, it is highly probable that anomaly has occurred. In addition, if there is a big sequence number gap between RTP packets, we determine that anomaly RTP trafﬁc has happened. As inspecting every sequence number for a packet is difﬁcult, we calculate the sequence number gap using the ﬁrst, last, maximum and minimum sequence numbers. In the RTP header, the sequence number ﬁeld uses 16 bits from 0 to 65535. When we observe a wide sequence number gap in our algorithm, we consider it as an RTP ﬂooding attack.IV. PERFORMANCE EVALUATIONA. Experiment EnvironmentIn order to detect VoIP anomaly trafﬁc, we established an experimental environment as ﬁgure 1. In this envi-ronment, we employed two VoIP phones with wireless LANs, one attacker, a wireless access router and an IPFIX ﬂow collector. For the realistic performance evaluation, we directly used one of the working VoIP networks deployed in Korea where an 11-digit telephone number (070-XXXX-XXXX) has been assigned to a SIP wireless SIP phones supporting , we could make calls to/from the PSTN or cellular phones. In the wireless access router, we used two wireless LAN cards- one is to support the AP service, and the other is to monitor packets. Moreover, in order to observe VoIP packets in the wireless access router, we modiﬁed nProbe [16], that is an open IPFIX ﬂow generator, to create and export IPFIX ﬂows related with SIP, RTP, and information. As the IPFIX collector, we have modiﬁed libipﬁx so that it could provide the IPFIX ﬂow decoding function for SIP, RTP, and templates. We used MySQL for the ﬂow DB.B. Experimental ResultsIn order to evaluate our proposed algorithms, we gen-erated 1,946 VoIP calls with two commercial SIP phones and a VoIP anomaly trafﬁc generator. Table I showsour experimental results with precision, recall, and F-score that is the harmonic mean of precision and recall. In CANCEL DoS anomaly trafﬁc detection, our algorithm represented a few false negative cases, which was related with the gap threshold of the sequence number in MAC header. The average of the F-score value for detecting the SIP CANCEL anomaly is %.For BYE anomaly tests, we generated 755 BYE mes-sages including 118 BYE DoS anomalies in the exper-iment. The proposed BYE DoS anomaly trafﬁc detec-tion algorithm found 112 anomalies with the F-score of %. If an RTP ﬂow is terminated before the threshold, we regard the anomaly ﬂow as a normal one. In this algorithm, we extract RTP session information from INVITE and OK or session description messages using the same Call-ID of BYE message. It is possible not to capture those packet, resulting in a few false-negative cases. The RTP ﬂooding anomaly trafﬁc detection experiment for 810 RTP sessions resulted in the F score of 98%.The reason of false-positive cases was related with the sequence number in RTP header. If the sequence number of anomaly trafﬁc is overlapped with the range of the normal trafﬁc, our algorithm will consider it as normal trafﬁc.V. CONCLUSIONSWe have proposed a ﬂow-based anomaly trafﬁc detec-tion method against SIP and RTP-based anomaly trafﬁc in this paper. We presented VoIP anomaly trafﬁc detection methods with ﬂow data on the wireless access router. We used the IETF IPFIX standard to monitor SIP/RTP ﬂows passing through wireless access routers, because its template architecture is easily extensible to several protocols. For this purpose, we deﬁned two new IPFIX templates for SIP and RTP trafﬁc and four new IPFIX ﬁelds for trafﬁc. Using these IPFIX ﬂow templates,we proposed CANCEL/BYE DoS and RTP ﬂooding trafﬁc detection algorithms. From experimental results on the working VoIP network in Korea, we showed that our method is able to detect three representative VoIP attacks on SIP phones. In CANCEL/BYE DoS anomaly trafﬁcdetection method, we employed threshold values about time and sequence number gap for classﬁcation of normal and abnormal VoIP packets. This paper has not been mentioned the test result about suitable threshold values. For the future work, we will show the experimental result about evaluation of the threshold values for our detection method.二、英文翻译：交通流数据检测异常在真实的世界中使用的VoIP网络一 .介绍最近,许多SIP[3],[4]基于服务器的VoIP应用和服务出现了,并逐渐增加他们的穿透比及由于自由和廉价的通话费且极易订阅的方法。

无线通信外文翻译

无线通信外文翻译南京工程学院毕业设计文献资料翻译,原文及译文,原文名称: Wireless Communications课题名称: 无线电子门铃设计学生姓名: 顾玲玲学号: 208080603 指导老师: 马新华所在系部: 通信工程学院专业名称: 电子信息工程2012 年 3 月南京Wireless CommunicationsModern computer technology, industrial revolution, the world economy from the capital into the economy to knowledge economy. Field in the electronic world, fromthstthe 20 century into the era of radio to computer technology in the 21 century as thecenter of the intelligent modern era of electronic systems. Thebasic core of modern electronic systems are embedded computer systems (referred to as embedded systems), while the microcontroller is the most typical and most extensive and most popular embedded systems.Fist, radio has created generations of excellence in the world.thFifties and sixties in the 20 century, the most representative of the advancedelectronic, technology is wireless technology, including radio broadcasting, radio, wireless communications (telegraph) ,Amateur Radio,radio positioning, navigation and other telemetry, remote control, remote technology. Early that these electronic technology led many young people into the wonderful digital world, radio show was a wonderful life, the prospects for science and technology. Electronics began to form a new discipline. Radio electronics, wireless communications began e-world journey. Radio technology not only as a representative of advanced science and technology at that time, but also from popular to professional fields of science, attracting the young people and enable them to find a lot of fun. Ore from the bedside to the superheterodyne radio; report issued from the radio amateur radio stations; from the telephone, electric bell to the radio control model. Became popularyouth radio technology, science and technology education is most popular and most extensive content. So far, many of the older generation of engineer, experts. Professor of the year are radio enthusiasts. Funradio technology, radio technology, components to the radio-based remote control, telemetry, remote electronic systems, has trained several generations of technological excellence.Second, from the popularity of the radio era to era of electronic technology. The early radio technology to promote the development of electronic technology, most notably electronic vacuum tube technology to semiconductor electronic technology, Semiconductor technology to realize the active device miniaturization and low cost, so more popular with radio technology and innovation, and to greatly broaden the number ofnon-radio-control areas. The development of semiconductor technologyleads to the production of integrated circuits. Electronic design engineers1no longer use the discrete electronics components designed circuit modules, and direct selection of integrated circuit componentsconstitute a single system. They freed the design of the circuit unit dedicated to system design, greatly liberating the productive forces of science and technology; promote the wider spread of electronic systems. Semiconductor integrated circuits in the basic digital logic circuits first breakthrough. A large number of digital logic circuits, such as gates, counters, timers, shift registers, and analog switches, comparators, etc., for the electronic digital control provides excellent conditions for the traditional mechanical control to electronic control. Power electronic devices and sensor technology to make the original to the radio as the center of electronic technology turned to mechanical engineering in the field of digital control systems, testing in thefield of information collection, movement of electrical mechanical servo drive control object. Semiconductor and integrated circuit thunit-specific electronic technology a part of. 70 years into the20 century, large scaleintegrated circuit appeared to promote the conventional electronic circuit unit-specific electronic systems development. Many electronic systems unit into a dedicated integrated device such as radios, electronic clocks, calculators, electronic engineers in these areas fromthe circuit, the system designed to debug into the device selection, peripheral device adapter work. Electronic technology, and electronic products enriched, electronic engineers to reduce the difficulty, but at the same time, radio technology, electronic technology has weakened the charm. The development of semiconductor integrated circuits classical electronic systems are maturing, remain in the large scale integrated circuit other than the shrinking of electronic technology, electronic technology is not the old days of radio fun times and comprehensive engineering training.Third, from the classic era of electronic technology to modern electronic technology of the times.th80 years into the 20 century of economic change is most important revolution inthe computer. The computer revolution in the most important sign is the birth of the computer embedded applications. Modern computer numerical requirements should be born. A long period of time is to develop the massive computer numerical duty. But the computer shows the logic operation, processing, control, attracting experts in the filed of electronic control, they want development to meet the control, object requirements of embedded applications computer systems. If you meet the massive data-processing computer system known as general-purpose computer system, then2the system can be the embedded object(such as ships, aircraft, motorcycles, etc.) in a computer system called the embedded computer. Clearly, both the direction of technology development is different. The former requires massive data storage, handling, processing and analysis of high-speed data transmission; while the latter requires reliable operation in the target environment, the external physical parameters on high-speed acquisition, analysis and processing logic and the rapid control of external objects. It will add an early general-purpose computer data acquisition unit, the output driver circuit reluctance to form a heat treatment furnace temperature control system. This general-purpose computer system is not possible for most of the electronic system used, and to make general-purpose computer system meets the requirements of embedded applications, will inevitably affect the development of high-speed numeric processing. In order to solve the contradiction between thethdevelopment of computer of computer technology, in the 20 century 70s.,semiconductor experts another way, in full accordance with the electronic system embedded computer application requirements, a micro-computer’s basic system on achip, the formation of early SCM(single Chip Microcomputer). After the advent of single chip in the computer industry began to appear in the general-purpose computer systems and embedded systems the two branches. Since then, both the embedded system, and general-purposecomputer systems have been developed rapidly. Although the early general-purpose computer converted the embedded system began in the emergence of SCM. Because the microcontroller is designed specifically for embedded applications, the MCU can only achieve embedded applications. MCU embedded applications that best meet environmental requirements, for example, chip-level physical space, large-scale instruction. A computer system microcontroller core embedded electronic systems, intelligent electronic systems for the foundation. Therefore, the current single chip electronic system in widespread use of electronic systems to enable rapid transition to the classical modern intelligent electronic systems.译文无线通信从无线电世界到单片机世界，现代计算机技术的产业革命将世界经济从资本经济带入到知识经济时代。

无线电通信-英汉互译

无线电通信——英汉互译state of the art 技术发展最新水平，当前发展状况，目前发展水平state-of-the-art 最先进的，最新水平的future prospect 未来展望，发展前景wireless communication 无线电通信radar sensing 雷达遥感radiofrequency transceiver functional blockssecondary surveillance radar 二次监视雷达Identification Friend or Foe (IFF) 敌我识别系统system operation 系统操作data fusion 数据融合radar-embedded communicationsUWB (Ultra Wide Band) 超宽带RFID (Radio Frequency Identification Devices) 无线射频识别NASA (National Aeronautics and Space Administration) (美国)国家航空和航天局Space Shuttle Orbiter 轨道飞行器WSN (Wireless Sensor Network) 无线传感网络multifunctional in-situ systemwideband communication 宽带通信combat identification 战斗识别single transceiver systemoperation principle 工作原理duplex mode 双工模式modulation scheme 调制方案signal processing algorithms 信号处理算法frequency division duplex mode 频分双工模式spectra 频谱frequency channel 频道digital circuit 数字电路radio-frequency (RF) 射频front-end circuit 前端电路software-defined radio 软件无线电joint communication 联合通信single-carrier system 单载波系统multi-carrier system 多载波系统frequency domain 频率范围，频域spread spectrum 扩展频谱，OFDM（Orthogonal Frequency Division Multiplexing）正交频分多路复用技术PAPR (Peak-to-Average Power Ratio) 峰值对平均值功率比，峰均功率比Doppler effect 多普勒效应FFT (Fast Fourier Transform) 快速傅里叶变换frequency synchronization 频率同步器CW (Continuous Wave) 连续波AWGN (Additive White Gaussian Noise) 加性高斯白噪声AWGN channel 加性高斯白噪声信道DSSS (Direct Sequence Spread Spectrum) 直接序列扩频THSS (Time Hopping Spread Spectrum) 跳变时间扩频CSS (Chirp Spread Spectrum) 线性调频扩频FMCW (Frequency Modulated Continuous Wave) 调频连续波FSCW (Fractional Slot Concentrated Winding) 分数槽集中绕组ASK (Amplitude Shift Keying) 振幅键控DQPSK (Differential Quadrature Phase Shift Keying) 差分四相相移键控CCK (Complementary Code Keying) 互补码键控BPSK (Binary Phase Shift Keying) 二进制相移键控PAM (Pulse-Amplitude Modulation) 脉幅调制PPM (Pulse Position Modulation) 脉位调制M-PSK (M-ary Phase Shift Keying) 多进制相移键控M-QAM (M-ary quadrature amplitude modulation) 多进制正交振幅调制QPSK (Quaternary Phase Shift Keying) 四相相移键控OOK (On-Off Keying) 开关键控，通断键控FSK（Frequency Shift Keying）移频键控CMOS (Complementary Metal-Oxide-Semiconductor Transistor) 互补金属氧化物半导体。

