Low-complexity beam selection and user scheduling algorithm for millimeter-wave communication

Aiming at the problem of high complexity of user scheduling scheme in millimeter-wave hybrid beamforming(HBF)system, two low-complexity beam selection and user scheduling joint optimization algorithms are proposed. The hybrid architecture makes user scheduling face new challenges and becomes a joint optimization of analog beam selection and user scheduling. This paper considers the practical scenario that the transmitter can not obtain perfect channel state information(CSI), the beam training based on fixed codebook is used to obtain equivalent CSI, scheduling indicator function is introduced and the joint optimization problem is modeled into non-convex combination program. Therefore, we propose two sub-optimal solutions with low complexity, which are based on particle swarm optimization(PSO)and greedy algorithm. The simulation results show that proposed algorithms can make a good compromise between performance and complexity, compared with the exhaustive searching(ES).