2003 Home Server for Home Digital Service Environments

Contributed PaperManuscript received July 14, 2003 0098 3063/00 $10.00 © 2003 IEEEHome Server for Home Digital Service EnvironmentsChangseok Bae, Jinho Yoo, Kyuchang Kang, Yoonsik Choe, and Jeunwoo LeeAbstract — This paper proposes a new scheme of the home server platform for providing home digital services by connecting home networks and the Internet. The proposed scheme is an integrated form of a home multimedia server, a home control server, and a home information server. The proposed system has an interface between access networks and home networks, various kinds of wired and wireless home networks devices, and multimedia processing modules. As examples of home digital services, the system provides a digital TV service, a remote multimedia service, and an instant message service based on the open service gateway initiative (OSGi) framework. We have implemented the proposed home server scheme, and verify that the system can be a core device of the home digital service environments 1. Index Terms — Home server, home networks, multimedia, OSGi, home digital service.I. I NTRODUCTIONIn home digital service environments, a home server can be considered as a core device for connecting and managing all of the information appliances within a home [1-3]. According to widespread use of high-speed networks such as the asymmetric digital subscriber line (ADSL), construction of access networks to connect the Internet from a home is entering into a complete stage. Recently, very high data rate digital subscriber line (VDSL) for supporting 20-50 Mbps begins to be serviced in Korea.Together with the construction of access networks, lots of standards for wired and wireless home networks are proposed and developed. Contrary to the access networks, a few kinds of home networks can already support very high data rates up to a few hundreds Mbps, and are going to support a number of Gbps in a few years. According to the rapid progress of home networks technologies, the fiber to the home (FTTH) plan for constructing fiber networks as access networks is promoted. These high-speed access networks and home networks are connected to each other and many kinds of Internet services can be available based on this environment.The first step of this effort starts with the appearance of digital information appliances like Internet refrigerators and1This work was supported in part by Korea Ministry of Information and Communication under Grant No. 02MC1510.C. Bae, J. Yoo, K. Kang, and J. W. Lee are with the Embedded Software Technology Center, Electronics and Telecommunications Research Institute, Daejeon, Korea (e-mail: {csbae, yoojh, k2kang, ljwoo}@ etri.re.kr).Y. Choe is with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea (e-mail: yschoe@yonsei.ac.kr). microwave ovens. Consequently, attempts to develop a homeserver for connecting and managing these appliances are continued naturally. However, these attempts are just in the beginning stage, and consensus for the configurations and functions of the system is under establishing now. Thus, the schemes and services of the home servers according to the advantage of companies proposing their own home server have different forms [1-6]. This paper considers three kinds of companies like communication companies, game companies, and consumer electronics companies.First, communication companies are mainly interested in networks functions of the home server. Erricson, one of the largest communication companies in Europe, developed a home server called E-Box [7]. The system employs open service gateway initiative (OSGi) [8] framework for providing home informatization and Internet services using home networks. It presents monitoring and controlling services for home automation devices, Internet sharing and firewall, and MP3 audio service through the Internet. Second, game companies are trying to develop a home entertainment server based on their game consoles. Sony considers PlayStation2, its world famous game console, as a next generation home entertainment server by adding network functions. Microsoft also developed X-Box as a network game server using its Ethernet port. Finally, consumer electronics companies, such as Matsushita, NEC, Hitachi, and LG also propose their own architecture of the home server adding PC functions to the consumer electronics products such as refrigerators.This paper proposes new architecture of the home server that can serve as a home multimedia server, a home control server, and a home information server, in a box. The proposed system integrates various kinds of home networks devices such as the Ethernet, the HomePNA, the IEEE1394, the power line communications (PLC), the WirelessLAN, and the Bluetooth. As a home multimedia