无线通信外文文献译文

无线通信电机及电子学工程师联合会2005年国际研讨会上关于微波，天线，传播和无线通信的电磁兼容技术在技术发展上的最新动态竹内清一地区10主任东京电机大学摘要本文介绍无线通信技术的最新发展趋势以及组成无线通信技术的四个部分。

第一个也是最重要的发展是全球互联网流量的增长。

在全球互联网流量增长的重要趋势总结在全球地理区域和他们的互联网渗透方面。

第二个部分是实现无线通信所必备的骨干网络中的硬件配套技术的发展。

第三部分是无线通信的中心问题，特别是本地个人用户，第四和最后一个部分是总结发言。

1简介许多技术的发展显然是需要通过无线通信的实现，以满足环保要求的社会背景需要这的种技术发展。

例如，互联网流量每年约增加一倍，而这种快速增长的互联网流量和WWW（全球资讯网）需要为骨干网络配置无线并不一定需要，但对本地无线通信的实现至关重要的巨大带宽。

骨干网主要靠光纤电缆的技术发展以及相关的配套技术配套支持运行的。

这样的等配套技术包括信息处理和WDM（波分复用）和他们使取得的高效无线通信成为了可能。

无线通信，特别是无线互联网特别是无线互联网对于集中，甚至不断移动的短距离范围内的本地个人用户非常重要。

在IEEE 802.11是无线局域网用于与合作媒介访问控制协议的一般原则，也可以扩展到其他类型的无线网络，如无线个人区域网络（WPAN的）。

该服务区的范围变得越来越小，以便让当地个人用户的充分利用无线通讯媒介用于无线互联网流量。

无线通信是无线互联网最便捷的传输介质，这种无线传输介质的有效使用是至关重要的。

可靠的访问几十兆赫可以跨相当大的在其中无线互联网将需要十倍多的细胞的语音系统的地理区域，每个这样的monocles将测量面积小，几十平方米的大约是百分之常规细胞的大小。

它比传统电池可以容纳更多给定的数据速率的有源器件。

为了使这成为可能的，有效的射频频谱空间复用是必要的，从而能够让个人用户访问更贴近低功率的传输点。

对于快速增长的互联网流量的整体通信系统可以由的三个关键的重要领域的技术发展来支持，1）硬件技术需要个人用户的高密度无线传输的实现，2）配套硬件技术的光纤电缆，3）整体通信系统的运作和维护方面的软件技术，我们主要回顾了前两部分的硬件方面2互联网的发展表1显示了最高的互联网普及率最高的24个国家。

通信类英文文献及翻译

姓名：峻霖班级：通信143班学号：2014101108附录一、英文原文：Detecting Anomaly Trafﬁc using Flow Data in thereal VoIP networkI. INTRODUCTIONRecently, many SIP[3]/RTP[4]-based VoIP applications and services have appeared and their penetration ratio is gradually increasing due to the free or cheap call charge and the easy subscription method. Thus, some of the subscribers to the PSTN service tend to change their home telephone services to VoIP products. For example, companies in Korea such as LG Dacom, Samsung Net- works, and KT have begun to deploy SIP/RTP-based VoIP services. It is reported that more than ﬁve million users have subscribed the commercial VoIP services and 50% of all the users are joined in 2009 in Korea [1]. According to IDC, it is expected that the number of VoIP users in US will increase to 27 millions in 2009 [2]. Hence, as the VoIP service becomes popular, it is not surprising that a lot of VoIP anomaly trafﬁc has been already known [5]. So, Most commercial service such as VoIP services should provide essential security functions regarding privacy, authentication, integrity andnon-repudiation for preventing malicious trafﬁc. Particu- larly, most of current SIP/RTP-based VoIP services supply the minimal security function related with authentication. Though secure transport-layer protocols such as Transport Layer Security (TLS) [6] or Secure RTP (SRTP) [7] have been standardized, they have not been fully implemented and deployed in current VoIP applications because of the overheads of implementation and performance. Thus, un-encrypted VoIP packets could be easily sniffed and forged, especially in wireless LANs. In spite of authentication,the authentication keys such as MD5 in the SIP header could be maliciously exploited, because SIP is a text-based protocol and unencrypted SIP packets are easily decoded. Therefore, VoIP services are very vulnerable to attacks exploiting SIP and RTP. We aim at proposing a VoIP anomaly trafﬁc detection method using the ﬂow-based trafﬁc measurement archi-tecture. We consider three representative VoIP anomalies called CANCEL, BYE Denial of Service (DoS) and RTP ﬂooding attacks in this paper, because we found that malicious users in wireless LAN could easily perform these attacks in the real VoIP network. For monitoring VoIP packets, we employ the IETF IP Flow Information eXport (IPFIX) [9] standard that is based on NetFlow v9. This trafﬁc measurement method provides a ﬂexible and extensible template structure for various protocols, which is useful for observing SIP/RTP ﬂows [10]. In order to capture and export VoIP packets into IPFIX ﬂows, we deﬁne two additional IPFIX templates for SIP and RTP ﬂows. Furthermore, weadd four IPFIX ﬁelds to observe 802.11 packets which are necessary to detect VoIP source spooﬁng attacks in WLANs.II. RELATED WORK[8] proposed a ﬂooding detection method by the Hellinger Distance (HD) concept. In [8], they have pre- sented INVITE, SYN and RTP ﬂooding detection meth-ods. The HD is the difference value between a training data set and a testing data set. The training data set collected trafﬁc over n sampling period of duration Δ t.The testing data set collected trafﬁc next the training data set in the same period. If the HD is close to ‘1’, this testing data set is regarded as anomaly trafﬁc. For using this method, they assumed that initial training data set did not have any anomaly trafﬁc. Since this method was based on packet counts, it might not easily extended to detect other anomaly trafﬁc except ﬂooding. On the other hand, [11] has proposed a VoIP anomaly trafﬁc detection method using Extended Finite State Machine (EFSM). [11] has suggested INVITE ﬂooding, BYE DoS anomaly trafﬁc and media spamming detection methods. However, the state machine required more memory because it had to maintain each ﬂow. [13] has presented NetFlow-based VoIP anomaly detection methods for INVITE, REGIS-TER, RTP ﬂooding, and REGISTER/INVITE scan. How-ever, the VoIP DoS attacks considered in this paper were not considered. In [14], an IDS approach to detect SIP anomalies was developed, but only simulation results are presented. For monitoring VoIP trafﬁc, SIPFIX [10] has been proposed as an IPFIX extension. The key ideas of the SIPFIX are application-layer inspection andSDP analysis for carrying media session information. Yet, this paper presents only the possibility of applying SIPFIX to DoS anomaly trafﬁc detection and prevention. We described the preliminary idea of detecting VoIP anomaly trafﬁc in [15]. This paper elaborates BYE DoS anomaly trafﬁc and RTP ﬂooding anomaly trafﬁc detec-tion method based on IPFIX. Based on [15], we have considered SIP and RTP anomaly trafﬁc generated in wireless LAN. In this case, it is possible to generate the similiar anomaly trafﬁc with normal VoIP trafﬁc, because attackers can easily extract normal user information from unencrypted VoIP packets. In this paper, we have extended the idea with additional SIP detection methods using information of wireless LAN packets. Furthermore, we have shown the real experiment results at the commercial VoIP network.III. THE VOIP ANOMALY TRAFFIC DETECTION METHODA. CANCEL DoS Anomaly Trafﬁc DetectionAs the SIP INVITE message is not usually encrypted, attackers could extract ﬁelds necessary to reproduce the forged SIP CANCEL message by snifﬁng SIP INVITE packets, especially in wireless LANs. Thus, we cannot tell the difference between the normal SIP CANCEL message and the replicated one, because the faked CANCEL packet includes the normal ﬁelds inferred from the SIP INVITE message. The attacker will perform the SIP CANCEL DoS attack at the same wireless LAN, because the purpose of the SIP CANCEL attack is to prevent the normal call estab-lishment when a victim is waiting for calls. Therefore, as soonas the attacker catches a call invitation message for a victim, it will send a SIP CANCEL message, which makes the call establishment failed. We have generated faked SIP CANCEL message using sniffed a SIP INVITE message.Fields in SIP header of this CANCEL message is the same as normal SIP CANCEL message, because the attacker can obtain the SIP header ﬁeld from unencrypted normal SIP message in wireless LAN environment. Therefore it is impossible to detect the CANCEL DoS anomaly trafﬁc using SIP headers, we use the different values of the wireless LAN frame. That is, the sequence number in the 802.11 frame will tell the difference between a victim host and an attacker. We look into source MAC address and sequence number in the 802.11 MAC frame including a SIP CANCEL message as shown in Algorithm 1. We compare the source MAC address of SIP CANCEL packets with that of the previously saved SIP INVITE ﬂow. If the source MAC address of a SIP CANCEL ﬂow is changed, it will be highly probable that the CANCEL packet is generated by a unknown user. However, the source MAC address could be spoofed. Regarding 802.11 source spooﬁng detection, we employ the method in [12] that uses sequence numbers of 802.11 frames. We calculate the gap between n-th and (n-1)-th 802.11 frames. As the sequence number ﬁeld in a 802.11 MAC header uses 12 bits, it varies from 0 to 4095. When we ﬁnd that the sequence number gap between a single SIP ﬂow is greater than the threshold value of N that will be set from the experiments, we determine that the SIP host address as been spoofed for the anomaly trafﬁc.B. BYE DoS Anomaly Trafﬁc DetectionIn commercial VoIP applications, SIP BYE messages use the same authentication ﬁeld is included in the SIP IN-VITE message for security and accounting purposes. How-ever, attackers can reproduce BYE DoS packets through snifﬁng normal SIP INVITE packets in wireless LANs.The faked SIP BYE message is same with the normal SIP BYE. Therefore, it is difﬁcult to detect the BYE DoS anomaly trafﬁc using only SIP header information.After snifﬁng SIP INVITE message, the attacker at the same or different subnets could terminate the normal in- progress call, because it could succeed in generating a BYE message to the SIP proxy server. In the SIP BYE attack, it is difﬁcult to distinguish from the normal call termination procedure. That is, we apply the timestamp of RTP trafﬁc for detecting the SIP BYE attack. Generally, after normal call termination, the bi-directional RTP ﬂow is terminated in a bref space of time. However, if the call termination procedure is anomaly, we can observe that a directional RTP media ﬂow is still ongoing, whereas an attacked directional RTP ﬂow is broken. Therefore, in order to detect the SIP BYE attack, we decide that we watch a directional RTP ﬂow for a long time threshold of N sec after SIP BYE message. The threshold of N is also set from the experiments.Algorithm 2 explains the procedure to detect BYE DoS anomal trafﬁc using captured timestamp of the RTP packet. We maintain SIP session information between clients with INVITE and OK messages including the same Call-ID and 4-tuple (source/destination IP Address and port number) of the BYEpacket. We set a time threshold value by adding Nsec to the timestamp value of the BYE message. The reason why we use the captured timestamp is that a few RTP packets are observed under 0.5 second. If RTP trafﬁc is observed after the time threshold, this will be considered as a BYE DoS attack, because the VoIP session will be terminated with normal BYE messages. C. RTP Anomaly Trafﬁc Detection Algorithm 3 describes an RTP ﬂooding detection method that uses SSRC and sequence numbers of the RTP header. During a single RTP session, typically, the same SSRC value is maintained. If SSRC is changed, it is highly probable that anomaly has occurred. In addition, if there is a big sequence number gap between RTP packets, we determine that anomaly RTP trafﬁc has happened. As inspecting every sequence number for a packet is difﬁcult, we calculate the sequence number gap using the ﬁrst, last, maximum and minimum sequence numbers. In the RTP header, the sequence number ﬁeld uses 16 bits from 0 to 65535. When we observe a wide sequence number gap in our algorithm, we consider it as an RTP ﬂooding attack.IV. PERFORMANCE EVALUATIONA. Experiment EnvironmentIn order to detect VoIP anomaly trafﬁc, we established an experimental environment as ﬁgure 1. In this envi-ronment, we employed two VoIP phones with wireless LANs, one attacker, a wireless access router and an IPFIX ﬂow collector. For the realistic performance evaluation, we directly used one of the working VoIP networks deployed in Korea where an 11-digit telephone number (070-XXXX-XXXX) has been assigned to a SIP phone.With wireless SIP phones supporting 802.11, we could make calls to/from the PSTN or cellular phones. In the wireless access router, we used two wireless LAN cards- one is to support the AP service, and the other is to monitor 802.11 packets. Moreover, in order to observe VoIP packets in the wireless access router, we modiﬁed nProbe [16], that is an open IPFIX ﬂow generator, to create and export IPFIX ﬂows related with SIP, RTP, and 802.11 information. As the IPFIX collector, we have modiﬁed libipﬁx so that it could provide the IPFIX ﬂow decoding function for SIP, RTP, and 802.11 templates. We used MySQL for the ﬂow DB.B. Experimental ResultsIn order to evaluate our proposed algorithms, we gen-erated 1,946 VoIP calls with two commercial SIP phones and a VoIP anomaly trafﬁc generator. Table I shows our experimental results with precision, recall, and F-score that is the harmonic mean of precision and recall. In CANCEL DoS anomaly trafﬁc detection, our algorithm represented a few false negative cases, which was related with the gap threshold of the sequence number in 802.11 MAC header. The average of the F-score value for detecting the SIP CANCEL anomaly is 97.69%.For BYE anomaly tests, we generated 755 BYE mes-sages including 118 BYE DoS anomalies in the exper-iment. The proposed BYE DoS anomaly trafﬁc detec-tion algorithm found 112 anomalies with the F-score of 96.13%. If an RTP ﬂow is terminated before the threshold, we regard the anomaly ﬂow as a normal one. In this algorithm, we extract RTP session information from INVITE and OK or session description messages using the same Call-ID of BYE message. It is possible not to capture those packet, resulting in a few false-negative cases. The RTP ﬂooding anomaly trafﬁc detection experiment for 810 RTP sessions resulted in the F score of 98%.The reason of false-positive cases was related with the sequence number in RTP header. If the sequence number of anomaly trafﬁc is overlapped with the range of the normal trafﬁc, our algorithm will consider it as normal trafﬁc.V. CONCLUSIONSWe have proposed a ﬂow-based anomaly trafﬁc detec-tion method against SIP and RTP-based anomaly trafﬁc in this paper. We presented VoIP anomaly trafﬁc detection methods with ﬂow data on the wireless access router. We used the IETF IPFIX standard to monitor SIP/RTP ﬂows passing through wireless access routers, because its template architecture is easily extensible to several protocols. For this purpose, we deﬁned two new IPFIX templates for SIP and RTP trafﬁc and four new IPFIX ﬁelds for 802.11 trafﬁc. Using these IPFIX ﬂow templates,we proposed CANCEL/BYE DoS and RTP ﬂooding trafﬁc detection algorithms. From experimental results on the working VoIP network in Korea, we showed that our method is able to detect three representative VoIP attacks on SIP phones. In CANCEL/BYE DoS anomaly trafﬁcdetection method, we employed threshold values about time and sequence number gap for classﬁcation of normal and abnormal VoIP packets. This paper has not been mentioned the test result about suitable threshold values. For the future work, we will show the experimental result about evaluation of the threshold values for our detection method.二、英文翻译：交通流数据检测异常在真实的世界中使用的VoIP网络一 .介绍最近,多SIP[3],[4]基于服务器的VoIP应用和服务出现了,并逐渐增加他们的穿透比及由于自由和廉价的通话费且极易订阅的法。

