Path metrics for lower throughput fluctuation for video streaming service in wireless mesh networks

The video streaming service over Wireless Mesh Networks (WMNs) is an attractive feature for live streaming and video conversation when disaster occurs. The path construction with the conventional metrics e.g., throughput, latency, or packet loss rate, suffers from the repeated waiting time due to the CSMA/CA since paths are concentrated on nodes with good metric. As a consequence, it brings about throughput fluctuation of video streaming service. We propose two metrics that reflect on the magnitude of CSMA/CA interference around a node in order to select a path that the throughput of video streaming session will get stable. The first metric is calculated from the number of received Request To Send (RTS)/Clear To Send (CTS) frames. Since the number of RTS/CTS reflects on the frequency of the packet transmission around a node, a source node can chooses a path which does not make a node waiting for constant time due to the CSMA/CA on the existing path that might use streaming service. The second metric uses the number of neighbor nodes and we set the larger metric value as more nodes exist. The idea comes from the fact that a node which has few neighbor nodes does not much interfere other established paths. The proposed metrics can be easily installed into Hybrid Wireless Mesh Protocol (HWMP) which is a de facto standard path selection protocol defined in IEEE802.11s. We show that the proposed metrics can achieve lower rate of throughput fluctuation than that of conventional metric by using the networks simulator Qualnet.