Wireless Mesh Network Channel Mac Protocol Research

With the development of WMN and the ever-growing popularity of personal data communication, people want to have a higher demand on wireless network's bandwidth and coverage. More and more users have opportunity to access MAP, the network traffic becomes bigger and bigger. A lot of researchers want to found a solution for the bottleneck problem at MAPs and provide different services for different business. The use of multi-channel technology, and improve the performance of MAC protocol is an effective way to solve the QoS needs of different businesses.IEEE 802.11s is an amendment of IEEE802.11 standard for Mesh Networks. It improves the IEEE 802.11's MAC protocol, and provides different services for different businesses by using IEEE 802.11e standard's QoS enhancements. The background of research is IEEE 802.11s Wireless Mesh network. This paper discusses the bottleneck problem at MAPs and QoS assurance for different business under heavy load network,This paper has analyzed some existing multi-channel MAC protocols. In light-load or moderate-load network, they can do well in coordinating nodes accessing channel for data communications and have some good performance on network throughput, delay and so on. But they don't have a proper solution to assign channel for every nodes when the network becomes heavy load. This paper designs a new multi-channel MAC protocol (NPBM-MAC), it uses a global node communication state table for channel assignment. Thereby the channel conflict probability has been reduced. At the same time, this protocol distinguishes different services by node priorities and business priorities. It can meet the different businesses'QoS requirements and ensure the traffic of audio/video businesses can be prioritized.NPBM-MAC protocol can not solve the frequency interference problem between BSS, which belongs to different MAP. This paper provides a new frequency assignment scheme—LLBFA, it is based on nodes'location information and network load. This scheme can assign frequency from the overall situation according to network topology. So, it can resolve the problems pointed above. At last, this paper does some simulations by OPNET. The results shows that NPBM-MAC protocol and LLBFA can effectively reduce frequency interference problems, improve the transmission delay and network throughput. It is an effective solution to solve the bottleneck problem at MAPs/MPPs in the heavy load network, so that it can ensure the QoS requirements by video streams and other applications with large bandwidth demand.