蜂窝无线通信系统中英文对照外文翻译文献

中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：RESEARCH OF CELLULAR WIRELESS COMMUNATIONSYSTEMA wide variety of wireless communication systems have been developed to provide access to the communications infrastructure for mobile or fixed users in a myriad of operating environments. Most of today’s wireless systems are based on the cellular radio concept. Cellular communication systems allow a large number of mobile users to seamlessly and simultaneously communicate to wireless modems at fixed base stations using a limited amount of radio frequency (RF) spectrum. The RF transmissions received at the base stations from each mobile are translated to baseband, or to a wideband microwave link, and relayed to mobile switching centers (MSC), which connect the mobile transmissions with the Public Switched Telephone Network (PSTN). Similarly, communications from the PSTN are sent to the base station, where they are transmitted to the mobile. Cellular systems employ eitherfrequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or spatial division multiple access (SDMA) .Wireless communication links experience hostile physical channel characteristics, such as time-varying multipath and shadowing due to large objects in the propagation path. In addition, the performance of wireless cellular systems tends to be limited by interference from other users, and for that reason, it is important to have accurate techniques for modeling interference. These complex channel conditions are difficult to describe with a simple analytical model, although several models do provide analytical tractability with reasonable agreement to measured channel data . However, even when the channel is modeled in an analytically elegant manner, in the vast majority of situations it is still difficult or impossible to construct analytical solutions for link performance when error control coding, equalization, diversity, and network models are factored into the link model. Simulation approaches, therefore, are usually required when analyzing the performance of cellular communication links.Like wireless links, the system performance of a cellular radio system is most effectively modeled using simulation, due to the difficulty in modeling a large number of random events over time and space. These random events, such as the location of users, the number of simultaneous users in the system, the propagation conditions, interference and power level settings of each user, and the traffic demands of each user, combine together to impact the overall performance seen by a typical user in the cellular system. The aforementioned variables are just a small sampling of the many key physical mechanisms that dictate the instantaneous performance of a particular user at any time within the system. The term cellular radio system, therefore, refers to the entire population of mobile users and base stations throughout the geographic service area, as opposed to a single link that connects a single mobile user to a single base station. To design for a particular system-level performance, such as the likelihood of a particular user having acceptable service throughout the system, it is necessary to consider the complexity of multiple users that are simultaneously using the system throughout the coverage area. Thus, simulation is needed to consider the multi-user effects upon any of the individual links between the mobile and the base station.The link performance is a small-scale phenomenon, which deals with the instantaneouschanges in the channel over a small local area, or small time duration, over which the average received power is assumed constant. Such assumptions are sensible in the design of error control codes, equalizers, and other components that serve to mitigate the transient effects created by the channel. However, in order to determine the overall system performance of a large number of users spread over a wide geographic area, it is necessary to incorporate large-scale effects such as the statistical behavior of interference and signal levels experienced by individual users over large distances, while ignoring the transient channel characteristics. One may think of link-level simulation as being a vernier adjustment on the performance of a communication system, and the system-level simulation as being a coarse, yet important, approximation of the overall level of quality that any user could expect at any time.Cellular systems achieve high capacity (e.g., serve a large number of users) by allowing the mobile stations to share, or reuse a communication channel in different regions of the geographic service area. Channel reuse leads to co-channel interference among users sharing the same channel, which is recognized as one of the major limiting factors of performance and capacity of a cellular system. An appropriate understanding of the effects of co-channel interference on the capacity and performance is therefore required when deploying cellular systems, or when analyzing and designing system methodologies that mitigate the undesired effects of co-channel interference. These effects are strongly dependent on system aspects of the communication system, such as the number of users sharing the channel and their locations. Other aspects, more related to the propagation channel, such as path loss, shadow fading (or shadowing), and antenna radiation patterns are also important in the context of system performance, since these effects also vary with the locations of particular users. In this chapter, we will discuss the application of system-level simulation in the analysis of the performance of a cellular communication system under the effects of co-channel interference. We will analyze a simple multiple-user cellular system, including the antenna and propagation effects of a typical system. Despite the simplicity of the example system considered in this chapter, the analysis presented can easily be extended to include other features of a cellular system.2 Cellular Radio SystemSystem-Level Description：Cellular systems provide wireless coverage over a geographic service area by dividing the geographic area into segments called cells as shown in Figure 2-1. The available frequency spectrum is also divided into a number of channels with a group of channels assigned to each cell. Base stations located in each cell are equipped with wireless modems that can communicate with mobile users. Radio frequency channels used in the transmission direction from the base station to the mobile are referred to as forward channels, while channels used in the direction from the mobile to the base station are referred to as reverse channels. The forward and reverse channels together identify a duplex cellular channel. When frequency division duplex (FDD) is used, the forward and reverse channels are split in frequency. Alternatively, when time division duplex (TDD) is used, the forward and reverse channels are on the same frequency, but use different time slots for transmission.Figure 2-1 Basic architecture of a cellular communications system High-capacity cellular systems employ frequency reuse among cells. This requires that co-channel cells (cells sharing the same frequency) are sufficiently far apart from each other to mitigate co-channel interference. Channel reuse is implemented by covering the geographic service area with clusters of N cells, as shown in Figure 2-2, where N is known as the cluster size.Figure 2-2 Cell clustering:Depiction of a three-cell reuse pattern The RF spectrum available for the geographic service area is assigned to each cluster, such that cells within a cluster do not share any channel . If M channels make up the entire spectrum available for the service area, and if the distribution of users is uniform over the service area, then each cell is assigned M/N channels. As the clusters are replicated over the service area, the reuse of channels leads to tiers of co-channel cells, and co-channel interference will result from the propagation of RF energy between co-channel base stations and mobile users. Co-channel interference in a cellular system occurs when, for example, a mobile simultaneously receives signals from the base station in its own cell, as well as from co-channel base stations in nearby cells from adjacent tiers. In this instance, one co-channel forward link (base station to mobile transmission) is the desired signal, and the other co-channel signals received by the mobile form the total co-channel interference at the receiver. The power level of the co-channel interference is closely related to the separation distances among co-channel cells. If we model the cells with a hexagonal shape, as in Figure 2-2, the minimum distance between the center of two co-channel cells, called the reuse distance ND, is（2-1）R3D N Nwhere R is the maximum radius of the cell (the hexagon is inscribed within the radius).Therefore, we can immediately see from Figure 2-2 that a small cluster size (small reuse distance ND), leads to high interference among co-channel cells.The level of co-channel interference received within a given cell is also dependent on the number of active co-channel cells at any instant of time. As mentioned before, co-channel cells are grouped into tiers with respect to a particular cell of interest. The number of co-channel cells in a given tier depends on the tier order and the geometry adopted to represent the shape of a cell (e.g., the coverage area of an individual base station). For the classic hexagonal shape, the closest co-channel cells are located in the first tier and there are six co-channel cells. The second tier consists of 12 co-channel cells, the third, 18, and so on. The total co-channel interference is, therefore, the sum of the co-channel interference signals transmitted from all co-channel cells of all tiers. However, co-channel cells belonging to the first tier have a stronger influence on the total interference, since they are closer to the cell where the interference is measured.Co-channel interference is recognized as one of the major factors that limits the capacity and link quality of a wireless communications system and plays an important role in the tradeoff between system capacity (large-scale system issue) and link quality (small-scale issue). For example, one approach for achieving high capacity (large number of users), without increasing the bandwidth of the RF spectrum allocated to the system, is to reduce the channel reuse distance by reducing the cluster size N of a cellular system . However, reduction in the cluster sizeincreases co-channel interference, which degrades the link quality.The level of interference within a cellular system at any time is random and must be simulated by modeling both the RF propagation environment between cells and the position location of the mobile users. In addition, the traffic statistics of each user and the type of channel allocation scheme at the base stations determine the instantaneous interference level and the capacity of the system.The effects of co-channel interference can be estimated by the signal-tointerference ratio (SIR) of the communication link, defined as the ratio of the power of the desired signal S, to the power of the total interference signal, I. Since both power levels S and I are random variables due to RF propagation effects, user mobility and traffic variation, the SIR is also a random variable. Consequently, the severity of the effects of co-channel interference onsystem performance is frequently analyzed in terms of the system outage probability, defined in this particular case as the probability that SIR is below a given threshold 0S IR . This isdx p ]SIR Pr[SIR P )x 0SIR 0SIR 0outpage （⎰=<= （2-2）Where is the probability density function (pdf) of the SIR. Note the distinction between the definition of a link outage probability, that classifies an outage based on a particular bit error rate (BER) or Eb/N0 threshold for acceptable voice performance, and the system outage probability that considers a particular SIR threshold for acceptable mobile performance of a typical user.Analytical approaches for estimating the outage probability in a cellular system, as discussed in before, require tractable models for the RF propagation effects, user mobility, and traffic variation, in order to obtain an expression for PSIR （x ）. Unfortunately, it is very difficult to use analytical models for these effects, due to their complex relationship to the received signal level. Therefore, the estimation of the outage probability in a cellular system usually relies on simulation, which offers flexibility in the analysis. In this chapter, we present a simple example of a simulation of a cellular communication system, with the emphasis on the system aspects of the communication system, including multi-user performance, traffic engineering, and channel reuse. In order to conduct a system-level simulation, a number of aspects of the individual communication links must be considered. These include the channel model, the antenna radiation pattern, and the relationship between Eb/N0 (e.g., the SIR) and the acceptable performance.SIR(x)p翻译：蜂窝无线通信系统的研究摘要蜂窝通信系统允许大量移动用户无缝地、同时地利用有限的射频（radio frequency，RF）频谱与固定基站中的无线调制解调器通信。

