Performance evaluation of ARQ systems

Abstract

This final year project is entitled with 'Performance Evaluation of ARQ Systems'. By taking multiple access systems as an example, this paper is mainly focused on the performance of ALOHA-type random access systems. By introducing multi-user detection (MUD) at the receiver, we can study the capability of multiple packets reception (MPR) dealing with packets with different power levels which follow a certain distribution f. After calculation and optimization, we are able to work out the conclusion that the power levels are decentralized allocated. In the project, successive interference cancellation (SIC) is selected as the support of the optimal power decentralized distribution. While doing the project, we consider the throughput maximization problem of a 2-user system under different rate and power constraints. The optimization is also under the situation of collisions of two users. From the result of the optimization of the throughput, it is quite clear that the throughput of ALOHA-type systems is improved if SIC is implemented at the receiver. To verify the performance in a more realistic way, a real-time simulation on both conventional ALOHA system and the system with SIC support is implemented. The simulation results also agree with the hypothesis ones.