Performance Analysis of Short-Packet NOMA Systems Assisted by IRS With Failed Elements

This paper analyzes the performance of a short-packet non-orthogonal multiple access (NOMA) communication system assisted by an intelligent reflecting surface (IRS) whose reflecting elements suffer a certain failure probability. Both optimal phase shifts and one-bit phase errors are considered for the IRS. Closed-form asymptotic expressions for the average block error rate (BLER) at the NOMA users are obtained for both cases, which facilitate the investigation to the performance loss caused by phase errors and failure reflecting elements of the IRS. Numerical and simulation results have validated the accuracy of the developed theoretical analysis, and show that phase errors and partial failure reflecting elements of the IRS degrade the BLER performance of short-packet communications. They also show that IRS-aided short-packet NOMA systems outperform those in orthogonal multiple access in the whole signal-to-noise ratio range.