server, the home server provides lots of multimedia services, for example watching a digital TV (D-TV) program and a DVD title. The home server, as a home control server, connects and controls all of information appliances within a home using its home networks devices. In addition, the home server can be a home information server by storing lots of home information in a storage device attached on it. The proposed system also equips an open service framework and many service bundles for easy management of various services available in the system. Therefore, users can enjoy lots of Internet services in their home by connecting the high-speed home networks and Internet using the home server. Furthermore, users can access, communicate, and control all ofinformation devices within their home through the Internet and home networks wherever they are.This paper consists as follows: Section 2 describes the concept of the digital home environments, and Section 3 explains architecture of the home server proposed in this paper. Section 4 presents implementation results of the proposed system, and finally, conclusions and future works are discussed in Section 5.II. D IGITAL H OME E NVIRONMENTSThe concept of home digital service environments with the home server is shown in Fig. 1. The home server connects all of information appliances within a home using home networks, and it interfaces home networks with access networks. Home networks devices are categorized into wired devices and wireless devices. Wired home networks devices include the Ethernet, the HomePNA, the IEEE1394, and the PLC. Generally, the Ethernet and the HomePNA are used to connect information devices such as computers, printers, and facsimiles. The IEEE1394 connects audio and video (AV) devices such as digital camcorders, digital VCRs, and digital audios. The PLC is used to connect white appliances like refrigerators, microwave ovens, and washing machines. Wireless home networks devices include the WirelessLAN and the Bluetooth, which can connect wireless devices like a personal display assistant (PDA) and a web pad.PLCIEEE 1394Bluetooth DTVDigital AudioGameWeb PADLightSecurityElectricity PDAWeb PADFig. 1. Concept of home server and home digital service environmentsThe home server, the core device of home digital services, is equipped with a large capacity of the storage device, and is responsible for control, management, and connection of all information appliances within a home. In addition, the system provides a method for communicating home information between family members.III. Architecture of Home ServerThe architecture of the home server is illustrated in Fig. 2, which can be divided into three groups: hardware devices, software modules, and contents and services. First, hardware devices in the home server consist of wired and wireless home networks devices for communicating among home information appliances, a digital TV receiver for watching HDTV programs, a multimedia codec for providing multimedia services, and a storage device for storing information and contents. Second, the software modules are categorized into system software and middleware. The system software includes a real time operating system (RTOS) for the home server, Java Virtual Machine (JVM), and open service gateway initiative (OSGi) framework. The middleware consists of the agent software, OSGi service bundles, and the control/multimedia middleware [9]. Finally, contents and services such as D-TV, remote medical, remote education, and cyber home services are available on this basis.H/WHomeServer H/W PlatformHome NetworksD-TV ReceiverMultimedia CodecS/WContents and ServicesStorage DeviceFig. 2. Architecture of the home server platformA. Hardware ModulesB. Home Networks Devices Wired Home Networks DevicesThe proposed home server has wired home networks devices such as the Ethernet, the IEEE1394, and the HomePNA. First, the Ethernet is the most basic wired homenetworks device. The system supports high-speed data communication using the chipset that can automatically detect either 10 or 100 Mbps Ethernet communication.Second, the IEEE1394 communication module consists of a physical IEEE1394 interface, a device driver forcommunication, and application program supporting play, record, and communication control functions of DV and MPEG-2 TS stream. The home server supports communication of DV data and MPEG-2 TS data between the devices connected to IEEE1394 devices. DV data communication usesDV1394 device driver that supports IEEE1394 isochronous transfer protocol and IEC61883 digital interface protocol. Instead of DV1394 device driver, MPEG1394 device driver is used to communicate MPEG-2 TS data. This module can reduce overheads for implementing multimedia data communication, because the device