Research On Routing Metrics In Wireless MESH Network

Wireless Mesh Network (WMN) is a kind of Mobile Ad Hoc Network demanding high throughput. It's characterized by high data rate,easy expending,low primary cost,stable performance and so on. Wireless Mesh Network can connect different kinds of the current Wireless Networks including, mobile cellular network, wireless sensor network, WLAN, WiMAX, WiFi and brings the ubiquitous wireless mobile broad-band network connection to customers. WMN needs to support different kinds of data services. It's very complicated and critical to offer proper QoS support to different kinds of data services. Designing a Routing Metric which identifies high thoughput path is important for QoS routing protocol in WMN.Nowadays many cities across the world have already deployed WMN, but the performance of these networks today leaves much to be desired. The main reason to poor performance is that current routing protocol can't identify high throughput path,and the chief culprit is the underlying interference and congestion in wireless network,that's to say the routing metrics of routing protocol in WMN haven't been accurately measuring the link quality. Most of the current routing metrics is basic on ETX, some related researches have pointed out that ETX can't accurately reflect link quality under interference, however they haven't thoroughly analyzed the essential problems of ETX and given the effective solution.We first summarize and analyze the designing method to the current routing metrics.It is separated into two types,one type is basic on ETX routing metrics,another type is basic on the method of cross-layer design. Then we deeply analyze the reliability of ETX. Combining with the simulations to ETX under congestion on ns-2, we find out the radical reasons to the unreliability of ETX. Thus, we deny the design method base on ETX and propose that cross-layer design is the effective and practical method to handle the problems of metrics based on ETX.Finally, we design a low interference,congestion,end-to-end delay routing metric(LicdRM) on Qualnet5.0 adopting the concept of PARMA and making use of the cross-layer information from APP., MAC and PHY. The Simulation results demonstrate that LicdRM can acurratelv avoid paths with serious congestion and find path with low end-to-end delay, as a result improving the throughput of the network.