Based On Coherent Detection Of The Iterative Interference Rejection Techniques

Though the technology of wireless communication is developing rapidly, there are kinds of jamming in the real wireless communication systems. The whole communication system can not work effectively with nothing done to the existed interference. Therefore, how to suppress the interferences effectively is one of the important objectives of communication system.Since the turbo code achieved good performance by using the technique of iterative decoding, its idea is also applied to other fields, such as iterative equalization, iterative demodulation and decoding and so on. The technique of iterative interference suppression based on coherent detection in wireless communication systems is mainly studied in this paper.The background and its significance of this topic are described at the very beginning. Then the technique of iterative interference suppression and iterative detection is analyzed, and the contents of this dissertation are introduced briefly.The performance of iterative suppressing the partial-band jamming and multi-tone jamming in frequency-hopping system based on continuous phase modulation is researched in chapter two. First of all, the system model of FH-CPM is introduced and the signal features of CPM are analyzed. It is a kind of modulation with memory. The Serially concatenated system can be composed of CPM and channel coding. Then the soft-input soft-output algorithm of M-ary CPM is described in detail. The principle of iterative estimating the jamming state information is introduced. Finally, the performances of iterative suppression the partial-band jamming of M-ary FH-CPM are analyzed. The technique of iteratively suppressing the multi-tone jamming is also investigated in this chapter. Then the performance of iteratively suppressing multi-tone jamming is analyzed.The performance of iterative suppressing the partial-band jamming and multi-tone jamming in space-time frequency-hopping CPM system is mainly studied in Chapter three. CPM is a kind of modulation with memory. The traditional demodulation technique is based on the trellis, whose complexity is relatively too high. If this kind of demodulation is used in CPM system, the high complexity of the receiver would be unacceptable. Therefore, the low-complexity technique of iterative suppressing interference is investigated in this chapter. The memory of CPM signal is eliminated by introducing Laurent decomposition and differential precoding. Then a linear detection algorithm based on soft-input soft-output is proposed. The complexity of the receiver is reduced significantly. Combing with channel decoding and estimating the jamming, the iterative detection, estimating and suppressing the interference can be realized. In the end, the performance of iteratively suppressing partial-band jamming and multi-tone jamming in space-time FH-CPM system is analyzed.The technique of iterative interference suppression in OFDM system is mainly investigated in Chapter four, including the partial-band jamming and single tone jamming. In the fading channel, the traditional receiver with time domain and frequency domain equalization is not applied in the proposed system. The method of BICM is applied. The receiver achieves iterative gains through exchanging extrinsic information between demodulator and decoder. In this chapter, an algorithm of iterative estimating jamming state information is proposed specially for OFDM systems based on linear modulation so as to gradually improve the correct rate of estimating JSI with the iterative estimation and then improve the performance of the whole system. The technique of suppressing single tone jamming in fading channel is also investigated in this chapter. The receiver reconstructs the single tone jamming by estimating the amplitude and phase and then eliminates the jamming from the receiving signal.In chapter five, a low-complexity technique of iterative suppressing partial-band jamming and single tone jamming is studied. The system can detect iteratively without coding and decoding by introducing the energy-spreading transform. In this chapter, the technique of suppressing partial-band jamming and single tone jamming iteratively based on time domain and frequency domain is studied and the performance of anti-jamming of the proposed system is analyzed.In the end, the contents of this dissertation are summarized. Some advices for the next steps are proposed. Then the development of the technique of iterative interference suppression is introduced in brief.