无线通信外文翻译

附件1：外文资料翻译译文7．mimo：空间多路复用与信道建模本书我们已经看到多天线在无线通信中的几种不同应用。

在第3章中，多天线用于提供分集增益，增益无线链路的可靠性，并同时研究了接受分解和发射分解，而且，接受天线还能提供功率增益。

在第5章中，我们看到了如果发射机已知信道，那么多采用多幅发射天线通过发射波束成形还可以提供功率增益。

在第6章中，多副发射天线用于生产信道波动，满足机会通信技术的需要，改方案可以解释为机会波束成形，同时也能够提供功率增益。

这章以及接下来的几章将研究一种利用多天线的新方法。

我们将会看到在合适的信道衰落条件下，同时采用多幅发射天线和多幅接收天线可以提供用于通信的额外的空间维数并产生自由度增益，利用这些额外的自由度可以将若干数据流在空间上多路复用至MIMO 信道中，从而带来容量的增加：采用n副发射天线和接受天线的这类MIMO信道的容量正比于n。

过去一度认为在基站采用多幅天线的多址接入系统允许若干个用户同时与基站通信，多幅天线可以实现不同用户信号的空间隔离。

20世纪90年代中期，研究人员发现采用多幅发射天线和接收天线的点对点信道也会出现类似的效应，即使当发射天线相距不远时也是如此。

只要散射环境足够丰富，使得接受天线能够将来自不同发射天线的信号分离开，该结论就成立。

我们已经了解到了机会通信技术如何利用信道衰落，本章还会看到信道衰落对通信有益的另一例子。

将机会通信与MIMO技术提供的性能增益的本质进行比较和对比是非常的有远见的。

机会通信技术主要提供功率增益，改功率增益在功率受限系统的低信噪比情况下相当明显，但在宽带受限系统的高信噪比情况下则很不明显。

正如我们将看到的，MIMO技术不仅能够提供功率增益，还可以提供自由度增益，因此，MIMO技术成为在高信噪比情况下大幅度增加容量的主要工具。

MIMO通信是一个内容非常丰富的主题，对它的研究将覆盖本书其余章节。

本章集中研究能够实现空间多路复用的物理环境的属性，并阐明如何在MIMO统计信道模型中简明扼要地俘获这些属性。

中文翻译Wireless+communications(无线通信)5-10页

1.3 Technical IssuesMany technical challenges must be addressed to enable the wireless applications of the future. These challenges extend across all aspects of the system design. As wireless terminals add more features, these small devices must incorporate multiple modes of operation to support the different applications and media. Computers process voice, image, text, and video data, but breakthroughs in circuit design are required to implement the same multimode operation in a cheap, lightweight, handhe ld device. Since consumers don’t want large batteries that frequently need recharging, transmission and signal processing in the portable terminal must consume minimal power. The signal processing required to support multimedia applications and networking functions can be power-intensive. Thus, wireless infrastructure-based networks, such as wireless LANs and cellular systems, place as much of the processing burden as possible on ﬁxed sites with large power resources. The associated bottlenecks and single points-of-failure are clearly undesirable for the overall system. Ad hoc wireless networks without infrastructure are highly appealing for many ap plications due to their ﬂexibility and robustness. For these networks all processing and control must be performed by the network nodes in a distributed fashion, making energy-efﬁciency challenging to achieve. Energy is a particularly critical resource in networks where nodes cannot recharge their batteries, for example in sensing applications. Network design to meet the application requirements under such hard energy constraints remains a big technological hurdle. The ﬁnite bandwidth and random variations of wireless channels also requires robust applications that degrade gracefully as network performance degrades.Design of wireless networks differs fundamentally from wired network design due to the nature of the wireless channel. This channel is an unpred ictable and difﬁcult communications medium. First of all, the radio spectrum is a scarce resource that must be allocated to many different applications and systems. For this reason spectrum is controlled by regulatory bodies both regionally and globally. A regional or global system operating in a given frequency band must obey the restrictions for that band set forth by the corresponding regulatory body. Spectrum can also be very expensive since in many countries spectral licenses are often auctioned to the highest bidder. In the U.S. companies spent over nine billion dollars for second generation cellular licenses, and the auctions in Europe for third generation cellular spectrum garnered around 100 billion dollars. The spectrum obtained through these aucti ons must be used extremely efﬁciently to get a reasonable return on its investment, and it must also be reused over and over in the same geographical area, thus requiring cellular system designs with high capacity and good performance. At frequencies around several Gigahertz wireless radio components with reasonable size, power consumption, and cost are available. However, the spectrum in this frequency range is extremely crowded. Thus, technological breakthroughs to enable higher frequency systems with the same cost and performance would greatly reduce the spectrum shortage. However, path loss at these higher frequencies is larger, thereby limiting range, unless directional antennas are used.As a signal propagates through a wireless channel, it experiences randomﬂuctuations in time if the transmitter, receiver, or surrounding objects are moving, due to changing reﬂections and attenuation. Thus, the characteristics of the channel appear to change randomly with time, which makes it difﬁcult to design reliable systems with guaranteed performance. Security is also more difﬁcult to implement in wireless systems, since the airwaves are susceptible to snooping from anyone with an RF antenna. The analog cellular systems have no security, and one can easily listen in on conversations by scanning the analog cellular frequency band. All digital cellularsystems implement some level of encryption. However, with enough knowledge, time and determination most of these encryption methods can be cracked and, indeed, several have been compromised. To support applications like electronic commerce and credit card transactions, the wireless network must be secure against such listeners.W ireless networking is also a signiﬁcant challenge. The network must be able to locate a given user wherever it is among billions of globally-distributed mobile terminals. It must then route a call to that user as it moves at speeds of up to 100 Km/hr. The ﬁnite resources of the network must be allocated in a fair and efﬁcient manner relative to changing user demands and locations. Moreover, there currently exists a tremendous infrastructure of wired networks: the telephone system, the Internet, and ﬁber opt ic cable, which should be used to connect wireless systems together into a global network. However, wireless systems with mobile users will never be able to compete with wired systems in terms of data rates and reliability. Interfacing between wireless and wired networks with vastly different performance capabilities is a difﬁcult problem.Perhaps the most signiﬁcant technical challenge in wireless network design is an overhaul of the design process itself. Wired networks are mostly designed according to a layered approach, whereby protocols associated with different layers of the system operation are designed in isolation, with baseline mechanisms to interface between layers. The layers in a wireless systems include the link or physical layer, which handles bit transmissions over the communications medium, the access layer, which handles shared access to the communications medium,the network and transport layers, which routes data across the network and insure end-to-end connectivity and data delivery, and the application layer, which dictates the end-to-end data rates and delay constraints associated with the application. While a layering methodology reduces complexity and facilitates modularity and standardization, it also leads to inefﬁciency and performance loss due to the lack of a global design optimization. The large capacity and good reliability of wired networks make these inefﬁciencies relatively benign for many wired network applications, although it does preclude good performance of delay-constrained applications such as voice and video. The situation is very different in a wireless network. Wireless links can exhibit very poor performance, and this performance along with user connectivity and network topology changes over time. In fact, the very notion of a wireless link is somewhat fuzzy due to the nature of radio propagation and broadcasting. The dynamic nature and poor performance of the underlying wireless communication channel indicates that high-performance networks must be optimized for this channel and must be robust and adaptive to its variations, as well as to network dynamics. Thus, these networks require integrated and adaptive protocols at all layers, from the link layer to the application layer. This cross-layer protocol design requires interdiciplinary expertise in communications, signal processing, and network theory and design.In the next section we give an overview of the wireless systems in operation today. It will be clear from this overview that the wireless vision remains a distant goal, with many technical challenges to overcome. These challenges will be examined in detail throughout the book.1.4 CurrentWireless SystemsThis section provides a brief overview of current wireless systems in operation today. The design details of these system are constantly evolving, with new systems emerging and old ones going by the wayside. Thus, we will focus mainly on the high-level design aspects of the most common systems. More details on wireless system standards can be found in [1, 2, 3] A summary of the main wireless system standards is given in Appendix D.1.4.1 Cellular Telephone SystemsCellular telephone systems are extremely popular and lucrative worldwide: these are the systems that ignited the wireless revolution. Cellular systems provide two-way voice and data communication with regional, national, or international coverage. Cellular systems were initially designed for mobile terminals inside vehicles with antennas mounted on the vehicle roof. Today these systems have evolved to support lightweight handheld mobile terminals operating inside and outside buildings at both pedestrian and vehicle speeds.The basic premise behind cellular system design is frequency reuse, which exploits the fact that signal power falls off with distance to reuse the same frequency spectrum at spatially-separated locations. Speciﬁcally, the coverage area of a cellular system is divided into nonoverlapping cells where some set of channels is assigned to each cell. This same channel set is used in another cell some distance away, as shown in Figure 1.1, where Ci denotes the channel set used in a particular cell. Operation within a cell is controlled by a centralized base station, as described in more detail below. The interference caused by users in different cells operating on the same channel set is called intercell interference. The spatial separation of cells that reuse the same channel set, the reuse distance, should be as small as possible so that frequencies are reused as often as possible, thereby maximizing spectral efﬁciency. However, as the reuse distance decreases, intercell interference increases, due to the smaller propagation distance between interfering cells. Since intercell interference must remain below a given threshold for acceptable system performance, reuse distance cannot be reduced below some minimum value. In practice it is quite difﬁcult to determine this minimum value since both the transmitting and interfering signals experience random power variations due to the characteristics of wireless signal propagation. In order to determine the best reuse distance and base station placement, an accurate characterization of signal propagation within the cells is needed.Initial cellular system designs were mainly driven by the high cost of base stations, approximately one million dollars apiece. For this reason early cellular systems used a relatively small number of cells to cover an entire city or region. The cell base stations were placed on tall buildings or mountains and transmitted at very high power with cell coverage areas of several square miles. These large cells are called macrocells. Signal power was radiated uniformly in all directions, so a mobile moving in a circle around the base station would have approximately constant received power if the signal was not blocked by an attenuating object. This circular contour of constant power yields a hexagonal cell shape for the system, since a hexagon is the closest shape to a circle that can cover a given area with multiple nonoverlapping cells.Cellular systems in urban areas now mostly use smaller cells with base stations close to street level transmitting at much lower power. These smaller cells are called microcells or picocells, depending on their size. This evolution to smaller cells occured for two reasons: the need for higher capacity in areas with high user density and the reduced size and cost of base station electronics. A cell of any size can support roughly the same number of users if the system is scaled accordingly. Thus, for a given coverage area a system with many microcells has a higher number of users per unit area than a system with just a few macrocells. In addition, less power is required at the mobile terminals in microcellular systems, since the terminals are closer to the base