A new radio access scheme based on CDMA for B3G wireless communications

A new scenario of multiple access technology for beyond 3G wireless communications named CDD- dual-CDMA is proposed. CDD (code-division duplex) is a method to improve the spectrum efficiency by adding smart codes into time-division duplex (TDD) technology. The concept of dual-CDMA (dual-code division multiple access) is dividing traffic channels by both LAS (large area synchronous) codes and LS (loosely synchronous) cods, in order to eliminate inter-symbol interference (ISI) and multiple access interference (MAI). At the same time, the problem that the number of available smart codes is limited could also be solved. In the paper, the performance of CDD- dual-CDMA is analyzed. The result of simulation shows that BER (bit error rate) performance of CDD- dual-CDMA is much better than traditional random codes. Additionally, CDD- dual-CDMA scenario is a flexible scheme, and can be used for improvement of TD-SCDMA system. Therefore, CDD- dual-CDMA scenario is more suitable for the future mobile communications.