面向多跳无线网络的无冲突MAC协议

多跳无线网络中隐藏节点导致节点之间的冲突频繁、数据重传率高、网络吞吐量下降.而802.11 DCF 中的RTS/CTS(ready-to-send/clear-to-send)机制不能有效地防止隐藏节点,特别是随着网络中节点通信速率的提高,由 于节点的信噪比要求也相应提高,接收节点受到更大范围内隐藏节点的干涉,RTS/CTS 机制防止隐藏节点的效率急剧降低.首先,在考虑网络积累干涉以及环境噪音的情况下分析了多跳无线网络中的隐藏节点问题.然后,提出一种双信道无冲突MAC(media access control)协议DCCFMA(double channel collision free media access).DCCFMA 协议采用双信道结构,接收节点根据数据信道中发送节点的信号强度动态调节控制信道的发射功率,以完全覆盖接收节点周围所有的隐藏节点,保证接收节点在接收过程中不受干涉.DCCFMA 协议能够有效地解决多跳无线网络中的隐藏节点问题.仿真结果表明,与802.11DCF 相比,DCCFMA 机制下的平均网络吞吐量增加了24%.

Collision Free MAC Protocol for Multi-Hop Wireless Networks

Collision rate increases significantly with the appearance of hidden nodes in multi-hop wireless network, which results in unsuccessful transmissions and leads to performance degradation of the network. The RTS/CTS handshakes of 802.11DCF can not eliminate hidden nodes, and the situation becomes worse when the nodes are equipped with higher speed wireless devices, which require higher signal to interference and noise ratio (SINR) for successful reception. This paper analyzes the prevalence of hidden nodes i...