Reed-solomon Code In The Wireless Q-signal Design

The communication by wireless challenge-response signals is the main approach to cooperative target recognition and the reliability of signal transmission is the guarantee of the IFF system's performance. This paper offers a method of designing the set of reliable signals, which combines the applications of Reed-Solomon codes and mixed spectrum spread techniques.In the first two chapters, the main active CTR systems and the theory of wireless challenge-response signal design are investigated. The definitions of PPK signal and PPK signal train are given, as well as that of signal set. RS coded pulse position keying signal train is considered as the basic signal structure where this design starts from.Chapter 3 begins from the analysis of RS codes'correlation and then gives the method of RS signal set design exploiting multi-polynomials, which is different from traditional way of using only one polynomial. As a result, RS signal set A based on 6 polynomials and RS signal set B based on 3 polynomials are presented. As the decoding part, we discuss the relationship between BM algorithm and LFSR synthesis and some explanations as well as supplementary provements for LFSR synthesis iterative algorithm are given. Errors-and-erasures correcting algorithm for RS code is also brought forward to improve the coding gain.Chapter 4 focuses on the algorithms of PPK signal detection and hard decision in AWGN channel. There are two approaches to the detection of PPK signals, namely extremum detection and threshold detection, whose performances for PPK signal trains composed of 31 pulses are calculated and plotted in this chapter. Considering the demand for real time, FFT is made use of to quicken correlation operation. For PPK signals of 16 time slots, FFT correlation is carried out by computer to prove the performance of extremum detection. Non-coherence detection for intermediate frequency signal of DS-PPK is also taken into account and a non-coherence detection algorithm is offered to solve the problems brought by unknown phases. A processing structure is presented at the end of this chapter.In chapter 5, the coding gain brought by RS codes is calculated. For t=10 and 14, RS codes brings about 5dB and 7dB respectively. Applications of RS codes in identification and in frequency hopping address coding are also discussed. Chapter 6 summarized the whole paper and gives the expectations for following work.