Adapting SCMA Codebooks to Channel State

Non-orthogonal multiple access (NOMA) methods are a promising technology for organizing the physical layer of next generation communication networks. Sparse code multiple access (SCMA) is one of the most efficient NOMA implementations. The SCMA method is based on the use of codebooks - sets of sparse signals. The structure and content of codebooks determines the communication rate and interference immunity. This paper describes the transmission of communication system signals to SCMA in multipath communication channels with a frequency selective fading. The method of codebooks adapting for transmission channel state has been proposed. The bit error rate (BER) performance of this method has been estimated for various channel models corresponding to 5G FR1 systems and for various channel estimation accuracy. The effectiveness of the proposed method has been shown. The research results can be applied in other NOMA systems.