System Design and Performance Analysis of M-ary Complementary Coded Multiple Access

Future wireless communications need to support massive connectivity with an increasing number of connected devices. In this work, an M -ary complementary coded multiple access ( M -ary CCMA) scheme is proposed for its applications in future wireless communications with a large overload ratio. Data streams from different users in an M -ary CCMA system are mapped to different combinations of codewords generated by a complementary code set. The combinations of codewords share the same time-frequency resources. Compared to traditional orthogonal frequency division multiple access (OFDMA), the proposed M -ary CCMA can support a larger overload ratio and a higher spectral efficiency. On the other hand, M -ary CCMA ensures a lower bit error rate (BER) performance at the same overload ratio than a traditional non-orthogonal multiple access (NOMA) scheme, making it a very attractive multiple access scheme for future wireless communications.