An efficient uplink transmission scheduling algorithm with reduced interference and outage for IEEE 802.16j relay networks

Uplink scheduling for relay stations in mobile multi-hop relay network has not been widely addressed in the literature under common belief that downlink traffic overwhelms uplink traffic. Recently, data traffic from user created content (UCC) is rapidly growing with a potential to create a huge amount of uplink (UL) traffic. Overlapped resource allocation in uplink transmission allows MSs attached to different RSs can reuse the same frequency band to increase the network throughput. However, the uplink traffic from MSs located on the boundary between two neighboring RSs may cause interference to each other RS. The interference degrades the uplink throughput or even leads to service outage for MSs located on the boundary, resulting in poor fairness in QoS among subscribers. We propose an uplink transmission scheme with reduced interference. We reduce the interference by grouping MSs in such a way the uplink transmission from the MSs in a group do not interfere each other at the receiving RSs. Simulation results show that the proposed scheme removes service outage by 61.5% and increases average throughput by 13.3% compared with a simple overlapped resource allocation scheme(similar to the overlapped resource allocation scheme for downlink transmission). In terms of fairness, the proposed scheme excels by 38.7% the simple overlapped scheme.