Handover rate based dynamic guard bandwidth allocation method for call admission control in IEEE 802.16j Mobile Multihop Relay networks

IEEE 802.16j MMR (Mobile Multihop Relay) networks are developed to extend the coverage area and enhance the throughput of IEEE 802.16 networks. Call Admission Control (CAC) is an important research issue related to these networks. In this paper, a novel dynamic guard bandwidth allocation method is proposed for CAC in IEEE 802.16j networks; the guard bandwidth allocated at a station depends upon the handover rates from its neighbors and at its descendent stations. A bandwidth wastage prevention policy is proposed to utilize the unused guard bandwidth to fulfill the requests of lower priority calls and eventually to improve the bandwidth utilization of the network. Based on the total amounts of the guard bandwidth received by the lower priority calls, a novel bandwidth borrowing scheme is proposed. A Markov model is developed to analyze the performance of the proposed CAC method; analytical handover call dropping probabilities and new call blocking probabilities of various service classes are obtained using the proposed Markov model. Simulation experiments are conducted to compare the performance of the proposed CAC method with a fixed guard bandwidth based CAC method. The proposed method showed superior performance than the fixed guard bandwidth based method. Also, the simulation results are compared with the analytical results.