Multiuser Cyclic Shift-Aided RA Code for Gaussian Multiple Access Channel

A multiuser cyclic shift-aided RA code is proposed for a Gaussian multiple access channel (MAC). In this scheme, every user utilizes a serial concatenated, which is constituted of regular RA code and spreading, followed by the identical chip-level interleaver and a user-specific cyclic shifter. The advantage is that our proposed code save bandwidth resources, and reduce storage space and high latency at the transmitters and receiver, since the identical interleaver serially concatenated the different cyclic shifters avoid complex interleaving operations and replace the random interleavers of IDMA scheme. A factor graph is utilized at the receiver for iterative multiuser decoding. Numerical results show that, our proposed multiuser cyclic shift-aided RA coding scheme supports to distinguish user and performs well in the error rate performance. Moreover, the performance of our proposed code exceeding that of the conventional IDMA scheme.