driver between IEEE1394 link layer and application program operates communication function transparently.Finally, the HomePNA uses a general phone line as a physical interface. The HomePNA can be easily configured because it has free topology and can use the existing network lines. Besides, the PLC for connecting white appliances such as refrigerators, microwave ovens and electrical washing machines is installed using power line serial lontalk adaptor (PL-SLTA).a) Wireless Home Networks DevicesThe proposed home server has dual PCMCIA slots for wireless home networks devices such as the WirelessLAN and the Bluetooth. The system has the WirelessLAN consisting of ad-hoc mode for playing the role of an access point. The Bluetooth also constructs an ad-hoc network in a home. The system employs the Casira bluetooth module and the OpenBT bluetooth protocol stack.b) Protocol StacksThe home server is the only device in a house that has a permanent IP address. It has the policy for assigning dynamic IP addresses for the information appliances within a home. The home server uses dynamic host configuration protocol (DHCP) for assigning IP addresses automatically to the home information devices. The home information devices confirm the existences of themselves using these dynamic IP addresses. The home server sets and performs firewall using a filtering style. The firewall to restrict the access of the data packets from unauthorized IP addresses is installed to guarantee the security of home networks. Users can set and modify the permission for access from specific addresses.Other information appliances except for the home server have dynamic IP addresses managed by the home server. All devices connected to the home networks communicate with outer devices using one representative IP address. The outer devices respond to the internal devices using the port number occupied by the internal device.2) D-TV ReceiverThe block diagram of a D-TV receiver module for the home server platform is shown in Fig. 3. The D-TV receiver module decodes the received D-TV broadcast signal using a tuner, an IF demodulator, an ADC, a VSB demodulator, and an MPEG decoder. HD size video data can be displayed on an HDTV through the video mux, which is employed to multiplex decoded video data and VGA (RGB) signal from the graphics module in the home server main board. Simultaneously, the D-TV receiver module can transmit VGA size video data to the multimedia codec module using the VIP port. Besides, the D-TV receiver can process additionally transmitted data broadcast as well as high definition video. In order to handle the electronic program guide (EPG), the D-TV receiver supports ATSC A/65 program and system information protocol (PSIP) standard [10, 11]. Therefore, users can utilize user-friendly information such as registered recording. Multimedia Codec ModuleThe multimedia codec module receives video data from a video in port. While video data is encoded to an H.263 [12, 13] stream, an error resilient scheme is implemented to reduceCodecTo HDTVFig. 3. Block diagram of D-TV receiver moduleThe multimedia codec module performs down sampling of input video using bilinear interpolation. VGA size input images are converted into CIF size images. In order to support remote multimedia service, the multimedia codec for a home sever should process at least 15 frames for CIF size video. The home server has to support various application services for multiple users as well as multimedia data processing. Thus, it is difficult to expect adequate quality of service (QoS), if the main processor of the home server is responsible for all of the multimedia codec functions.The proposed multimedia codec module shown in Fig. 4 makes use of a hardware module using a DSP and a field programmable gate array (FPGA) so as to reduce the load on the main processor and to support the required codec performance continually. While most parts of the codec algorithm are implemented in a DSP, motion estimation (ME) and motion compensation (MC) parts that require lots of computing time operate in a FPGA.Fig. 4. Block diagram of multimedia codec moduleC. S oftware ModulesThe proposed system employs Qplus [14], an embedded Linux developed by ETRI, as its realtime operating system. Qplus consists of reconfigurable embedded Linux kernel, system libraries, graphic window system, and target builder. The target builder is a tool for configuring Qplus, and this tool provides the functionality to configure all components of Qplus including kernel, system libraries, and applications. The system libraries are optimized to fit for embedded systems.Regardless of their location, users can check the states of the information appliances within a home under home digital service environments. In addition, whenever