stations. However, the evolution to smaller cells has complicated network design. Mobiles traverse a small cell more quickly than a large cell, and therefore handoffs must be processed more quickly. In addition, location management becomes more complicated, since there are more cells within agiven area where a mobile may be located. It is also harder to develop general propagation models for small cells, since signal propagation in these cells is highly dependent on base station placement and the geometry of the surrounding reﬂectors. In particular, a hexagonal cell shape is generally not a good approximation to signal propagation in microcells. Microcellular systems are often designed using square or triangular cell shapes, but these shapes have a large margin of error in their approximation to microcell signal propagation [9].All base stations in a given geographical area are connected via a high-speed communications link to a mobile telephone switching ofﬁce (MTSO), as shown in Figure 1.2. TheMTSO acts as a central controller for the network, allocating channels within each cell, coordinating handoffs between cells when a mobile traverses a cell boundary, and routing calls to and from mobile users. The MTSO can route voice calls through the public switched telephone network (PSTN) or provide Internet access. A new user located in a given cell requests a channel by sending a call request to the cell’s base station over a separate control channel. The request is relayed to theMTSO, which accepts the call request if a channel is available in that cell. If no channels are available then the call request is rejected. A call handoff is initiated when the base station or the mobile in a given cell detects that the received signal power for that call is approaching a given minimum threshold. In this case the base station informs theMTSO that the mobile requires a handoff, and the MTSO then queries surrounding base stations to determine if one of these stations can detect that mobile’s signal. If so then the MTSO co ordinates a handoff between the original base station and the new base station. If no channels are available in the cell with the new base station then the handoff fails and the call is terminated. A call will also be dropped if the signal strength between a mobile and its base station drops below the minimum threshold needed for communication due to random signal variations.The ﬁrst generation of cellular systems used analog communications, since they were primarily designed in the 1960’s, before digital communications became prevalent. Second generation systems moved from analog to digital due to its many advantages. The components are cheaper, faster, smaller, and require less power. V oice quality is improved due to error correction coding. Digital systems also have higher capacity than analog systems since they can use more spectrally-efﬁcient digital modulation and more efﬁcient techniques to share the cellular spectrum. They can also take advantage of advanced compression techniques and voice activity factors. In addition, encryption techniques can be used to secure digital signals against eavesdropping. Digital systems can also offer data services in addition to voice, including short messaging, email, Internet access, and imaging capabilities (camera phones). Due to their lower cost and higher efﬁciency, service providers used aggressive pricing tactics to encourage user migration from analog to digital systems, and today analog systems are primarily used in areas with no digital service. However, digital systems do not always work as well as the analog ones. Users can experience poor voice quality, frequent call dropping, and spotty coverage in certain areas. System performance has certainly improved as the technology and networks mature. In some areas cellular phones provide almost the same quality as landline service. Indeed, some people have replaced their wireline telephone service inside the home with cellular service.Spectral sharing in communication systems, also called multiple access, is done by dividing the signaling dimensions along the time, frequency, and/or code space axes. In frequency-division multiple access (FDMA) the total system bandwidth is divided into orthogonal frequency channels. In time-division multiple access (TDMA) time is divided orthogonally and each channel occupiesthe entire frequency band over its assigned timeslot. TDMA is more difﬁcult to implement than FDMA since the users must be time-synchronized. However, it is easier to accommodate multiple data rates with TDMA since multiple timeslots can be assigned to a given user. Code-division multiple access (CDMA) is typically implemented using direct-sequence or frequency-hopping spread spectrum with either orthogonal or non-orthogonal codes. In direct-sequence each user modulates its data sequence by a different chip sequence which is much faster than the data sequence. In the frequency domain, the narrowband data signal is convolved with the wideband chip signal, resulting in a signal with a much wider bandwidth than the original data signal. In frequency-hopping the carrier frequency used to modulate the narrowband data signal is varied by a chip sequence which may be faster or slower than the data sequence. This results in a modulated signal that hops over different carrier frequencies. Typically spread spectrum signals are superimposed onto each other within the same signal bandwidth. A spread spectrum receiver separates out each of the distinct signals by separately decoding each spreading sequence. However, for non-orthogonal codes users within a cell interfere with each other (intracell interference) and codes that are reused in other cells cause intercell interference. Both the intracell and intercell interference power is reduced by the spreading gain of the code. Moreover, interference in spread spectrum systems can be further reduced through multiuser detection and interference cancellation. More details on these different techniques for spectrum sharing and their performance analysis will be given in Chapters 13-14. The design tradeoffs associated with spectrum sharing are very complex, and the decision of which technique is best for a given system and operating environment is never straightforward.Efﬁcient cellular system designs are interference-limited, i.e. the interference dominates the noise ﬂoor since otherwise more users could be added to the system. As a result, any technique to reduce interference in cellular systems leads directly to an increase in system capacity and performance. Some methods for interference reduction in use today or proposed for future systems include cell sectorization, directional and smart antennas, multiuser detection, and dynamic resource allocation. Details of these techniques will be given in Chapter 15.The ﬁrst generation (1G) cellular systems in the U.S., called the Advance Mobile Phone Service (AMPS), used FDMA with 30 KHz FM-modulated voice channels. The FCC initially allocated 40 MHz of spectrum to this system, which was increased to 50 MHz shortly after service introduction to support more users. This total bandwidth was divided into two 25 MHz bands, one for mobile-to-base station channels and the other for base station-to-mobile channels. The FCC divided these channels into two sets that were assigned to two different service providers in each city to encourage competition. A similar system, the European Total Access Communication System (ETACS), emerged in Europe. AMPS was deployed worldwide in the 1980’s and remains the only cellular service in some of these areas, including some rural parts of the U.S.Many of the ﬁrst generation cellular systems in Europe were incompatible, and the Europeans quickly converged on a uniform standard for second generation (2G) digital systems called GSM 1. The GSM standard uses a combination of TDMA and slow frequency hopping with frequency-shift keying for the voice modulation. In contrast, the standards activities in the U.S. surrounding the second generation of digital cellular provoked a raging debate on spectrum sharing techniques, resulting in several incompatible standards [10, 11, 12]. In particular, there are two standards in the 900 MHz cellular frequency band: IS-54, which uses a combination of TDMA and FDMA and phase-shift keyed modulation, and IS-95, which uses direct-sequenceCDMA with binary modulation and coding [13, 14]. The spectrum for digital cellular in the 2 GHz PCS frequency band was auctioned off, so service providers could use an existing standard or develop proprietary systems for their purchased spectrum. The end result has been three different digital cellular standards for this frequency band: IS-136 (which is basically the same as IS-54 at a higher frequency), IS-95, and the European GSM standard. The digital cellular standard in Japan is similar to IS-54 and IS-136 but in a different frequency band, and the GSM system in Europe is at a different frequency than the GSM systems in the U.S. This proliferation of incompatible standards in the U.S. and internationally makes it impossible to roam between systems nationwide or globally without a multi-mode phone and/or multiple phones (and phone numbers).All of the second generation digital cellular standards have been enhanced to support high rate packet data services [15]. GSM systems provide data rates of up to 100 Kbps by aggregating all timeslots together for a single user. This enhancement is called GPRS. A more fundamental enhancement, Enhanced Data Services for GSM Evolution (EDGE), further increases data rates using a high-level modulation format combined with FEC coding. This modulation is more sensitive to fading effects, and EDGE uses adaptive techniques to mitigate this problem.Speciﬁcally, EDGE deﬁnes six different modulation and coding combinations, each optimized to a different value of received SNR. The received SNR is measured at the receiver and fed back to the transmitter, and the best modulation and coding combination for this SNR value is used. The IS-54 and IS-136 systems currently provide data rates of 40-60 Kbps by aggregating time slots and using high-level modulation. This evolution of the IS-136 standard is called IS-136HS (high-speed). The IS-95 systems support higher data using a time-division technique called high data rate (HDR)[16].The third generation (3G) cellular systems are based on a wideband CDMA standard developed within the auspices of the International Telecommunications Union (ITU) [15]. The standard, initially called International Mobile Telecommunications 2000 (IMT-2000), provides different data rates depending on mobility and location, from 384 Kbps for pedestrian use to 144 Kbps for vehicular use to 2 Mbps for indoor ofﬁce use. The 3G standard is incompatible with 2G systems, so service providers must invest in a new infrastructure before they can provide 3G service. The ﬁrst 3G systems were deployed in Japan. One reason that 3G services came out ﬁrst in Japan is the process of 3G spectrum allocation, which in Japan was awarded without much up-front cost. The 3G spectrum in both Europe and the U.S. is allocated based on auctioning, thereby requiring a huge initial investment for any company wishing to provide 3G service. European companies collectively paid over 100 billion dollars in their 3G spectrum auctions. There has been much controversy over the 3G auction process in Europe, with companies charging that the nature of the auctions caused enormous overbidding and that it will be very difﬁcult if not impossible to reap a proﬁt on this spectrum. A few of the companies have already decided to write off their investment in 3G spectrum and not pursue system buildout. In fact 3G systems have not grown as anticipated in Europe, and it appears that data enhancements to 2G systems may sufﬁce to satisfy user demands. However,the 2G spectrum in Europe is severely overcrowded, so users will either eventually migrate to 3G or regulations will change so that 3G bandwidth can be used for 2G services (which is not currently allowed in Europe). 3G development in the U.S. has lagged far behind that of Europe. The available 3G spectrum in the U.S. is only about half that available in Europe. Due to wrangling about which parts of the spectrum will be used, the 3G spectral auctions in the U.S. have not yet taken place. However, theU.S. does allow the 1G and 2G spectrum to be used for 3G, and this ﬂexibility may allow a more gradual rollout and investment than the more restrictive 3G requirements in Europe. It appears that delaying 3G in the U.S. will allow U.S. service providers to learn from the mistakes andsuccesses in Europe and Japan.。

