Study And Improvement On The IEEE 802.11s-based HWMP

Recently, WMN (Wireless Mesh Network) has become an object of universal attention in the field of telecommunications. WMN is a new networking model which is able to transmit and forward data packets via wireless mesh nodes towards the destination node. As one of the representative standards, the IEEE 802.11s protocol solves the coverage problem of traditional WLAN. HWMP, the path selection protocol applied in 802.11s, is the basis of effective data transmission and mobility support in a 802.11s network. Therefore, a further research on HWMP is significant to the application of 802.11s and WMN.This paper firstly introduces the most widely used wireless mesh network standards, and then analyzes the principle and features of the routing protocol applied in these standards. Next, a detailed description of HWMP is made.On this basis, a common phenomenon in 802.11s network, Ping Pong effect, is introduced in this paper. The basic cause of this effect and its influence on the network throughput performance and link state is analyzed using NS-3 simulation platform. After knowing the properties and effect of Ping Pong effect, a detection and utilization mechanism of this effect is proposed. Simulation results show that this mechanism can optimize the network performance self-adaptively according to the variation of network topology. Moreover, a further discussion is made upon the influence of the instability. And the analysis result indicates that the relationship between instability and throughput performance can be characterized as an M-shape curve. Finally, an improved mechanism designed for static networks is proposed. Experiment results show that this method play a positive role in the improvement of network performance.