定义了Ad Hoc网络中能够反映碰撞和节点竞争的无线可用带宽。被考察节点通过CSMA/CA协议将测量时间内邻居节点数据分组中的网络分配矢量以表的形式记录在自己的路由缓存中,对测量时间内同一节点的网络分配矢量叠加,并减去被考察节点退避的时间,最终计算出测量时间内当前节点的可接入信道时间。使用可接入信道时间占测量时间的比例来计算可用带宽。仿真在竞争节点发送速率变化的情况下测量了被考察节点的可用带宽,随后被考察节点也改变发送速率来验证测量所得的可用带宽。数值结果表明,所使用的可用带宽测量策略较为准确,并能充分反映节点之间的碰撞。
A new definition of available bandwidth in Ad Hoc network to reflect the collision and contention between nodes is given. The investigated node obtains the NAV information of its neighbors within the measurement duration through CSMA/CA mechanism and stores the information into its routing buffers. To the node sending several packets during a single measurement duration, the sum of NAV values can be computed. The available bandwidth of the investigated node is obtained by calculating the ratio of its channel accessible time to the measurement duration, which should subtract the sum of NAV values of its neighbors and the backoff time itself from the measurement duration. Simulation shows the proposed scheme is accurate and can completely reflect the collision and contention between nodes.