Combination of spatial modulation and non-orthogonal multiple access using hybrid detection scheme

Abstract

Among the key technologies that have been developed for efficient transmission for 5G, are spatial modulation (SM) and non-orthogonal multiple access (NOMA). In SM, multiple transmission antenna is modulated as information in order to increase capacity. On the other hand, NOMA allows to share the same frequency resources at the same time. Obviously, combination of these two techniques offers a new accomplishment for wireless transmission. In this paper, we develop a new technique to combine SM and NOMA for uplink transmission. A hybrid detection scheme is introduced in order to estimate information in receiver side. In transmitter, we set maximum transmission power for near-end user (NEU) and lower transmission power for far-end user (FEU). The main idea of our proposed detection scheme is to perform maximum receive ratio combining (MRRC) to obtain antenna index and then estimate the corresponding symbol for NEU. Afterwards, we apply successive interference cancellation (SIC) to the total received signal in order to eliminate NEU's signal. Finally, maximum likelihood estimation (MLE) is applied to the remaining signal to estimate FEU's antenna index and transmitted symbol. As the result, we also present the bit error rate (BER) comparison and achievable user and system transmission bits.