Complementary spreading CDMA systems under electrical and multipath interferences

The BER performance of presented CDMA systems will rapidly deteriorate under the conditions of strong electrical and multipath interferences. To solve the problem, this paper develops a complementary spreading CDMA (CS-CDMA) system with complementary codes. Different from the classical CDMA systems, the base station of CS-CDMA assigns complementary spreading codes for every mobile stations, the mobile station despreads the data flow by two complementary matching filters. The mobile receiver will curb the effects of strong electrical interference and multipaths interference by their complementary characteristics of cross-correlation, so the system performances (BER and SINR) can be improved much. Since presented complementary spreading codes cannot exhibit good BER performance for the strong interference, this paper develop a new kind quasi-complementary spreading codes. The paper analyzes the performance of complementary spreading CDMA systems theoretically and experimentally for under such electrical and multipath conditions. The simulation results show the good BER performance of the proposed CS-CDMA scheme.