为解决无线网络中长传播时延所带来的信道资源利用率低的问题,提出一种基于快速预约按需发送(FRODT)的媒质接入控制(MAC)协议。该协议利用中心控制节点(CCN),在两个信道上安排各节点的分组预约和发送,保证了各节点可以在一帧中无碰撞地发送一个或多个业务分组,并且各节点通过一次握手预约即可完成整个通信会晤的业务分组发送,从而减少了由于握手而产生的过多传播时延,大大提高了多址性能。仿真结果表明:FRODT协议比基于集中调度的MAC(CSMAC)协议的信道吞吐量高,平均分组接入时延小,平均分组丢弃率低,尤其适用于长传播时延环境,具有较好的多址性能。
To solve low channel utilization problem caused by long propagation delay in wireless networks, a fast reservation on-demand transmission (FRODT) medium access control (MAC) protocol is proposed. In the protocol, a central control node (CCN) is used to schedule channel reservation and packet transmissions to ensure that each node can transmit one packet or multiple packets without packet collisions in a frame, and accomplish its communication session only by one handshake. Therefore, it can reduce the adverse effect of long propagation delay caused by handshakes, and then greatly increase multiple access performance. Simulation results show that FRODT protocol outperforms the centralized scheduling-based MAC (CSMAC) protocol in terms of throughput, average packet access delay and packet dropping rate, especially in the presence of long propagation delay.
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