| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 95 === Nodes in Wireless Mesh Networks (WMNs), like in ad hoc networks, work not only as a host but also as a router. Packets are forwarded between nodes toward a gateway in a multi-hop way. Multiple non-overlapping channels specified by the IEEE 802.11 Wireless LAN standard can be used simultaneously to increase the aggregate bandwidth. However, multi-channel multi-interface protocols may incur a type of hidden terminal problems. We found that the existing multi-channel multi-interface IEEE 802.11 Medium Access Control (MAC) protocols have room to be improved in the approach to the multi-channel hidden terminal problem, where a static waiting time scheme is used. In this paper, we propose an enhanced MAC protocol with a hybrid channel assignment strategy and a dynamic waiting time scheme for multi-channel multi-interface WMN to avoid the multi-channel hidden terminal problem. The proposed dynamic waiting time scheme assigns waiting time for each channel by using the information of nearby traffic load to utilize the available bandwidth and reduce the end to end delay. From simulation results, we show that the proposed MAC protocol can increase system throughput and decrease packet end to end delay.
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