通过速率分配将单数据流拆分到多网络可实现高速协作传输,但对无线随机接入网而言,这相当于增加了竞争传输的用户数,会导致接入碰撞率和平均等待时间增大.为此,文中提出了一种基于无线随机接入代价函数的协作传输速率分配算法,用信道利用率建立的价格函数来描述接入时间代价,按照以最小接入代价换取最大吞吐量收益的原则对速率分配进行数学建模,并证明了该速率分配问题是一个凸优化问题,还根据拉格朗日乘数法推导出了显式解.仿真结果表明:该算法可根据网络状态和信道效率进行网络选择和资源调度,在接入时延和分配公平性上进行了折衷;同时可避免接入重载随机接入网,从而提高接入效率.
In wireless random access networks,high-speed cooperative transmission can be implemented via the rate allocation that distributes the traffic flow to heterogeneous networks.However,both the collision probability and the average waiting time may increase with the number of competitive hosts.In order to solve this problem,a rate allocation algorithm based on the pricing function of cooperative access to the network is proposed,which describes the access time cost with the pricing function based on the channel utilization and models the rate allocation according to the principle of achieving the maximum total network payoff with the minimum access cost.The above-mentioned rate allocation problem is proved to be a convex optimization one and the explicit solution to the problem is obtained according to the Lagrange multiplier method.Simulated results show that the proposed algorithm helps to select the access networks and distribute the traffic to networks according to both the network status and the channel efficiency,and that it makes a trade-off between the access delay and the fairness.Moreover,it avoids the access to heavy-load random access networks,thus increasing the access efficiency.