Single Carrier Transmission in Massive MIMO Revisited

Abstract

Single-carrier (SC) modulation has been proposed as an effective waveform for massive multiple-input multiple-output (MIMO) systems. Previous studies have shown that the time-reversal maximum ratio combining (TR-MRC) is a simple yet powerful method to be used for SC massive MIMO systems under low signal-to-noise (SNR) conditions. However, in moderate to high SNR conditions, especially in realistic scenarios when the number of base station antennas is finite, multiuser interference leads to a significant amount of performance degradation. This interference is due to the residual cross-talk channels between different users after application of TR-MRC. To resolve this problem, in this paper, we propose a frequency domain multiuser detection technique in addition to TR-MRC. Our proposed technique is based on the minimum mean square error (MMSE) criterion. The additional computational complexity of our proposed technique depends only on the number of user terminals and does not grow with the number of base station antennas. This complexity can be further reduced through mathematical approximations in expense of a negligible performance loss as shown through our numerical results. We have investigated the performance of our proposed technique through simulations and computational complexity analysis where we have shown the superiority of our proposed technique to the existing ones in the literature.