the predefined events occur in a home, it is necessary to notify the situation to the users using instant message service. Users generally require service provider to provide various service solutions operated in the home server. In the home digital service environments, many service providers located remotely support various services requested by users through the Internet. If all of the services make users purchase and install for themselves, it will be very inconvenient to apply the home server. For the users’ convenience, a dynamic service platform that can manage application services by remote service providers should be very useful. In the dynamic service platform, the remote service providers can install and remove services operated in a user’s home server by the user’s request. The OSGi service platform is a dynamic service platform, which satisfies this requirement. The platform consists of various service bundles and a framework that can easily install and operate service bundles at a remote site. Using OSGi, services are distributed as a bundle format, which will be installed, upgraded, operated, and removed without rebooting or restarting of the service platform. The system provides the OSGi service framework release 2.0 and its core bundles, and an instant message service as an example of service bundle. Fig. 5 shows the architecture of OSGi service platform. OSGi framework is implemented on the JVM, and core bundles, application bundles, and library bundles are implemented on this framework [15, 16].Core BundlesLibrary BundlesApplication BundleFig. 5. Architecture of open service platformIn addition, the system has control and multimedia middleware such as HAVi, Jini, and UpnP. Further, it also provides FiPA agent framework. D. C ontents and ServicesService applications using the home server include watching D-TV, remote medical services, remote education, and cyber home. Service provider can develop lots of services to implement digital home environment with the home server. At the remote side, service provider can enable or disable services in the user’s home using the OSGi framework.III. I MPLEMENTATION R ESULTSThe appearance of the proposed home server platform is shown in Fig. 6. The home server is developed using an x86-based processor, and integrates a few kinds of home network devices, an audio codec, and a graphics module on a board. The home server main board has an Ethernet port for uplink, 3 IEEE1394 ports, 4 USB ports, an AC97 audio codec, a VGA graphics module, and 3 PCI slots. A D-TV receiver, a multimedia codec, and a network add-on board are attached to PCI slots on the home server main board. The network add-on board has two PCMCIA slots for wireless home networks devices, an Ethernet port for downlink, and a phone line jack for the VoIP service.(a)(b)Fig. 6. Outside (a) and inside (b) of the home server platformAn example of D-TV broadcast reception is shown in Fig. 7. The D-TV receiver supports ATSC display formats such as 720p and 1080i. Besides, it can process program and system information protocol (PSIP) standard for electronic program guide (EPG). D-TV contents can be encoded into a low bit rate stream such as H.263 using a multimedia codec module.(a)(b)Fig. 7. D-TV receiving result. (a) Received D-TV picture and (b) EPG browsing resultAs an example of OSGi service bundle, an instant message service bundle is implemented. Because both SMS and VMS are considered as an instant message method, the service provider needs a CDMA module and a voice module to send a message to communication networks. If the predefined event is occurred in a home, the home server can send a message to the predefined user’s phone.Methods for the instant message service consider a voice message service (VMS) and a short message service (SMS) [16]. Fig. 8 shows the architecture of instant message service. The VMS requires a voice board for connecting PSTN, and the SMS requires a wireless modem for connecting CDMA. Considering the business model in OSGi structure, a service provider presents a service platform and service bundles in the home server, and manages the platform.Fig. 9 represents relations between required bundles and service platform in the home server. The instant message service requires a SMS service bundle, a VMS service bundle, and a transmission bundle for constructing message and for sending it to the service provider. In addition, device bundle is required to interface physical devices in a home.Service Provider Mobile & PSTN Fig. 8. Architecture of instant message serviceFig. 