Research On The Interference-aware Routing Metrics For Wireless Mesh Networks

Recently，wireless communication and mobile Internet are becoming parts of daily life.The rapid development of wireless communication technology can provide more convenientInternet services. Wireless mesh networks have been regarded as one of the most potentialwireless network technologies due to the capability of higher rate, higher capacity and strongscalability.With the development of wireless communication technology, interference is always themain factor limiting the network performance. Current researches on network optimizationscheme are all for the purpose of reducing interference and enhancing network capacity inwireless mesh networks. With the help of interference model, interference-aware networkoptimization schemes can allot the network resources reasonably, which can enhancenetwork capacity. As one of the most important network optimization schemes,interference-aware routing technology utilizes routing metrics to aware interference andselects paths with smaller interference in wireless mesh networks, which improves networkperformance effectively. Consequently, it is important to research how to design interferencemodel and interference-aware routing metric for wireless mesh networks. This paperaddresses the problem of route selection in wireless mesh networks.Expected transmission count (ETX) adopts packet delivery ratio (PDR) as arepresentative metric of wireless link quality assessment. However, PDR measured by thebroadcast-based probe method is affected by the size, number and transmission rate of probepackets, which influences the metric accuracy. In this paper, improved expected transmissioncount (iETX), a new routing metric of interference-aware link quality, is proposed forwireless mesh networks. Dispensing with traditional broadcast-based probing method, iETXuses regional interference model to obtain PDR. Regional interference model is built uponthe relationship between signal to interference plus noise ratio (SINR) and PDR, whichcontributes to the improvement of metric accuracy and reduction of network overhead. iETXcomprehensively considers the effects of interference and link quality and minimizes theexpected number of packet transmissions required for successful delivery, which helps find apath with minimum interference and high throughput. Compared with ETX, simulationresults show that iETX can improve the network performance, such as networks throughput,delay.In order to better reduce the influence of interference, another new routing metric ofexpected back-off time (MEBT) is proposed for wireless mesh networks in this paper. Thisrouting metric takes channel contention interference into consideration, which is based onthe average back-off time and iETX mentioned above. MEBT utilizes iETX to obtain expected retransmission count, and aware channel contention interference by computingnode’s average back-off time. MEBT adopts the passive measurement method for measuringparameters, which can also reduce the network overhead. MEBT combine iETX and theaverage back-off time, which can aware physical interference and channel contentioninterference uniformly and choose a path with minimum interference. Simulation resultsshow that MEBT’s superiority in reducing the influence of network interference.The main works of this paper provide reference for the research on theinterference-aware routing technology in wireless mesh networks.