A Unified Multiuser Coding Framework for Multiple-Access Technologies

In this paper, multiple-access techniques are viewed as generalized coding schemes to support both multiuser separation and coding gain. In this sense, the traditional coding schemes, e.g., low-density parity-check (LDPC) code, can be viewed as a special case. Note that still a big difference exists between multiple-access techniques and LDPC codes. In particular, both binary and nonbinary LDPC codes are generated based on finite field theory, whereas multiple-access works based on not necessarily a finite field. This paper presents a mathematical framework, called 'multiuser coding,' to unify multiple-access and traditional coding theories. To verify the proposed framework, we propose a uniquely decodable mapping based codebook for futuristic multiple-access communications. A three-dimensional Tanner graph based message passing algorithm is introduced for multiuser detection. Simulation results show that the proposed scheme can support a large number of users with a promising performance.