9. Configuration of home server sideSoftware and hardware components in the service provider are shown in Fig. 10. In order to provide instant message service, the service provider requires a software component for receiving and analyzing message packet transferred from a network device and for transferring the message as VMS or SMS format. Besides, physical devices such as a voice board and a wireless modem are required.PSTN networkFig. 10. Configuration of service provider sideThe home server communicates with the service provider using TCP/IP. The message format between the home server and service provider is shown in Table 1, which consists of 4 fields such as callee, caller, flag, and body. A colon is used as a delimiter to parse the message. The first field is a callee number, which represents a mobile or PSTN phone number ofthe receiver. The second field is a caller number. In order to be recognized in the service provider, both callee and caller numbers should be numeric numbers. If these fields have an error, the service provider notifies the home server. The third field is a flag, which represents the type of the message. If this field is 0 or 2, the default short message or voice message is sent to the receiver. The message in the body field is sent to the receiver by SMS, if it is 1. On the other hand, if it is 3, the file written in the body field is sent to the receiver. The last field is a body field, which is empty if the flag field is 0 or 2. If the flag is 1, it represents a short message. For the flag of 3, it represents a file name of a voice message.Table 1. Message format between home server and service providerFields Bytes Type RemarksCalleeVariableStringCallee number (variable length)Delimiter 1 Char Delimiter as a colonCaller Variable String Caller number (variable length)Delimiter 1 Char Delimiter as a colon Flag 1 Byte0: Default message for SMS(Body length = 0)1: Body message for SMS 2: Default file for voice (Body length = 0) 3: Body file for voice Delimiter 1 Char Delimiter as a colon Body Variable StringA message to be sent (variable length) IV. C ONCLUSIONS AND F UTURE W ORKS This paper describes a new scheme of the home server platform for implementing home digital service environments. Lots of related companies and corporations have consensus for the necessities of a home server. However, they still havedifferences in the definite realization method and form. The disagreement of opinion is caused by lack of consensus for the importance of services and by incompleteness of servicesprovided by connecting Internet and home networks using a home server. Communications, games, and consumer electronics companies are developing their own home server based on new concept devices improving their main product by adding partial functions needed in the home server. However, the home server in the digital home implemented by homenetworks should satisfy functions for home multimedia server, home control server, and home information server. This paper proposes and implements a home server formultimedia services, information appliance control services, and information management services. The home server has home network devices for connecting and controlling variousinformation appliances effectively. In order to process large size of multimedia data, the system has multimedia devices such as a D-TV receiver and a multimedia codec module. Open service framework and service bundles are implemented to provide a convenient service management method. The service provider at a remote site can easily manage services requested by users without users’ intervention.The home server is expected to be a core device for constructing information infrastructure that can create new services in a home. Therefore, it can activate markets for information appliances and application services. In addition, it can accelerate the development of new complex information appliances that can be used on an integrated environments of data, communication, broadcast, and home automation.R EFERENCES[1] C. Bae, J. Lee, and C. Kim, “State of the art and the developmentdirection of home server technology ,” Korea Information Processing Society Review, vol. 8, no. 1, pp. 28-41, Jan. 2001. [2] J. Lee and C. Bae, “ Home server platform technology,” Korea Information Science Society Review , Apr. 2001.[3] C. Bae, J. Yoo, K. Kang, Y. Choe, and J. Lee, “Home server for home digital service environments, Digest of Technical Papers in International Conference on Consumer Electronics , pp. 382-383, June2003.[4] A. D. Roy, “Networks for Homes,” IEEE Spectrum , pp. 26-33, Dec. 1999.[5] Nikkei Electronics, Japan moves ahead on futuristic home server , Oct.20, 1997. [6] C. Bae, J. Seok, Y. Choe, and J. Lee, “Multimedia data processing elements for digital TV and multimedia services in home server platform,” IEEE Trans. Consumer Electron., vol. 49, no. 1, pp. 64-70,Feb. 2003.[7] T. Idermark, M. Lilliestråle, and J. Vasell, “Erricson’s E-Box system-Anelectronic service enabler,” Erricson Review , no. 1, pp. 38-44, 1999.