Abstract: Wireless multi-hop relay systems play an important role in upcoming broadband wireless networks like WiMAX. Such relay can be used either to increase a cellís capacity or expand a cellís coverage, all at much lower cost compared to the alternative solution of using more Base Stations (BSs). The IEEE 802.16j is an amendment to the IEEE 802.16e standard, which introduces the multi-hop relay concept into existing point to point mode of communication. IEEE 802.16j mobile multi-hop relay (MMR) standard introduces two types of relays, transparent and non-transparent relays. This work has focused on studying the impact of having transparent relay stations on overall system throughput in an MMR WiMAX network and studying the impact of a number of transparent relay stations on overall system throughput in an MMR WiMAX network by implementing a transparent relay station concept in QualNet simulator. Simulation studies have been carried out using the QualNet simulator by considering the throughput as performances metric for constant bit rate (CBR) and variable bit rate (VBR) traffic individually. From the simulation results it is observed that introducing transparent relay stations in the MMR WiMAX network enhance the performance of the network. Furthermore, it was found the performance enhancement exclusively depends on its deployment. Much further work is necessary to realize useful gains from these systems.
Keywords: 802.16j MMR, Transparent Relay, Performance, QualNet.