A Study of Wireless Mesh Network Routing Protocols for Push-to-Talk Traffic

Wireless mesh networks (WMNs) are becoming well-known as a new broadband Internet access technology through multihop transmission nowadays. With the tremendous popularity of the group communication, such as Push-to-Talk service, the need to deliver the traffic of push-to-talk over WMNs is becoming important. Since the push-to-talk traffic over WMNs is delay-sensitive traffic, a proactive routing protocol that keep routes continuously updated is ideally best-suited protocol. Among the proactive routing protocols, a tree-based routing (TBR) protocol is a viable routing protocol for WMNs because traffic that is directed to/from a wired network can be well-handled via a portal (a root). However, the performance of TBR protocol can be degraded rapidly when the number of group talking increases, which also leads to the intra-mesh traffics increases in the network. To mitigate this problem, we proposed a centralized tree-based routing protocol, which enables the root to provide the best metric route for intra-mesh traffics. In other words, the proposed protocol can disperse the intra-mesh traffics around the root when an overwhelming traffic volume occurred. Our simulation studies reveal that the proposed protocol outperforms both AODV and TBR protocols in terms of packet delivery ratio, average end-to-end delay, and data throughput as the number of active users becomes larger.