Frequency reuse during relay transmission for two-hop IEEE 802.16j relay networks

Frequency reuse during access zone is widely adopted for throughput enhancement in IEEE 802.16j relay networks. Since areas covered by relay stations (RS) or base station (BS) may overlap, some mobile station (MS)s on the border between two neighboring transmitting stations (RS or BS) using an identical frequency band may suffer severe interference or outage. This co-channel interference within the cell degrades fairness in QoS among MSs as well as system throughput. In this paper, we propose to introduce frequency reuse scheme during relay zone as well as during access zone. Our scheme increases the efficiency of resource without much overhead. The improved efficiency is used to alleviate the above co-channel interference. MSs, which are interference-prone if served during access zone, are now served during relay zone using our proposed frequency reuse scheme to be used along with directional antennae. We show our scheme achieves higher system throughput with higher fairness level in QoS, outperforming previous schemes.