无线信道固有的特点,使得无线局域网面临比有线局域网更多的困难。发展合适的介质访问控制协议(MAC)是无线局域网一个关键,而其中退避算法又是 MAC 协议考虑的重点。本文介绍了退避机制在 IEEE802.11MAC 层中的作用,指出了二进制指数退...无线信道固有的特点,使得无线局域网面临比有线局域网更多的困难。发展合适的介质访问控制协议(MAC)是无线局域网一个关键,而其中退避算法又是 MAC 协议考虑的重点。本文介绍了退避机制在 IEEE802.11MAC 层中的作用,指出了二进制指数退避算法存在的不足。对当前已提出的多种典型退避算法进行了介绍,对各类算法的设计思想进行了分类。最后阐明了退避算法研究的发展趋势。展开更多
To deal with hidden nodes in ad hoc network, we take throughput as the metric to evaluate the performance of network. Firstly, we modeled the MAC layer of ad hoc network based on 802.11 DCF without the existence of hi...To deal with hidden nodes in ad hoc network, we take throughput as the metric to evaluate the performance of network. Firstly, we modeled the MAC layer of ad hoc network based on 802.11 DCF without the existence of hidden nodes. By means of the proposed model, we evaluated the throughput performance of DCF in multi-hop wireless networks. Secondly, we performed simulations to validate this model. The outcome of comparison is that there exists much difference in throughput between the model and the simulation. For reducing this difference, we modified the model by involving hidden nodes under the condition that the AODV route protocol was chosen, and analytically analyzed the influence of hidden nodes on theoretical throughput. At last, we validated the accuracy of this model by comparing the analytical results with simulation results.展开更多
文摘无线信道固有的特点,使得无线局域网面临比有线局域网更多的困难。发展合适的介质访问控制协议(MAC)是无线局域网一个关键,而其中退避算法又是 MAC 协议考虑的重点。本文介绍了退避机制在 IEEE802.11MAC 层中的作用,指出了二进制指数退避算法存在的不足。对当前已提出的多种典型退避算法进行了介绍,对各类算法的设计思想进行了分类。最后阐明了退避算法研究的发展趋势。
文摘To deal with hidden nodes in ad hoc network, we take throughput as the metric to evaluate the performance of network. Firstly, we modeled the MAC layer of ad hoc network based on 802.11 DCF without the existence of hidden nodes. By means of the proposed model, we evaluated the throughput performance of DCF in multi-hop wireless networks. Secondly, we performed simulations to validate this model. The outcome of comparison is that there exists much difference in throughput between the model and the simulation. For reducing this difference, we modified the model by involving hidden nodes under the condition that the AODV route protocol was chosen, and analytically analyzed the influence of hidden nodes on theoretical throughput. At last, we validated the accuracy of this model by comparing the analytical results with simulation results.
