Average BLERs Analysis of Downlink NOMA Short-Packet Communication Systems

This paper examines a two-user downlink non-orthogonal multiple access (NOMA) short-packet communication system in flat Rayleigh fading channels. To accurately assess the average block error rate (BLER) of the system, novel methodologies utilizing two-dimensional inverse Laplace transform are introduced, in contrast to existing works that either neglect or provide a lower bound for the product term. Additionally, a rigorous theoretical derivation of the approximation expression for the product term in the downlink NOMA system is presented. The efficacy of the derived expressions is validated through comprehensive numerical results.