Study Of The Anti-jamming Performance Of The Two-dimensional Spread Spectrum System

The spread spectrum communication has been developed very quickly because of its superior performance of anti-jamming while its appearance brought a significant break to the communication technologies. The original signal is spreaded in time and frequency domain simultaneously in the two Dimensional Spread Spectrum (2DSS) technology, which is the extension of traditional Direct Sequence Spread Spectrum (DSSS) and Multi-Carrier Code Division Multiple Access (MC-CDMA).In this thesis, the performance of anti-jamming in the 2DSS system will be mainly studied in a certain extent. After that, the principles and the algorithm of 2DSS over AWGN and Rayleigh channels with single-tone jamming will also be studied. Then the Bit Error Ratio(BER) performance of the single-tone jamming between the one dimension DSS system, MC-CDMA system and the 2DSS system under the AWGN channel will be discussed.First we introduce the characteristics and the development of the spread spectrum systems and the direction of study will be shown. The research state of 2DSS will be summarized in the second part in order to analyze the anti-jamming performance of the system more clearly.More and more people focus on the impact of wide-band and narrow-band interference to the spread spectrum communication. In this paper we will analyze the anti-jamming performance of the partial-band interference in 2DSS system comprehensively, and give the simulation results on anti-single-pulse jamming based on the platform of Matlab and Cossap.Then the impact of the normal single-tone jamming to 2DSS communication and the basic principle of anti-single-tone-jamming will be mainly analyzed. The BER of the anti-single-tone jamming over AWGN channel and multi-path Rayleigh channels in 2D-CDMA system will be derived, the simulation results of the BER will be provided as well. Then we conclude that the effect of the jamming can be almost eliminated, when the frequency of the jamming is exactly equal to the frequency of any sub-carrier, and a certain requirement of the 2D spreading-matrix is satisfied.At last, the performance of BPSK modulation between one and two dimensional spread spectrum system with single-tone jamming over AWGN channel will be compared and analyzed. The BER of the three systems will be analyzed, and the simulation results of the BER will be shown, then we conclude that the performance of the anti-jamming in 2D-CDMA system is between the DS-CDMA system and the MC-CDMA system under the same data bit rate and the same bandwidth.The technology of one dimensional CDMA can be considered as the special example of 2D-CDMA when the sequence of frequency domain set to all '1's. Thus the one dimension CDMA signals can be received by the technology of two dimensional receiver. The performance of the anti-jamming in one-dimensional DS system can be...