MMSE-Based MIMO Receiver for Cooperative Downlink NOMA in LEO Satellite Networks

We propose a novel minimum mean square error (MMSE)-based receiver with multiple antennas for downlink cooperative non-orthogonal multiple access (NOMA) systems in low earth orbit (LEO) satellite networks. In this paper, we focus on a common user equipment (UE) that exists in a cell cross-region serviced by two adjacent satellites. With the proposed technique, the common UE utilizes the advantage of multiple receiving antennas when receiving the NOMA signal containing its own signal through orthogonal frequencies from both two satellites. Through computer simulations, we show that the proposed MMSE-based NOMA receiver outperforms the conventional selection combining-based receiver in terms of bit-error rate performance.