[8] OSGi, OSGi Service Platform Release 2, , Oct. 2001.[9] T. Y. Ku, D. H. Park, and K. D. Moon, “A Java-based home networkmiddleware architecture supporting IEEE1394 and TCP/IP,” IEEETrans. Consumer Electron., vol. 48, no. 3, pp. 496-504, Aug. 2002.[10] J.Whitaker, Digital television fundamentals , McGraw-Hill, 2000.[11] Digital television requirements for receivers , AS4933.1-2000, DraftVer. 3, 2000.[12] ITU-T, Video coding for low bit rate communication, ITU-TRecommendation H.263, Mar. 1996. [13] K. R. Rao and J. J. Hwang, Techniques and standards for image, video,and audio coding , pp.338-351, Prentice Hall, 1996.[14] C. Lim, G. Kim, and Y. Kim, “Reducing communication overhead in anembedded application development toolset,” Proc. of IASTD AI 2001, Feb. 2001.[15] K. Chen and Ligong, Programming open service gateways with Java embedded server technology , Addison Wesley, 2001.[16] K. Kang, D. Kang, and J. Lee, “SMS and VMS for an instant messagingin the future home environment,” Proc. of the ICOCM , pp.256-269,Gwangju, Korea, 2002.Changseok Bae received his B.S. and M.S. degrees in electronic engineering from Kyungpook NationalUniversity, Korea, in 1987 and 1989 respectively. He also received his Ph.D. degree in electrical andelectronic engineering from Yonsei University, Korea, in 2003. From 1989 to 1996, he was a seniorresearcher at Systems Engineering Research Institute, where he worked on image processing and patternrecognition. From 1997 to 1999, he worked with Korea Ministry of Information and Communication, where he participated inestablishing national software research and development policy. Since 2000,he has been a principal research staff of Embedded System Architecture Research Team at Electronics and Telecommunications Research Institute, where he is developing multimedia functions in the home server. His researchinterests include image processing, multimedia codec, home serverarchitecture, and information embedding.Jinho Yooreceived his B.S. and M.S. degrees in computer science from Kwangwoon University, Korea in 1994 and from Sogang University, Korea in 1996, respectively. From 1996 to 1998, he was a researcherat Research Institute of LG Information and Communications. Since 1999, he is a senior researcher at Electronics and Telecommunications Research Institute (ETRI). He has been and is developing system software that includes device drivers and components of operating systems in the home server box as a member of Embedded System Architecture Research Team. His research interests include operating system, hardware abstraction layer, hardware architecture, and compiler building in GNU. Kyuchang Kang received his B.S. and M.S. degrees in electronic engineering from Kyungpook National University, Korea, in 1994 and 1997 respectively. From 1997 to 2000, he worked on test and evaluation center at Agency for Defense Development as a researcher of engineering staff, where he developed Doppler signal analyzer and measurement system. Since 2001, he isworking on Computer and Software lab. at Electronics and Telecommunications Research Institute, where he is developing open service platform for the home server. He is also interested in mobile applications, distributed computing and network security.Yoonsik Choe received his B.S. degree in electrical engineering from Yonsei University, Korea, in 1979. He also received his M.S.E.E degree in systems engineering, M.S. and Ph.D. degrees all in electrical engineering from Case Western Reserve University, Cleveland, OH, the Pennsylvania State University,University Park, PA, and the Purdue University, Western Lafayette, IN, in 1984, 1987, and 1990, respectively. From 1990 to 1993, he was a principal engineer at Hyundai Electronics Industries, Co. Ltd., where he developed high definition TV. Since 1993, he has been with the Department of Electrical and Electronic Engineering at Yonsei University, Seoul, Korea, where he is an associate professor. Since 1988, he has been a member of Eta Kappa Nu. Since 2000, he has been the president of Signal Processing Research Center at Yonsei University. His research interests include video coding, videocommunications, statistical signal processing, and digital image processing systems. Jeunwoo Lee received his B.S., M.S., and Ph.D.degrees in electronic engineering from Kyungpook National University, Korea, in 1983, 1985, and 1998 respectively. Since 1985, he has been working at Electronics and Telecommunications Research Institute, and now, he is a principal research staff and the head of Embedded System Architecture Research Team where he is developing a home server platform. His research interests include information appliances, home serverarchitecture, and home digital services.。