通信论文英文翻译

论文附件一、英文原文：Introduction to Wireless Communication SystemsThe ability to communicate with people on the move has evolved remarkably since Guglielmo Marconi first radio's ability to provide continuous contact with ships sailing the English channel. That was in 1897, and since then new wireless communications methods and services have been enthusiastically adopted by people throughout the world. Particularly during the past ten years, the mobile radio communications industry has grown by orders of magnitude, fueled by digital and RF circuit fabrication improvements, new large-scale circuit integration, and other miniaturization technologies which make portable radio equipment smaller, cheaper, and more reliable. Digital switching techniques have facilitated the large scale deployment of affordable, easy-to-use radio communication networks. These trends will continue at an even greater pace during the next decade.1.1 Evolution of Mobile Radio CommunicationsA brief history of the evolution of mobile communications throughout the world is useful in order to appreciate the enormous impact that cellular radio and Personal Communication Services(PCS) will have on all of us over the next several decades. It is also useful for a newcomer to the cellular radio field to understand the tremendous impact that government regulatory agencies and service competitors wield in the evolution of new wireless systems, services, and technologies. While it is not the intent of this text to deal with the techno-political aspects of cellular radio and personal communications, second-politics are a fundamental driver in the evolution of new technology and services, since radio spectrum usage is controlled by governments, not by service technology development manufacturers, entrepreneurs, or researchers. Progressive involvement in technology development is vital for a government if it hopes to keep its own country competitive in the rapidly changing field of wireless personal communications.Wireless communications is enjoying its fastest growth period in history, due to enabling technologies which permit widespread deployment. Historically, growth in the mobile communications field has come slowly, and has been couple closely to technological improvements. The ability to provide wireless communications to an entire population was not even conceived until Bell Laboratories development of cellular concept in the 1960s and 1970s [Nob62], [Mac79], [You79]. With the development of highly reliable, miniature, solid-state radio frequency hardware in the 1970s,the wireless communications era was born. The recent exponential growthin cellular technologies of the 1970s, which are mature today. The future growth of consumer-based mobile and portable communication systems will be tied more closely to radio spectrum allocations and regulatory decisions which affect or support new or extended services, as well as to consumer needs and technology advances in the signal processing, access, and network areas.The following market penetration data show how wireless communications in the consumer sector has grown in popularity. Figure 1.1 illustrates of the 20th century. Figure 1.1 is a bit misleading since the curve labeled "mobile telephone" does not include nontelephone mobile radio applications, such as paging, amateur radio, dispatch, citizens band(CB), public service, cordless phone, or terrestrial microwave radio systems. In fact, in 1990, licensed noncellular radio systems in the U.S. had over 12 million users,more than twice the U.S. cellular users population at that time [FCC91]. With the phenomenal growth of wireless subscribers in the late 1990s, combined with Nextel's novel business approach of purchasing private mobile radio licenses for bundling as a nationwide commercial cellular service, today's subscriber base for cellular and Personal Communication Services(PCS) far outnumbers all noncellular licensed users. Figure 1.1 shows that the first 35 years of mobiletelephony saw little market penetration due to high cost and the technological challenges involved, but how, in the past decade, wireless communications has been accepted by consumers at rates comparable to television and the video cassette recorder.By 1934. 194 municipal police radio systems and 58 state police stations had adopted amplitude modulation(AM) mobile communication systems for public safety in the U.S. It was estimated that 5,000 radios were installed in mobiles in the mid 1930s, and vehicle ignition noise was a major problem for these early mobile uses [Nob62]. In 1935,Edwin Armstrong demonstrated frequency modulation(FM) for the first time, and since the late 1930s, FM has been the primary modulation technique used for mobile communication systems throughout the world. World War II accelerated the improvements of the world's manufacturing and miniaturization and televison systems following the war. The number of U.S. mobile users climbed from several thousand in 1940 to 86,000 by 1948, 695,000 by 1958, and about 1.4 million users in 1962[Nob62]. The vast majority of mobile users in the 1960s were not connected to the public switched telephone network. With the boom in CB radio and cordless appliances such as garage door openers and telephones, the number of users of mobile and portable radio in 1995 was about 100 million, or 37% of the U.S. population. Research in 1991 estimated between 25 and 40 million cordless telephone were in use in the U.S.[Rap91c], and this number is estimated to be over 100 million as of late 2001. The number of worldwide cellular telephone users grew from 25,000 in 1984 to about 25 million in 19993[Kuc91], [Goo91], [ITU94], and since then subscription-based wireless services have been experiencing customer growth rates well in excess of 50% per year. As shown in Chapter 2, the worldwide subscriber base of cellular and PCS subscribers is approximately 630 million as of late 2001, compared with approximately 1 billion wired telephone line. In the first few years of 21st century, it is clear there will be an equal number of wireless andconventional wireline wireless subscriber population had already abandoned wired telephone service for home use, and had begun to rely solely on their cellular service provider for telephone access. Consumers are expected to increasingly use wireless service as their sole telephone access method in the years to come.1.2 Mobile Radiotelephony in the U.S.In 1946, the first public mobile telephone service was introduced in twenty-five major American cities. Each system used a single, high-powered transmitter and large tower in order to cover distances of over 50 km in a particular market. The early FM push-to-talk telephone systems of the late 1940s used 120 kHz of RF bandwidth in a half-duplex mode(only one person on the telephone call could talk at a time), even though the actual telephone-grade speech occupies only 3 kHz of base-band spectrum. The large RF bandwidth was used because of the difficulty in mass-producing tight mobile telephone channels per market, but with no new spectrum allocation. I,proved technology enabled the channel bandwidth to be cut in half to 60 kHz. By the mid 1960s, the FM bandwidth of voice transmissions was cut to 30 kHz. Thus, there was only a factor of four increase in spectrum efficiency due to technology advances from WW II to the mid 1960s. Also in the 1950s and 1960s, automatic channel trunking was introduces and implemented under the label IMTS(Improved Mobile Telephone Service). With IMTS, telephone companies began offering full duplex, auto-dial, auto-trunking phone systems[Cal88]. However, IMTS quickly became saturated in major markets.By 1976, the Bell Mobile Phone service for the NEW York City market(a market of about 10,000,000 people at the time) had only twelve channels and could serve only 543 paying customers. There was a waiting list of over 3,700 people [Cal88], and service was poor due to call blocking and usage over the few channels. IMTS is still in use in the U.S., but is very spectrally inefficient when compared to today's U.S. cellular system.二、英文翻译：无线通信系统介绍自从马可尼在英吉利海峡首先证实了无线电波能保证持续不断的与海上航行的船只保持联系，移动通信便有了显著的发展。

5G无线通信网络中英文对照外文翻译文献

5G无线通信网络中英文对照外文翻译文献(文档含英文原文和中文翻译)翻译：5G无线通信网络的蜂窝结构和关键技术摘要第四代无线通信系统已经或者即将在许多国家部署。

然而，随着无线移动设备和服务的激增，仍然有一些挑战尤其是4G所不能容纳的，例如像频谱危机和高能量消耗。

无线系统设计师们面临着满足新型无线应用对高数据速率和机动性要求的持续性增长的需求，因此他们已经开始研究被期望于2020年后就能部署的第五代无线系统。

在这篇文章里面，我们提出一个有内门和外门情景之分的潜在的蜂窝结构，并且讨论了多种可行性关于5G无线通信系统的技术，比如大量的MIMO技术，节能通信，认知的广播网络和可见光通信。

面临潜在技术的未知挑战也被讨论了。

介绍信息通信技术（ICT）创新合理的使用对世界经济的提高变得越来越重要。

无线通信网络在全球ICT战略中也许是最挑剔的元素，并且支撑着很多其他的行业，它是世界上成长最快最有活力的行业之一。

欧洲移动天文台（EMO）报道2010年移动通信业总计税收1740亿欧元,从而超过了航空航天业和制药业。

无线技术的发展大大提高了人们在商业运作和社交功能方面通信和生活的能力无线移动通信的显著成就表现在技术创新的快速步伐。

从1991年二代移动通信系统(2G)的初次登场到2001年三代系统（3G）的首次起飞，无线移动网络已经实现了从一个纯粹的技术系统到一个能承载大量多媒体内容网络的转变。

4G无线系统被设计出来用来满足IMT-A技术使用IP面向所有服务的需求。

在4G系统中，先进的无线接口被用于正交频分复用技术（OFDM），多输入多输出系统（MIMO）和链路自适应技术。

4G无线网络可支持数据速率可达1Gb/s的低流度，比如流动局域无线访问，还有速率高达100M/s的高流速，例如像移动访问。

LTE系统和它的延伸系统LTE-A，作为实用的4G系统已经在全球于最近期或不久的将来部署。

然而，每年仍然有戏剧性增长数量的用户支持移动宽频带系统。

英文文献翻译(关于zigbee)

