System Level Performance of Multiuser Diversity in Cooperative Relay Based OFDMA Networks

Abstract

In cooperation relay system, two relay stations transmit cooperatively for the relay link users, and the relay link users receive signal by maximal ratio combining. The traditional multiuser scheduling algorithms, Max C/I algorithm for system throughput maximization and proportional fairness (PF) algorithm for user fairness, are extended into the DF cooperative relay systems. The simulation results show that the Max C/I algorithm obtains great multiuser diversity gain and cooperation diversity gain. In the Max C/I algorithm, deploying more RSs in the cell has a constructive effect on the multiuser diversity. However in PF algorithm, adding more RSs in the cell has an adverse effect on the multiuser diversity. Varying number of users has big impact on the user fairness performance of Max C/I, but the user fairness of PF is mainly affected by the RS number.

Link-Level Performance Evaluation of Relay-Based Wimax Network

“…Likewise (9) Where b k,r,m represent k th subchannel allocated to user m using RSr (relay station r) using the second hop link [52]. Estimating the capacity of direct link in the first time slot using Shannon's formula is given by:…”

“…To determine the average data rate of user on the relay link, we divide the amount of data received by the time required to receive it [52]. 1 .…”