异构协作网络中采用令牌漏桶的多接入业务分配算法

A Token Bucket Based Traffic Allocation Algorithm for Multi-Radio Access System in Heterogeneous Collaboration Networks

针对异构协作网络中业务突发性引起拥塞的问题,提出一种基于令牌漏桶的多接入业务分配(TATB)算法。该算法首先通过在城域网中加入令牌漏桶来限制和平滑业务的突发性,将令牌漏桶看作一个离散时间的马尔科夫链,得到第1跳的平均传输时延,将第2跳看作服务时间服从指数分布的队列模型,得到系统的平均时延,然后以系统平均时延最小化为目标,以队列的稳定性作为约束条件,构建了优化问题,并证明该问题为凸问题,最后通过拉格朗日对偶分解,采用牛顿投影法调整业务的分配,用梯度投影法调节分配业务的价格因子。仿真结果表明:TATB算法不仅可以获得更小的系统时延,而且需要迭代的次数少,减少了系统的信令开销,便于实现;TATB算法的时延仅分别是未考虑令牌漏斗算法、负载均衡算法和基于路径等分配算法时延的28%、27%和24%。

A traffic allocation scheme based on token bucket （TATB） for multi-radio access system is proposed to manage the congestion problem caused by burst traffic in heterogeneous collaboration networks.The token buckets are used in the wireless metropolitan area networks to limit and to smooth the burstiness of traffic.The token buckets are regarded as a Markov chain of discrete time to compute the average delay of first-hopes and the second-hopes are considered as a queue model with the service time following an exponential distribution,so that the system average delay can be obtained.Then,a constrained optimization problem is formulated to minimize the system delay with the constraint of queue stability,and it is proved that the problem is convex.The Lagrangian dual decomposition methodology and the Newton projection algorithm are used to obtain the traffic allocation and the gradient projection algorithm is used to get the price of allocated traffic.Simulation results show that the TATB algorithm is low overhead and easy to implement,and that less delay is obtained.Moreover,the delay performance of the TATB algorithm is only about 28％,27％ and 24％ the delay performance of the non-TATB algorithm,the load balancing approach and the equal traffic allocation in different path.