Constant Envelope Precoding and Non-Orthogonal Multiple Access for Massive MIMO Systems

Constant Envelope (CE) precoding is a transmission technique, which provides efficient power amplification and can be realised with a single radio frequency (RF) chain at the multi-antenna transmitter. In this paper, we study the multi-user massive MIMO broadcast channel with CE precoding and with non-orthogonal multiple access (NOMA). The motivation for this is to provide different multi-user interferance (MUI) energy levels to different users with different MUI requirements. Wepair users according to their channel conditions and examine the impact of the NOMA on MUI. Simulations for the independent and identically distributed Rayleigh fading channel show that different MUI energy levels is possible with NOMA under CE precoding.