Research On MC-CDMA Communication System Based On Chaos Theory

MC-CDMA is an important basic technology of future mobile communication systems,With the increase of the number of mobile communication system subscriber,the demand for spreading codes number is growing.The chaotic map system can generate a large number of code sequences with good correlation,can well overcome the limitations of traditional pseudo-random codes quantity and are used in MC-CDMA communication system,and also provide a new research direction for communication system performance,improving performance of communication system.First of all,this paper analyzes the chaos theory and system,then the spread spectrum code sequence based on chaotic system and its performance are studied in this paper.Finally a new approcach to generate chaotic sequence with multiple iterative initial value and adaptive random selecting chaos-fractal parameters is proposed by simulating and analyzing chaotic sequences generated by four classic discrete chaotic map(Logistic map and improved Logistic map,Tent map and Chebyshev map).The simulation results show that the new chaotic sequences have better performance in initial sensitivity,balance and correlation compared with m sequences and Gold sequences.Monte Carlo simulations based on MTALAB of an MC-CDMA system with the new chaotic sequence for multi-user show that new chaotic sequence are better than those of m sequences and gold sequences in properties of user capacity,anti-multipath,anti-mai and BER.With the signal-to-noise ratio increases,the new chaotic sequence has better error rate performance than m sequence and Gold sequence,can achieve better communication performance in MC-CDMA communication system.