A Novel Partial Decode-and-Amplify NOMA-Inspired Relaying Protocol for Uplink Short-Packet Communications

Abstract

A novel partial decode-and-amplify non-orthogonal multiple access-inspired relaying (PDANR) protocol is proposed for uplink cooperative short-packet communication systems. Closed-form expressions for the average block-error-rate (BLER) of two cell-edge users are derived, based on which an asymptotic BLER expression is deduced to reveal valuable engineering insights into system design, including the transmit power and the number of antenna settings at a relay and a base station. Compared to conventional amplify-and-forward (AF) and decode-and-forward (DF) relaying protocols, the proposed PDANR protocol achieves superior BLER performance, particularly by saving considerable transmit power. Numerical results reveal two important observations: (i) there exists an optimal performance value when the distances between the relay and the users are approximately equal; and (ii) increasing users’ block length enhances the system’s overall BLER considerably.