Fast Frequency Hopping System Synchronization Tracking Algorithm

The Frequency Hopping (FH) Communication, which is the most important type of spread spectrum communication systems, holds an excellent ability of anti-fading, anti-interfering and high security. Therefore,it has been widely used in military communications and civil mobile communication system. The Fast Frequency Hopping (FFH) Communication uses more than one frequency to transmit one symbol. At the presen, the rate of frequency hopping can reach more than 1000 hops per second. In the future, the rate will become more and more faste. Synchronization is the core of frequency hopping system. The quality of its design is not only related to the merits of system performance, but also directly affect the frequency hopping system can work properly. Based on these, we have studied the synchronization tracking algorithm in FFH communication system in this dissertation.Chapter one and chapter two introduce the meaning and the background knowledge of this dissertation. This dissertation briefly introduces FH communications, FFH communications, synchronization tracking of FH and synchronization of spread spectrum sequence. In this part, we also analyzed the two types of synchronization tracking loop, and introduced a variety of synchronization tracking loop algorithm of non-FFH system.Chapter three not only detailed studies the theory of the full-time early-late loop algorithm, traditional maximum likelihood (ML) algorithm, damp-surge loop and time-shared early-late loop, but also brings forward an ameliorative time-shared early-late loop algorithm, and analyses the performance of these five algorithms. The conclusion is: the ability of anti-fading of full-time early-late loop algorithm is not good, and the bit error rate (BER) of this algorithm is the largest. The wobble of damp-surge loop is the smallest, but its tracking speed is the slowest, and its stability is not very good. The wobble of ML algorithm is small, but its speed is slow. The wobble of time-shared early-late loop is the largest, but its speed is the fastest. The ameliorative time-shared early-late loop algorithm has the advantage of both above.Chapter four finishs the simulation of these algorithms which are introduced in chapter three in ideal channel, Gaussian noise, Rayleigh fading, partial band noise jamming,and multi-tone jamming channel. Simulation results consistent with the theoretical performance analysis.At last, chapter five summarizes the work of this dissertation and discusses the future of synchronization tracking in FFH communication system.