Research And Implementation On Data Link Layer Technologies Of Hop-Spread Spectrum Communication System

The message transmission in the information age have to get rid of the old single wired transmission, and shows a wide range of wireless transmission technologies, like satellite communications, Bluetooth communications etc. But how to make the information transmission fast and reliable has never been stopped. For satellite communications, the performance of intercept probability, anti-jamming capability, anti-detection capability is particularly important. So, for the satellite communications, improving all aspects of performance mentioned above has become a primary goal.In the military communication situation, satellite communication is mostly common used. Anti-jamming capability of the communication technology is essential to the performance of military communication system evaluation criteria. The primary goal of the modern electronic warfare is to interfere the enemy’s communications system, so a communication system which has a strong anti-jamming capability will win in the electronic warfare. Anti-jamming communications technologies can be divided into three areas which are time domain anti-jamming technology, airspace anti-jamming technology, frequency domain anti-jamming technology; and the time domain anti-jamming technology mainly includes time-varying adaptive processing techniques; airspace anti-interference includes adaptive smart antenna; frequency domain anti-jamming technology is mainly about spread spectrum, frequency-hopping technology. Spread spectrum communication not only has a strong anti-jamming and anti-multipath performance, as well as the low probability of interception and easy operation for networking through the code division multiple access. So in the civil communication and military communication has been very widely used. On the basis of the direct spread spectrum communication, frequency hopping communication technology has better performance. Due to its technology matures, is gradually not only applied directly to the cellular network, satellite communication system, but also combined with the spread spectrum technology.With the emergence and development of software radio technology, the DS/FH hybrid communication technology implementation pointed out the direction for the satellite communications technology, and anti-jamming technology. Software radio technology, that is, in the communication process:using programmable signal processing technology from baseband to IF will be able to convert from the digital signal to the analog RF signal as late as possible and convert from the analog RF signal to the digital signal as early as possible in the information receive process. Thus, in the communication process, the signal generating, the communication mode and the signal processing can go digital, and can use software method, so that a device will be more compact, more powerful. All of these can help to create a big platform for the realization of the anti-jamming technology.The biggest bottleneck in the software radio technology is the processing speed of programmable digital signal processor. With the development of high-speed processing devices, software radio technology has been very rapidly developed. Studying the programmable DS/FH hybrid communication unit and the signal generating technology lays the foundation for a comprehensive anti-jamming technology.In this context, this paper introduced a communication system combined with direct spread spectrum mode and frequency hopping spread spectrum combination mode, mainly about its data link layer, including signal tracking, synchronization, channel encoding and decoding, as well as its concrete realization in FPGA research certain practical significance.