英文文献翻译1.1 StandarsWireless sensor standards have been developed with the key design requirement for low power consumption. The standard defines the functions and protocols necessary for sensor nodes to interface with a variety of networks.Someof these standardincludeIEEE802.15.4,ZigBee,WirelessHART,ISA100.11,IETF6LoW-PAN,IE EE802.15.3,Wibree.The follow-ing paragraphs describes these standards in more detail.IEEE802.15.4:IEEE802.15.4[37] is the proposed stan-dard for low rate wireless personal area networks (LR-WPAN's).IEEE802.15.4 focuses on low cost of deployment,low complexity, and low power consumption.IEEE802.15.4 is designed for wireless sensor applications that require short range communication to maximize battery life. The standard allows the formation of the star and peer-to-peer topology for communication between net-work devices.Devices in the star topology communicate with a central controller while in the peer-to-peer topol-ogy ad hoc and self-configuring networks can be formed.IEEE802.15.4devices are designed to support the physical and data-link layer protocols.The physical layer supports 868/915 MHz low bands and 2.4 GHz high bands. The MAC layer controls access to the radio channel using the CSMA-CA mechanism.The MAC layer is also responsible for validating frames, frame delivery, network interface, network synchronization, device association, and secure services.Wireless sensor applications using IEEE802.15.4 include residential, industrial, and environment monitor-ing, control and automation.ZigBee [38,39] defines the higher layer communication protocols built on the IEEE 802.15.4 standards for LR-PANs. ZigBee is a simple, low cost, and low power wireless com- munication technology used in embedded applications.ZigBee devices can form mesh networks connecting hun- dreds to thousands of devices together. ZigBee devices use very little power and can operate on a cell battery for many years. There are three types of ZigBee devices:Zig-Bee coordinator,ZigBee router, and ZigBee end device.Zig-Bee coordinator initiates network formation,stores information, and can bridge networks together. ZigBee routers link groups of devices together andprovide mul-ti-hop communication across devices. ZigBee end devic consists of the sensors, actuators, and controllers that col-lects data and communicates only with the router or the coordinator. The ZigBee standard was publicly available as of June 2005.WirelessHART:The WirelessHART[40,41] standard pro-vides a wireless network communication protocol for pro-cess measurement and control applications.The standard is based on IEEE802.15.4 for low power 2.4 GHz operation. WirelessHART is compatible with all existing devices, tools, and systems. WirelessHART is reliable, secure, and energy efficient. It supports mesh networking,channel hopping, and time-synchronized work com-munication is secure with encryption,verification,authen-tication,and key management.Power management options enable the wireless devices to be more energy effi-cient.WirelessHART is designed to support mesh, star, and combined network topologies. A WirelessHART network consists of wireless field devices,gateways, process auto- mation controller, host applications,and network man-ager.Wireless field devices are connected to process or plant equipment.Gateways enable the communication be-tween the wireless field devices and the host applications.The process automation controller serves as a single con-troller for continuous process.The network manager con-figures the network and schedule communication between devices. It also manages the routing and network traffic. The network manager can be integrated into the gateway, host application, or process automation control-ler. WirelessHART standards were released to the industry in September 2007 and will soon be available in commer- cial products.ISA100.11a: ISA100.11a [42] standard is designed for low data rate wireless monitoring and process automation applications. It defines the specifications for the OSI layer, security, and system management.The standard focuses on low energy consumption,scalability, infrastructure,robustness, and interoperability with other wireless de-vices. ISA100.11a networks use only 2.4 GHz radio and channel hopping to increase reliability and minimize inter-ference.It offers both meshing and star network topolo-gies. ISA100.11a also provides simple, ﬂexible, and scaleable security functionality. 6LoWPAN: IPv6-based Low power Wireless Personal Area Networks [43-45] enables IPv6 packets communica-tion over an IEEE802.15.4 based network.Low power device can communicate directly with IP devices using IP-based protocols. Using 6LoWPAN,low power devices have all the benefits of IPcommunication and management.6LoWPAN standard provides an adaptation layer, new packet format, and address management. Because IPv6 packet sizes are much larger than the frame size of IEEE 802.15.4, an adaptation layer is used. The adaptation layer carries out the functionality for header compression. With header compression, smaller packets are created to fit into an IEEE 802.15.4 frame size. Address management mecha- nism handles the forming of device addresses for commu-nication. 6LoWPAN is designed for applications with low data rate devices that requires Internet communication.IEEE802.15.3:IEEE802.15.3[46] is a physical and MAC layer standard for high data rateWPAN. It is designed to support real-time multi-media streaming of video and mu-sic.IEEE802.15.3 operates on a 2.4 GHz radio and has data rates starting from 11 Mbps to 55 Mbps.The standard uses time division multiple access (TDMA) to ensure quality of service. It supports both synchronous and asynchronous data transfer and addresses power consumption, data rate scalability, and frequency performance. The standard is used in devices such as wireless speakers, portable video electronics, and wireless connectivity for gaming, cordless phones, printers, and televisions.Wibree: Wibree [47] is a wireless communication tech-nology designed for low power consumption, short-range communication, and low cost devices. Wibree allows the communication between small battery-powered devices and Bluetooth devices.Small battery powered devices in-clude watches, wireless keyboard, and sports sensors which connect to host devices such as personal computer or cellular phones. Wibree operates on 2.4 GHz and has a data rate of 1 Mbps. The linking distance between the de-vices is 5-10 m.Wibree is designed to work with Blue-tooth. Bluetooth with Wibree makes the devices smaller and more energy-efficient. Bluetooth-Wibree utilizes the existing Bluetooth RF and enables ultra-low power con-sumption. Wibree was released publicly in October 2006.1.2 IntroductionWireless sensor networks (WSNs) have gained world-wide attention in recent years,particularly with the prolif-eration in Micro-Electro-Mechanical Systems (MEMStechnology which has facilitated the development of smart sensors.These sensors are small, with limited processing and computing resources, and they areinexpensive com-pared to traditional sensors. These sensor nodes can sense, measure, and gather information from the environment and, based on some local decision process, they can trans-mit the sensed data to the user.Smart sensor nodes are low power devices equipped with one or more sensors, a processor, memory, a power supply, a radio, and an actuator. 1 A variety of mechanical, thermal, biological, chemical, optical, and magnetic sensors may be attached to the sensor node to measure properties of he environment. Since the sensor nodes have limited memory and are typically deployed in difficult-to-access locations, a radio is implemented for wireless communica- tion to transfer the data to a base station (e.g., a laptop, a personal handheld device, or an access point to a fixed infra-structure). Battery is the main power source in a sensor node. Secondary power supply that harvests power from the environment such as solar panels may be added to the node depending on the appropriateness of the environment where the sensor will be deployed. Depending on the appli- cation and the type of sensors used, actuators may be incor- porated in the sensors.A WSN typically has ittle or no infrastructure. It con-sists of a number of sensor nodes (few tens to thousands) working together to monitor a region to obtain data about the environment. There are two types of WSNs: structured and unstructured. An unstructured WSN is one that con-tains a dense collection of sensor nodes. Sensor nodes 2 may be deployed in an ad hoc manner into the field. Once 2 In ad hoc deployment, sensor nodes may be randomly placed into the deployed, the network is left unattended to perform moni-toring and reporting functions. In an unstructured WSN, net-work maintenance such as managing connectivity and detecting failures is difficult since there are so many nodes. In a structured WSN, all or some of the sensor nodes are de-ployed in a pre-planned manner.3The advantage of a struc-tured network is that fewer nodes can be deployed with lower network maintenance and management cost.Fewer nodes can be deployed now since nodes are placed at spe-cific locations to provide coverage while ad hoc deployment can have uncovered regions.WSNs have great potential for many applications in sce-narios such as military target tracking and surveillance [2,3], natural disaster relief [4], biomedical health monitor- ing [5,6], and hazardous environment exploration and seis-mic sensing [7].Inmilitary target tracking and surveillance, a WSN can assist in intrusion detection and identification. Specific examples include spatially-corre-lated and coordinated troop and tank movements. With natural disasters, sensor nodes can sense and detect the environment to forecast disasters before they occur. In bio-medical applications, surgical implants of sensors can help monitor a patient's health.For seismic sensing, ad hoc deployment of sensors along the volcanic area can detect the development of earthquakes and eruptions.Unlike traditional networks,a WSN has its own design resource constraints.Resource constraints include a limited amount of energy,short communication range, low bandwidth, and limited processing and storage in each node. Design constraints are application dependent and are based on the monitored environment. The environment plays a key role in determining the size of the network, the deployment scheme, and the network topology. The size of the network varies with the monitored environ-ment. For indoor environments, fewer nodes are required to form a network in a limited space whereas outdoor envi-ronments may require more nodes to cover a larger area. An ad hoc deployment is preferred over pre-planned deployment when the environment is inaccessible by hu-mans or when he network is composed of hundreds to thousands of nodes. Obstructions in the environment can also limit communication between nodes, which in turn af-fects the network connectivity (or topology).Research in WSNs aims to meet the above constraints by introducing new design concepts,creating or improving existing protocols, building new applications, and develop-ingnewalgorithms.Inthisstudy,wepresentatop-downap-proach to survey different protocols and algorithms proposed in recent years. Our work differs from other sur-veys as follows:•While our survey is similar to [1], our focus has been to survey the more recent literature.•We address the issues in a WSN both at the individual sensor node level as well as a group level.•We survey the current provisioning, management and control issues in WSNs.These include issues such as localization, coverage, synchronization, network secu-rity, and data aggregation and compression.•We compare and contrast the various types of wireless sensor networks.•Finally, we provide a summary of the current sensor technologies.The remainder of this paper is organized as follows: Section 2 gives an overview of the key issues in a WSN. Section 3 compares the different types of sensor networks. Section 4 discusses several applications of WSNs.Section 5 presents issues in operating system support, supporting standards, storage, and physical testbed. Section 6 summa-rizes the control and management issues. Section 7 classi-fies and compares the proposed physical layer,data-link layer, network layer, and transport layer protocols. Section 8 concludes this paper. Appendix A compares the existing types of WSNs. Appendix B summarizes the sensor tech-nologies. Appendix C compares sensor applications with the protocol stack.1.3 Overview of key issuesCurrent state-of-the-art sensor technology provides a solution to design and develop many types of wireless sen-sor applications. A summary of existing sensor technolo-gies is provided in Appendix A. Available sensors in the market include generic (multi-purpose) nodes and gate- way (bridge) nodes. A generic (multi-purpose) sensor node's task is to take measurements from the monitored environment. It may be equipped with a variety of devices which can measure various physical attributes such as light, temperature, humidity, barometric pressure, veloc-ity, acceleration, acoustics, magnetic field, etc.Gateway (bridge) nodes gather data from generic sensors and relay them to the base station. Gateway nodes have higher pro-cessing capability,battery power, and transmission (radio) range. A combination of generic and gateway nodes is typ-ically deployed to form a WSN.To enable wireless sensor applications using sensor tech-nologies, the range of tasks can be broadly classified into three groups as shown in Fig. 1. The first group is the system. Eachsensor nodeis an individual system.In order to support different application software on a sensor system, develop-ment of new platforms, operating systems, and storage schemes are needed. The second group is communication protocols, which enable communication between the appli-cation and sensors. They also enable communication be-tween the sensor nodes. The last group is services which are developed to enhance the application and to improve system performance and network efficiency.From application requirements and network manage-ment perspectives, it isimportant th asensor nodes are capable of self-organizing themselves. That is, the sensor nodes can organize themselves into a network and subse-quently are able to control and manage themselves effi-ciently. As sensor nodes are limited in power, processing capacity, and storage, new communication protocols and management requirements.The communication protocol consists of five standard protocol layers for packet switching:application layer,transport layer, network layer, data-link layer, and physical layer. In this survey, we study how protocols at different layers address network dynamics and energy efficiency.Functions such as localization, coverage, storage, synchro- nization, security, and data aggregation and compression are explored as sensor network services.Implementation of protocols at different layers in the protocol stack can significantly affect energy consumption, end-to-end delay, and system efficiency. It is important to optimize communication and minimize energy usage. Tra-ditional networking protocols do not work well in a WSN since they are not designed to meet these requirements.Hence, new energy-efficient protocols have been proposed for all layers of the protocol stack. These protocols employ cross-layer optimization by supporting interactions across the protocol layers.Specifically, protocol state information at a particular layer is shared across all the layers to meet the specific requirements of the WSN.As sensor nodes operate on limited battery power, en-ergy usage is a very important concern in a WSN; and there has been significant research focus that revolves around harvesting and minimizing energy. When a sensor node is depleted of energy, it will die and disconnect from the network which can significantly impact the performance of the application. Sensor network lifetime depends on the number of active nodes and connectivity of the net- work, so energy must be used efficiently in order to maxi- mize the network lifetime.Energy harvesting involves nodes replenishing its en-ergy from an energy source. Potential energy sources in- clude solar cells [8,9], vibration [10], fuel cells, acoustic noise, and a mobile supplier [11]. In terms of harvesting energy from the environment [12], solar cell is the current mature technique that harvest energy from light. There is also work in using a mobile energy supplier such as a robot to replenish energy. The robots would be responsible in charging themselves with energy and then deliveringen- ergy to the nodes.Energy conservation in a WSN maximizes network life-time and is addressed through efficient reliable wireless communication, intelligent sensor placement to achieve adequate coverage, security and efficient storage manage-ment, and through data aggregation and data compression. The above approaches aim to satisfy both the energy con-straint and provide quality of service (QoS) 4 for the applica- tion. For reliable communication, services such as congestion control, active buffer monitoring, acknowledge-ments, and packet-loss recovery are necessary to guarantee reliable packet delivery. Communication strength is depen-dent on the placement of sensor nodes. Sparse sensor place-ment may result in long-range transmission and higher energy usage while dense sensor placement may result in short-range transmission and less energy consumption. Cov-erage is interrelated to sensor placement. The total number of sensors in the network and their placement determine the degree of network coverage. Depending on the application, a higher degree of coverage may be required to increase the accuracy of the sensed data. In this survey, we review new protocols and algorithms developed in these areas.1.1 标准协议：无线传感器标准已经发展出关键的设计要求低功率消耗。

无线通信文献翻译汇总

本科生毕业设计（论文）参考文献译文本译文出处：Xingming Wang.电流型CMOS图像传感器的电路模块设计. Chinese Academy of Sciences, 2000.4~32页院系光学与电子信息学院专业班级中法1202姓名胡越学号U201210300指导教师李微2015 年7月译文：电流型CMOS图像传感器的电路模块设计摘要本文介绍了电流型CMOS图像传感器的设计与实现，,该设计是基于CRVDC视频图像压缩(有条件的补充视频数据压缩)算法。

在CMOS芯片上进行预处理,可以实现压缩比为10:1且没有显著衰减的信号。

我们研究的主要内容为构建基本模块。

当图像传感器工作在电流模式时，正在建立的模块将会成为电流镜和电流比较器。

细致的分析了几种镜子后，我们选择共源共栅电流镜。

通过电路模拟和对原型设计的研究，我们证明了这个电流镜在200MHz 可以实现十一位的分辨率。

为了实现CRVDC算法，我们需要设计一个准确而且快速的电流比较器。

将两种新的电流比较器对比，并将对比结果和传统的电流比较器对比。

我们通过模拟和测量，证明了新的CMOS电流比较器在传播时延和功功率散耗上的性能比较好。

作为一个有源像素传感器的CMOS图像传感器，用于将入射光转换成光电流。

我们提出了可根据传感器的特征将其建模，并详细分析了它的性能，从而获得了将CMOS芯片压缩到标准的0.18μm的工艺技术。

自从我们知道了在一个正在运行的像素传感器的芯片上的电流特性可以生成大的固定的图像噪声（成像质量），电流型电路设计就采用了这种方法。

基于一个电流型芯片的成像质量的测试结果，我们得出了，该芯片的成像质量抑制比为0.35%。

同时，在一个芯片上，我们有必要将模拟信号转换为数字信号（ADC），以便用来实现数字型接口和有着8bitADC码的电流型管道的连接。

仿真结果表明，ADC码是单调的并且有一个完整的积分非线性±0.45的最低有效位和微分非线性±0.43的最低有效位。

短距离无线通信技术文献翻译

单位代码01学号1103020003分类号TN92密级文献翻译一个新的CMOS通道选择滤波器的双模式蓝牙/ WLAN直接变频接收机院（系）名称信息工程学院专业名称电子信息工程学生姓名xx指导教师xxxx2013年3月30日黄河科技学院毕业设计（文献翻译）第1页一个新的CMOS通道选择滤波器的双模式蓝牙/ WLAN直接变频接收机摘要：设计一个CMOS四阶通道选择滤波器集成双模蓝牙/ WLAN直接变频接收机芯片。

