Iterative Spatial Demapper with Repetition Codes for NOMA Network Coding

This paper proposes Iterative Spatial Demapping (ISM) for non-orthogonal multiple access (NOMA) network coding to support multi-user communication exploiting both channel coding and network coding. This paper uses repetition codes for channel coding and short Low Density Parity Check (LDPC) Codes as network coding. Two ISMs is used to represent the network box-plus operation connecting several users larger than available resources. We perform a series of computer simulations to evaluate the proposed NOMA network coding and evaluate some users having network degree distribution of one and two in terms of diversity order. We found that multiple ISMs work properly and help user detections although their signals are superposed due to less time resources compared to the number of users. We also analyze the performance using Extrinsic Information Transfer (EXIT) Chart to confirm the validity of ISM demapper. The results of this paper are expected to provide contribution to the development NOMA with the help of network coding.