Research On Ad Hoc Network Access Algorithm Based On Service Priorities

In recent years,the Ad Hoc network has gradually developed its research direction into aviation Ad Hoc networks,vehicle networks,intelligent Ad Hoc networks,and sensor networks.There are more and more researches in practical fields,both in the field of aviation Ad Hoc networks and vehicle networks,and there are demands for providing quality of service(Qo S)guarantees.And the use of priority mechanisms is a great way to guarantee the quality of service.Therefore,this paper proposes an access algorithm that uses a priority mechanism to guarantee the service quality of high-priority services and at the same time to perform fair bandwidth allocation for the same priority service.In order to ensure a fair distribution of bandwidth,a weighted fair queue scheduling algorithm is used for queue scheduling,and a dynamic update rule for weights is introduced to make it better adapt to changes in network conditions.Priority-based access algorithms generally set different backoff durations for services of different priorities.This paper is different from the modification method of the competition window in the general solution method.The influence of the priority and the weight of the service flow is directly considered in the calculation of the backoff duration,so as to ensure that the backoff duration of different priority services is different.Firstly,this paper introduces the research status of Ad Hoc networks and Media Access Control(MAC)protocols that support Qo S.Then it studies the key issues of MAC protocol and the backoff mechanism of 802.11 protocol.The weighted fairness rules and the common queue scheduling algorithms are introduced.Based on this,the design idea of priority-based access algorithm is given.First of all,it introduces the start time fair queuing algorithm.Next,the dynamic weight update mechanism was introduced and a theoretical fairness analysis was conducted.Finally,the calculation rules for the back-off duration are introduced to complete the design of the entire access algorithm.At the end of this paper,the specific implementation details of the NS2-based access algorithm are introduced first,and then its ability to guarantee the high-priority service quality and the ability to allocate the bandwidth fairly is simulated and the corresponding conclusions are obtained.