A complementary codes based CDMA architecture for future wideband mobile communications

This article proposes a new CDMA architecture based on orthogonal complete complementary codes, characterized by its innovative spreading modulation scheme and its up and down-links signaling design. There are several advantages of the proposed CDMA architecture if compared with conventional CDMA systems pertinent to current 2G and 3G standards. Firstly, it can achieve a spreading efficiency (SE) close to one (the SE is defined as the amount of information bit(s) conveyed by each chip); whereas the SEs of the conventional CDMA systems equal 1/N, where N denotes the length of spreading codes. Secondly, it offers a multiple access interference (MAI) free operation in both up- and down-link transmissions in MAI-AWGN channels, which can significantly reduce co-channel interference responsible for capacity decline of a CDMA system. Thirdly, the proposed CDMA architecture in particular suits multi-rate transmission due to the use of an offset stacked spreading modulation technique, which simplifies rate-matching relevant to multimedia services and facilitates asymmetric traffic in up- and downlink transmissions for IP-based applications. This paper gives a evaluation study of the proposed CDMA architecture using computer simulation, based on which it is concluded that the proposed CDMA architecture has a great potential for applications in future wideband mobile communications beyond 3G.