A low complexity user scheduling algorithm aimed for the maximum number of active users in NOMA system

User scheduling algorithms in non-orthogonal multiple access (NOMA) have attracted much attention to improve the performance of the communication system. Here, a low complexity user scheduling algorithm aimed for the maximum number of active users in the single NOMA cluster ensuring the individual minimum rate requirement is proposed. Based on the precondition of the maximisation of the number of active users, the maximum sum-rate strategy is further integrated into the algorithm to compose a multi-round user scheduling algorithm. Moreover, a computational-complexity reduction algorithm is also introduced and has proved to be conveniently used in practical operation. Simulation results have shown that, compared with other existing user scheduling algorithms, the proposed user scheduling algorithms can achieve the maximum number of active users while ensuring their individual minimum rate requirements, and significantly improve the performance of the sum-rate among the cases when the maximum number of active users is achieved. Furthermore, the proposed multi-round and computational-complexity reduction user scheduling algorithms have shown better performance than the exhaustive search in terms of the computational complexity.

Automated summary

A user scheduling algorithm for NOMA systems is proposed in this study, which can achieve the maximum number of active users while meeting individual minimum rate requirements, and further improve performance through the maximum sum-rate strategy and computational complexity reduction algorithm.