An end-to-end QoS aware greedy distributed scheduling framework for WiMAX mesh networks

In this paper, we propose a greedy framework for distributed scheduling in the IEEE 802.16 MeSH mode, which uses a novel “End-to-end QoS aware bandwidth Reservation Protocol” (EQRP) to provide end-to-end QoS guarantee to intramesh flows. The proposed framework provides an efficient and integrated solution to QoS aware routing and call admission control in distributed WiMAX mesh networks. The framework does not rely on any special node for resource management which makes it more scalable and robust to node failures. To save expensive control overheads, EQRP learns from previous bandwidth reservation failures to maintain a rank list of next hops for every destination and uses the “Greedy Forwarding” algorithm to do bandwidth reservation using slot information from only two hop neighbor routers'. We compare EQRP with Race Free Protocol (RFP) and evaluate its performance with extensive simulations in ns2. Simulations show that for static WiMAX mesh network, the “Greedy Forwarding” algorithm used by EQRP admits approximately 10% more VOIP calls. For a random topology of 25 mesh routers, the aggregate signaling overhead generated by EQRP at a high call arrival rate of 1/2000 (calls/milli-seconds) is 76% less than that generated by RFP. In comparison with RFP, EQRP took 200 milli-seconds less average call setup time.