Load-aware channel hopping protocol design for mobile ad hoc networks

Utilizing multiple channels improves spatial reuse and reduces collision probability, which enhances network throughput. There exist many multi-channel MAC protocols; however, most of them suffer from either higher hardware cost (requiring more than one transceiver for each node) or control channel bottleneck. Some channel hopping multi-channel protocols achieve pretty good performance in some situations. Unfortunately, they fail to adjust their channel hopping mechanisms based on varied loads. This may lead to performance reduction. There are many challenges for designing a multi-channel MAC protocol. How to solve the multi-channel-specific problems, such as channel assignment problem, the multi-channel hidden terminal problem, and the missing receiver problem, is essential. In this paper, we propose a Load-Aware Channel Hopping MAC protocol (LACH) that solves all the problems mentioned above and enables nodes to dynamically adjust their schedules based on their traffic loads. Besides the load awareness feature, several other attractive characteristics can also be found in the LACH protocol: (1) Each node is equipped with one half-duplex transceiver. (2) Each node´s initial hopping sequence is generated through its ID. Knowing neighbor nodes´ IDs, a node can conduct their initial channel hopping sequences without control packet exchanges. (3) Nodes are evenly distributed among available channels. Through simulations, we verify the superiority of the proposed LACH.