Exact Packet Outage Expressions of Multi-user Detection with Adaptive Successive Interference Cancellation for Wireless Systems in Slow Fading Channels

In this paper, an exact expression has been derived for the outage probability and the total system goodput of multi-user detection (MUD) based on successive interference cancellation (SIC) for multi-user communication system. We consider a single antenna wireless system with n mobile users and a base station. We focus on the uplink direction with perfect channel knowledge (CSIR) at the base station. We consider slow fading channels where packet outage is the primary concern even if capacity achieving coding is applied. To capture the effect of packet outage, we consider the packet outage probability and the total system goodput of the n users. The analytical expressions for packet outage probability and system goodput are very important for cross layer optimizations of multi-user systems with MUD. However, due to the SIC processing in the MUD, the outage probability analysis is not trivial as the outage probability of the n users are coupled together. In this paper, we shall propose an analytical approach to evaluate the exact expressions of the packet outage probabilities and the system goodputs for the n users based on ordered statistics. We consider adaptive SIC where an optimal decoding order for the MUD is found per fading slot. Simulation results and discussions are given to verify the analytical expressions. From the results, the system goodput increases with the average user SNR and the number of the users with diminishing returns at large SNR and number of users.