Research On MAC Protocol Of Police Private Packet Wireless Access Network And Schedule Algorithm Design

Police private packet wireless access network not only provides communicationsof integrated services with QoS guarantee, but also can let the mobile terminals movefreely.The most severe problems encountered in wireless networks are the limitedfrequency resources and the fast-varying wireless channel. So, how to provide reliablecommunications with QoS over wireless channels is a considerable issue.First, this paper proposes a MAC protocol structure for both CBR and VBRtraffics with QoS requirements. According to the correlation of video traffic streams,the algorithm allocates the bandwidth based on the predicted arriving rate of thestreams. In this way, the transmission delay is reduced, and the throughput of thenetwork increases.Though the proposed algorithm can provide good QoS for video streams, thealgorithm is designed for characteristics of video streams only, which makes itunsuitable for traffics of other types. Thus, this paper then presented a modifiedscheduling algorithm based on the utilization and the overloads of network. Itcalculates an efficient weight factor for each traffic and the factor is afterwards usedto allocate remainded network bandwidth.In the last part, both algorithms are simulated for comparison. The resultsindicate that both algorithms improve the performance of the networks, in which theQoS of different traffics can be guaranteed. Also, the computational complexity ofboth algorithms is very low, so they can be easily implemented for practical use.