Performance of Adaptive Modulation Scheme for Adaptive Minimum Symbol Error Rate Beamforming Receiver

Abstract

This paper considers adaptive beamforming receiver that support multiple users, each having one transmit antenna. In certain circumstances, symbol error rate (SER) performance of the beamforming receiver degrades severely. In order to minimize the SER, minimum symbol error rate (MSER) beamforming receiver is utilized. Then, we propose an adaptive modulation scheme for the receiver to maintain the average SER below the target SER while maximizing the average throughput. The scheme uses the information on the direction of arrival and the average signal-to-noise ratio to decide the appropriate modulation mode. For comparison, the proposed scheme is also applied to minimum mean square error (MMSE) beamforming receiver system. Simulations were carried out in the presence of single and two interferers. Simulation results show that the performance of the proposed algorithm employing MSER beamforming is superior to its MMSE counterpart, with the largest advantage of 0.21 in the outage probability.