其带宽滤波器可以被编程从200 kHz到8 MHz容纳两个标准。

这种滤波器提供缓慢的权力，和小面积的设计解决方案。

布线模拟结果表明，该滤波器满足这两个应用程序的选择性和动态范围的要求，同时消耗1.88 mW的待机功率。

关键词：CMOS混合模拟/数字系统，电流型电路，主动滤波器，电流反馈放大1 简介在便携式设备和无线网络的应用程序中，使得无电缆环境发展的愿景更为可行。

它是短距离的无线传输系统，如蓝牙（BT）和无线局域网(WLAN)。

这种技术的主要目的是利用低成本、低功耗、体积小的单晶片处理语音和数据。

BT 和WLAN 的体系结构允许使用不同频率的无线接收器：高频、低中频和零频率(直接转换)。

但在双模式操作中，直接转换架构能够最大限度的利用各种构造块电流消耗。

因此, 在最小的外部组件中，它提供了一种低功耗、低成本的解决方案。

基带混频信号要求混频器的I / Q和单独的基带路径来持负频率的信息。

虽然这种体系结构遭受非线性直流偏移引起的自混频问题，但是为了避免饱和校正，可以用直流分量的方法解决直流偏移问题。

高动态范围的低通滤波器必须纳入在直接转换器的信道选择。

该滤波器的特性占每个接收机性能的主导地位。

这是因为，在天线接收到的信号经常包含比所需的频道频率较高的通道。

而滤波器必须能够处理大量信号的互调失真。

根据系统的规格，输入的射频信号的功率是BT-70dBm和无线局域网-76dBm。

然而，满足标准的误码率所需的信噪比在基带BT输出的是21dB,无线局域网输出的是10dB。

1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。

在CMOS芯片上进行预处理,可以实现压缩比为10:1且没有显著衰减的信号。

我们研究的主要内容为构建基本模块。

当图像传感器工作在电流模式时，正在建立的模块将会成为电流镜和电流比较器。

细致的分析了几种镜子后，我们选择共源共栅电流镜。

通过电路模拟和对原型设计的研究，我们证明了这个电流镜在200MHz 可以实现十一位的分辨率。

为了实现CRVDC算法，我们需要设计一个准确而且快速的电流比较器。

将两种新的电流比较器对比，并将对比结果和传统的电流比较器对比。

我们通过模拟和测量，证明了新的CMOS电流比较器在传播时延和功功率散耗上的性能比较好。

作为一个有源像素传感器的CMOS图像传感器，用于将入射光转换成光电流。

我们提出了可根据传感器的特征将其建模，并详细分析了它的性能，从而获得了将CMOS芯片压缩到标准的0.18μm的工艺技术。

自从我们知道了在一个正在运行的像素传感器的芯片上的电流特性可以生成大的固定的图像噪声（成像质量），电流型电路设计就采用了这种方法。

基于一个电流型芯片的成像质量的测试结果，我们得出了，该芯片的成像质量抑制比为0.35%。

同时，在一个芯片上，我们有必要将模拟信号转换为数字信号（ADC），以便用来实现数字型接口和有着8bitADC码的电流型管道的连接。

仿真结果表明，ADC码是单调的并且有一个完整的积分非线性±0.45的最低有效位和微分非线性±0.43的最低有效位。

我们的结果表明，我们的整个设计可以充分满足CMOS图像传感器的系统规范并且有可能倍用于前端处理模块在其他图像处理的应用程序上的动态检测和图像分割等动态环境中。

第一章介绍和论文大纲1.1介绍视频用于个人沟通的媒介、向导、导航、外层空间的探索、宇宙飞船…使网络带宽和视频压缩技术的可用性得到了越来越快的发展。

最初决定图像质量的为摄像机的图像传感器。

此外,图像传感器在集成电路驱动图像传感器和执行信号处理芯片上变得越来越重要。

我们关注的是应用在能量消耗的这一块，图像传感器自身的能量消耗是巨大的。

所以在大型图像格式处理图像处理任务时，这个问题变得尤为棘手。

我们希望获得理想的低制造成本、低功率、和有着良好的成像质量的图像传感器。

现在，两个应用的最多的图像传感技术为电荷耦合器(CCD)和CMOS图像传感器(互补金属氧化物半导体)(CISs)。

直到1990年代中期，CCD一直在图像领域中占领主导地位，而传统的ICs主要是基于CMOS技术制造出来的。

然而从那时起，CMOS图像传感器已经有了越来越多的发展。

这是因为，CMOS图像传感器的诸多的优点，如：低功耗、随机访问、集成度低、低成本，这些优点在很多生产应用中都是至关重要的。

因此，CMOS图像传感器在集成度低的优势上获得了很多潜在的应用，如：安全领域、生物识别技术和工业应用中。

1.2动机在图像传感系统中，信号的压缩变得尤为重要。

捕获的原始数据在预处理之前先发送到计算机，再通过通信渠道进行进一步的处理。

这将导致允许发送的数据减少且允许发送的数据会以更低的发送速率发送，从而减少了计算机的负载。

在给给定的通信通道传输视频信号时，我们需要确定传输所需要的带宽。

假设一个屏幕以每秒F帧的速度显示一个N×N的图像，则预期的传输频率应该是：=N⋅⋅N⋅N2/F)2/(2F对于每秒25帧的传输速率和625行/屏幕在正常的电视广播系统，视频信号的基本带宽约为5 MHz(这只提出了一个黑白图像)。

同样，对于图像传感器，需要有一个宽的带宽来读出来自各个图像传感器的图像数据。

而图像传感器的带宽是限制高像素成像的根本原因。

在1969年，F.W. Mounts提出了一个对电视信号进行编码的方法，这个方法利用了帧对帧的相关性来减少传输带宽。

这种方法被命名为CRVDC(条件补充视频数据压缩)算法。

他发现，当使用和录像、电话相似的信号以中等的幅度在屏幕中运动时，平均只有不到十分之一的两个连续帧之间的元素变化量是超过峰值信号的1%的。

所以，只有在那些连续的两帧信号之间存在着明显变化的数据才会被转移，而不是每一帧的每一个数据都会被转移。

这种有条件的补充算法可以达到10:1的压缩率且保证信号没有显著的衰减。

这样的发现在视觉通信系统中是十分有用的。

图1.1 一个条件补充发射机终端图1.1显示了发射机执行的操作。

在这个发射机中，摄像机的视频信号带宽有限,将其采样并数字化为8位的PCM(脉码调制)。

同时给我们提供了一个选择开关，但这个选择开关既不能在检测到两帧连续信号有显著差异时传输新信息，又不能另外传输内存中存储的信息帧。

框架内存中包含了延时线和有足够能力存储一个完整的帧的视频信息。

将相机中的数据与减法器电路中框架存储器中存储的参考数据相比较，同时新传入的信息和对应相同图片的参考数据，这两者的增益率有着较大的差异。

在每个样本空间内，由控制逻辑控制，而控制逻辑又依赖于绝对信号的幅度差异是否存在着显著的差异。

如果绝对信号的幅度存在着显著差异，那么控制逻辑的输出将会选择一个开关去选通一个新信号，并将其存储在帧存储器中。

如果绝对信号的幅度没有显著的差异，那么存储在帧存储器中的数据是可以流通的。

除了将新数据补充进入帧存储器中，控制逻辑还可以将新的信号数据和新信号数据的地址存储在缓冲区中。

存储在缓冲区中的数据是可以以恒定的速度读出的，按照先入先出的顺序读出。

为了平均补给率能和信道容量兼容，阈值的变化取决于存储在缓冲器中信息总量的函数。

随着阈值的变化变得很小，缓冲区存储的元素变少，允许变化不明显的数据去更新的阈值减小。

随着阈值的变化变大，缓冲器中存储的元素也将变多，阈值也将增大，同时该阈值也允许补充更显著变化的数据。

由于显著变化的数据的阈值的值在增加，改变较小的图像将会被丢弃，不能更改也不能复制，所以并不是所有的图片元素都对应同一个阈值。

这可能导致图片重叠在一起，如图1.2所示。

但这个问题会在几帧图像过后得到恢复。

一般来说，当压缩率为10:1时，恢复数据将会在短时间内完成。

在早些年，该算法是第一个提出数字压缩的。

1997年,k . Aizawa h . Ohno利用该算法在模拟域中实现了图像传感器阵列。

图1.2 第一个五帧，图像用100：15（最高）和100：5（最低）的压缩比改变。

（请注意图像在几帧后得到了重建）有条件的补充的新方案如图1.3所示。

将当前信号的像素与那些存储在内存中最后补充进来的帧相比较。

当绝对值的差大于阈值时，像素的值和地址将会被提取和编码。

虽然该算法比较简单，但是它仍然可以达到10:1的压缩率，信号也没有大的衰减。

如今，用信号处理是最受欢迎的图像传感器技术，与用信号处理相比,我们采用电流型信号处理技术来实现我们的设计。

电流型技术是利用电流来表示信号，在CMOS电路中电流信号的处理技术在最近几年也受到了极大的关注。

这是因为电流型信号处理技术相较于传统的用信号处理有很多的优势。

图1.3 模拟条件补充算法首先,由于非线性互补金属氧化物半导体晶体管的电流和电压之间的关系，一个在控制输入端电压的小的改变将会导致在输出端电流大的改变。

因此,对于一个固定的电源，电流型信号的动态范围应该比电压型信号的动态范围大。

即使电源电压较低，也总是有一个可以达到所需的动态范围。

因此，芯片的功耗将会降低。

这自然满足我们要求的低电源电压和低功耗芯片的设计。

其次，电流型电路比电压型电路要快得多。

在给定电路中，寄生电容将永远存在。

当电压改变时，这些电容必须充电或放电。

在电流型电路中，通过一个节点改变电流和通过一个节点改变电压比起来，通过一个节点改变电流并不重要，因此，寄生电容不会降低运转速度峰值。

第三,电流型电路与数字电路可以实现集成在同一使用了标准数字CMOS工艺的芯片。

这降低了芯片整体的成本。

最后,在许多应用程序中,探测器的输出信号和/或传感器(如CMOS图像传感器)本质上是电流。

使用电流型技术可以简化电路设计，还降低了布局的复杂性。

基于上述优点,我们可以得出结论，使用CMOS电流型技术，它确实是有利于设计用芯片处理的计算视频图像的。

1.3 研究目标视频图像压缩芯片的主要构件包括图像传感器、读出电路、电流镜、当前比较器、固定图形噪声(成像质量)抑制电路(用于CMOS有源像素传感器)和片上模拟-数字转换器(ADC)。

此外,辅助和控制电路,如当前基准电路、固定比率控制器电路、电压转换器电路和控制逻辑地址编码器/解码器电路是也必需的。

本文着重于设计和实现用电流型视频图像压缩芯片构建一个模块。

此外,我们不仅专注于该模块的分析也会优化该模块的性能。

本文的主要贡献如下:1.在系统级别上电流型CMOS图像压缩芯片的设计;2.对共源共栅电流镜和一种已经“证明”性能的改进了的电流镜的详细分析;3.设计、仿真和对一种使用了CRVDC算法的新的CMOS电流型图像传感器的性能分析;4.对一个CMOS线性有源像素传感器的描述和建模;5.设计和验证成像质量抑制电路的性能和相关的取样保持的电路;展示设计的模拟-数字转换器(ADC)。

1.4 论文大纲本论文的章节由一下部分组成：在第二章中,我们简要的描述了电流型图像压缩芯片。

然后，我们详细的描述了单个像素传感器的配置、CRVDC算法的实现和电路的定时控制。

怎样设计CMOS图像传感器，这个问题尤为突出。

最后，我们提出了图像传感器阵列系统的设计规范。

在第三章中，我们提出了替代电流镜的设计方案。

因为电流镜在我们的设计中是最常用的电路模块，他们的性能直接决定了整个成像系统的质量。

首先，我们描述一下基本电流镜的基本特征，然后是共源共栅电流镜，最后是受监管的共源共栅电流镜。

然后，我们将讨论怎样设计并改进受监管的共源共栅电流镜。

这将会有一些模拟测试和模拟测试的结果。

通过对比几个不同设计方案的模拟测量，我们得出，我们新提出的受监管的共源共栅电流镜的最佳性能可以满足我们的设计规范。

在第四章中，我们将分析，模拟和测量CMOS电流比较器。

首先，我们讨论了三种不同的CMOS电流比较器，这些电流比较器的设计在之前就已经被报道。

我们将它们的传播延迟和仿真结果与我们提出的两个新的CMOS电流比较器相比较。

然后，我们将详细的测量新电流比较器的性能并且将其性能与模拟比较器比较。