通信工程外文翻译---一点多址扩频通信系统的应用

【附录】

英文文献

The Application of one point Multiple Access Spread Spectrum

Communication System

Liu Jiangang, Nanyang City, HenanProvince Electric Power Industry Bureau

【ABSTRACT】Spread Spectrum Digital Microwave communication as a communication, because their excellent performance have been widely used. The article in Nanyang City Power Industry Bureau one point Multiple Access Spread Spectrum Communication System as an example.briefed the spread spectrum communications, the basic concept and characteristics of the power system communication applications

.KEYWORDS：one point multiple access; Spread-spectrum communication; Attenuation

Nanyang City in the outskirts of Central cloth 35 to 11 kv substation farm terminals, their operation management rights belong to the Council East, Rural Power Company west (the eastern suburb of agricultural management companies -- four, the western suburbs of Rural Power Company Management 7), Scheduling of the various stations of the means of communication to the original M-150 radio and telephone posts. 2002 With the transformation of rural network, the remote station equipment into operation and communication channels to put a higher demand .As PUC Dispatch Communication Building to the east and west of farmers -- the difference between a company linked to fiber, Therefore, if 11 substations and the establishment of a transfer Link Building links Point may be the data and voice were sent to two rural power companies dispatch room, Rural Network scheduling for the implementation of automation to create the necessary conditions.

Given the status and power grid substation level, nature, taking into account the carrier and optical-fiber communications to conduct multiple forwarding, increasing the instability factor, considering the cost and conditions of the urban construction, Finally decided to adopt wireless spread-spectrum technology to establish that 11

farm terminal substation communication system. This paper describes the spread spectrum technology and the current system of the building.

1.The basic concept of spread-spectrum communication.

Spread Spectrum Communication's basic characteristics, is used to transmit information to the signal bandwidth (W) is far greater than the practical information required minimum (effective) bandwidth (△ F) , as the ratio of processing gain GP .

G P = W/△F

As we all know, the ordinary AM, FM, or pulse code modulation communications, GP values in the area more than 10 times, collectively, the "narrow-band communication", and spread-spectrum communications GP values as high as hundreds or even thousands of times, can be called "broadband communications."

Due to the spread-spectrum signal, it is very low power transmitters, transmission space mostly drowned in the noise, it is difficult to intercepted by the other receiver, only spreading codes with the same (or random PN code) receiver, Gain can be dealt with, and despreading resume the original signal.

2.The technology superiority of spread-spectrum communication .

Strong anti-interference, bit error rate is low.As noted above, the spread spectrum communication system due to the expansion of the transmitter signal spectrum, the receiver despreading reduction signal produced spreading gain, thereby greatly enhancing its interference tolerance .Under the spreading gain, or even negative in the signal-to-noise ratio conditions, can also signal from the noise drowned out Extraction, in the current business communications systems, spread spectrum communication is only able to work in a negative signal-to-noise ratio under the conditions of communication.

Anti-multi-path interference capability, increase the reliability of the system. Spread-spectrum systems as used in the PN has a good correlation, correlation is very weak. different paths to the transmission signal can easily be separated and may in time and re-alignment phase, formation of several superimposed signal power, thereby improving the system's performance to receive increased reliability of the system.

Easy to use the same frequency, improving the wireless spectrum utilization.Wireless spectrum is very valuable, although long-wave microwave have to be exploited, and still can not meet the needs of the community. To this end, countries around the world are designed spectrum management, users can only use the frequency applications, rely on the channel to prevent the division between the channel interference.

Due to the use of spread-spectrum communication related receive this high-tech, low signal output power ( "a W, as a general-100 mW), and will work in the channel noise and thermal noise in the background, easy to duplicate in the same area using