A mobility management protocol for multi-hop relay networks

IEEE 802.16j Multi-hop Relay (MR) task group has been chartered in order to adapt the promising advantages of multi-hop wireless access in terms of capacity, throughput, and coverage to WiMAX systems. In the MR networks, due to introduction of the RSs (Relay Stations), MS (Mobile Station) mobility management for the provision of seamless handover becomes more challenging compared to the traditional one defined in IEEE 802.16e-2005. In this paper, a systematic approach to classify the handover scenarios for de-centralized MR networks when using high capability RSs will be presented. Then, we define the MAC handover procedure and corresponding MAC management messages over multi-hop relay links. The simulation results show that the proposed handover protocol not only reduces the MAC management message overhead transferred on the wireless links compared to IEEE 802.16j/D1, which is the current standard for MR networks, but also performs the rapider and more secure MS handover than IEEE 802.16e and IEEE 802.16j/D1.