Optimization of Frame Structure for WiMAX Multi-hop Networks

To enhance the system throughput and to extend coverage of IEEE 802.16 networks, relay stations can be implemented. If a user station is attached to the base station (BS) through several relays stations (RS), a multi-hop communication occurs. To enable multi-hop communication, the IEEE 802.16j standard proposes two approaches how RSs can be implemented into the network. The first approach groups BSs and several RSs into a multi-frame with repetition of relay zones. In the second approach, the BS schedules several relay zones in one frame. While the first approach causes long packet delays, the second approach has high requirements on RS’s processing capabilities. This paper proposes an optimized frame structure that allows using second approach whilst the requirements on RS’s processing time are still kept in reasonable range. The obtained simulation results indicate that packet delays in downlink and uplink direction can be significantly reduced.