Summary: | 碩士 === 淡江大學 === 資訊工程學系碩士班 === 102 === Distributed Coordination Function (DCF) is a well known MAC protocol for single channel wireless ad-hoc networks. However, hidden terminal and false blocking problems may happen if DCF is directly applied to multi-channel environments. There are some past researches focus on these problems. But the control channel congestion problem still exist to affect the network performance and decreases the channel utilization. As a result, we propose a Multi-group Multipipeline Multi-channel MAC protocol (3M MAC) for wireless multi-channel ad-hoc networks to avoid multi-channel hidden terminal and false blocking problems. 3M MAC divides a task into several sub-tasks. Each sub-task is transmitted sequentially on all channels. Under this pipeline-like scheme, we further analyze the impact of the channel switch time and DATA packet size on network performance. The channel leak problem will happen when the DATA size is too short. The main concept of 3M MAC is to divide channels into groups to alleviate the channel leak problem and channel congestion problem. Finally, we compare 3M MAC with well-known multi-channel MAC protocols. Simulation results show that 3M MAC outperforms against the other multi-channel MAC protocol in network throughput, transmission delay and channel utilization.
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