抽象的

An Efficient Pattern Spreading in CHMA System

H.K.Ajai, L.Anish Gnanam

ABSTRACT:Code-hopping multiple access (CHMA) isatechnique in which the spreading code changes from one code to another. CHMAsystems are proposed for anti-interception. The perfect orthogonal complementary (POC) codeshelp to improve the performance of a CHMA system. POC characterize multiple access interference (MAI)-free and multipath interference (MI)-free operation.Data is transmitted by modulating it with the Perfect Orthogonal hopping codes. In the channel noise is added and with the same hopping code demodulation is achieved and original data is recovered. CHMA system isconvenient to build the big-area networks.The bit error rate(BER) is the key component consider for performance evaluation. The BER of a complementary-coded CHMA system with channel coding has less than traditional CHMA using Walsh codes.