Cooperative PSK constellation design and power allocation for massive MIMO uplink communications

Abstract

This paper considers a massive multiple-input multiple-output (MIMO) wireless uplink communication system over Rayleigh fading channels. In this system, two single-antenna nodes timely upload data to a base station (BS) with a large number of antennas on the same time-frequency resources. The small scale fading coefficients keep constant during two consecutive time slots, after which they change into new independent values. Assuming only the large-scale fading coefficients are available, we construct a maximum likelihood (ML) detector without the instantaneous small scale fading coefficients at the BS. The key idea is to utilize the absolutely additively uniquely decomposable constellation pair with a phase-shift keying (PSK) modulation scheme. Specifically, we use a rotated PSK constellation for one of the nodes to ensure the unique identification of transmitted symbols in a noise-free case. In a noisy case, we propose a power allocation framework for the proposed modulation scheme to improve the ML detector's average symbol error performance. Finally, simulations results verify the effectiveness of our proposed scheme.