Multi-sub-channels Spread Spectrum Anti-interference System and its Performance

Abstract

Abstract-Based on direct sequence spread spectrum, M-ary spread spectrum, multicarrier code division multiple access (CDMA), orthogonal frequency division multiplexing (OFDM) technology, etc., a new wireless communication anti-interference system, i.e. multi-sub-channels spread spectrum (MSCSS) system, has been proposed here. Transmitting end of the system processes spread spectrum twice using channel pseudo-random code and sub-channel pseudo-random code. Each bit of digital baseband signal was transmitted, through time-division manner, with 16 spread spectrum sub-channel signals. Pseudorandom codes of each spreading sub-channel are orthogonal to each other, so is the center frequency. Meanwhile, receiving end processes every bit of information in manner of parallel accumulation and adaptive threshold decision, to achieve receiving and processing of relevant multi-sub-channel spread spectrum signals, thereby improving noise immunity of communication system. Theoretical analysis and simulation results show that anti-interference capacity of the system is superior to traditional hybrid spread spectrum communication system. In detail, at the same information rate and the same bandwidth, its interference tolerance is higher than that of the hybrid DS/FH spread spectrum system by 5 dB.