Performance Analysis Of Differential Frequency Hopping Systems

The poor channel condition is the bottleneck for the High Frequency(HF) communications to support the high rate transmission for many years. The differential frequency-hopping (DFH) system is a novel approach for reliable high rate HF data transmission. Rencently, DFH has received increasing attention in academe areas. However, the most of the researchs are focused on the frequencies transition function(FTF). A few researchs have been done on performance analyses for DFH system over additive white Gaussian noise (AWGN) channels and Rayleigh fading channels. But the anti-jamming performances of DFH system have not been studied by now. The anti-jamming performance is very important for military communications. It is worth to study the anti-jamming performances over HF channel, which is modeled as Rayleigh fadding channel for simplification. There is distinct difference between DFH and conventional Frequency-hopping (FH), so the suitable techniques of signal detection are also worth to be investigated. The performances of anti-jamming and anti-fading are studied in detail. The multi-user environments are considered in this work. Several signal detection methods, which can be used in DFH system, are proposed in this thesis. This thesis is organized as following.The basic model of DFH system is desribled in the thesis.Accroding to the characteristic of DFH techniques, an effective FTF is provided. Five types of signal receivers is proposed according to the methods of the signal detection in DFH system. The performances of DFH system over AWGN channels are analyzed and verified with simulations.The performances of DFH system with partial band jamming (PBJ) and multi-tone jamming (MTJ) are studied respectively. In the performance analyses ,two types of receivers are considered ,including symbol-by-symbol (SBS) detection and sequence detection with linear-combining (SDLC). A novel FH technique, adaptive differential frequency hopping (ADFH), is proposed. ADFH can achieve some new advantage with the combination of DFH and adaptive frequentcy hopping (AFH). The performances of ADFH system with PBJ are studied in theory, and the differences between ADFH and...