基于动态带宽预留和带宽降级的呼叫准入控制算法

提出了一种适用于无线／移动网络的呼叫准入控制方案，该方案包括了动态带宽预留与带宽降级算法（BDA）2个部分．根据切换呼叫的准入结果实时地调整切换呼叫预留带宽，在限制切换中断率（HDP）的同时，尽可能降低呼叫阻塞率（CBP）．在对未来带宽需求预测的基础上，所提方案采用不同的BDA触发方式，使得系统在处理负荷与带宽利用率之间取得平衡．BDA可综合考虑多种因素，包括业务优先级、公平性、呼叫持续时间、带宽调整波动性以及降级呼叫比例等，通过合理地设置带宽需求满足度、带宽波动幅度，以确保BDA的公平性和限制带宽调整的波动性．仿真结果表明，在2000个仿真时段内，所提方案的HDP均值较同类方案稍高，但仍然控制在阈值范围之内，较之其他方案，它的CBP均值和BDA触发次数均值均比较低．

Call Admission Control Algorithm Based on Dynamic Bandwidth Reservation and Bandwidth Degradation

A call admission control scheme,named MCBDACAC,is proposed for wireless/mobile network based on dynamic bandwidth reservation and bandwidth degradation algorithm(BDA).MCBDA-CAC adjusts the reservation bandwidth for handoff calls in terms of the results of admitting handoff calls,confines handoff dropping probability(HDP) under a predefined threshold,and decreases call blocking probability(CBP) as low as possible.In addition,based on the estimation of the bandwidth demand in the next time interval,different BDA trigger modes are adopted to achieve the tradeoff between the system operation complexity and bandwidth utilization ratio.The proposed BDA takes many factors into account,such as service priority,fairness,call duration time,bandwidth fluctuation,and degradation call number ratio.To guarantee the fairness and to limit bandwidth fluctuation,two QoS parameters,named bandwidth satisfactory degree and bandwidth fluctuation degree,are proposed.The performance simulation shows that during 2000 simulation intervals,the average HDP of MCBDA-CAC is higher slightly than that of the similar schemes,but is still confined within the threshold.In addition,the average CBP and the average BDA trigger numbers are all lower than those of the similar schemes.