Group-based successive interference cancellation for multi-antenna NOMA system with error propagation

Non-orthogonal multiple access (NOMA) is viewed as a key technique to improve the spectrum efficiency and solve the issue of massive connectivity. However, for power domain NOMA, the required overall transmit power should be increased rapidly with the increasing number of users in order to ensure that the signal-to-interference-plus-noise ratio reaches a predefined threshold. In addition, since the successive interference cancellation (SIC) is adopted, the error propagation would become more serious as the order of SIC increases. Aiming at minimizing the total transmit power and satisfying each user's service requirement, this paper proposes a novel framework with group-based SIC for the deep integration between power domain NOMA and multi-antenna technology. Based on the proposed framework, a joint optimization of power control and equalizer design is investigated to minimize transmit power consumption for uplink multi-antenna NOMA system with error propagations. Based on the relationship between the equalizer and the transmit power coefficients, the original problem is transformed to a transmit power optimization problem, which is further addressed by a parallel iteration algorithm. It is shown by simulations that, in terms of the total power consumption, the proposed scheme outperforms the conventional OMA and the existing cluster-based NOMA schemes.