| 摘要: |
| 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%. |
| 关键词: 多跳无线网络 隐藏节点问题 IEEE 802.11 DCF DCCFMA 双信道 |
| DOI： |
| 分类号: |
| 基金项目:Supported by the National High-Tech Research and Development Plan of China under Grant No.2005AA121130 (国家高技术研究发展计划(863)) |
|
| Collision Free MAC Protocol for Multi-Hop Wireless Networks |
|
ZHANG Ke-Wang,ZHANG De-Yun,DU Jun
|
| Abstract: |
| 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 in multi-hop wireless network
and proposes an MAC protocol named double channel collision free media access protocol—DCCFMA to solve the
hidden nodes problem. DCCFMA is a dual channel MAC (media access control) protocol, receiver adjusts the
transmitting power of the control channel according to the signal power received from the transmitter so as to cover
all hidden nodes around the receiver. Simulation results show that DCCFMA solves hidden nodes problem better
than RTS/CTS (ready-to-send/clear-to-send) handshakes and achieves 24% additional network throughput as
compared to that of 802.11 DCF. |
| Key words: multi-hop wireless network hidden nodes problem IEEE 802.11DCF DCCFMA dual channel |
