Channel Estimation and Receiver Design for URLLC in Distributed MIMO-NOMA Systems Uplink

Distributed multiple-input multiple-output non-orthogonal multiple access (D-MIMO-NOMA) is a potential technology for ultra-reliable low-latency communication (URLLC). In this paper, we propose a pilot scheme and derive a minimum mean squared error (MMSE) channel estimation algorithm in detail. Subsequently, a MMSE receiver for distributed MIMO-NOMA systems is designed by considering the channel estimation error and interference channel information, and the simulation results prove that the proposed receiver has better performance than the conventional MMSE receiver. Meanwhile, it is proved that there is an optimal pilot power allocation in any specific environment to minimize the mean squared error (MSE) of the proposed receiver.