Distributed medium access control for multiple hop tactical networks

In mobile ad-hoc networks (MANET), traffic coordination is a constant challenge. Node topologies and transmission patterns are continuously changing, making wireless communications complicated and difficult to maintain. Adaptive transmission scheduling must be implemented in order to relieve the stresses placed upon a MANET by packet collisions. In this paper, we identify the impact of hidden nodes in a multiple hop network with reference to a new shift in warfare style. We introduce Distributed medium access control (DMAC), a distributed TDMA channel access protocol designed with low physical requirements (single-channel, half-duplex radio with clear channel assessment) that manages outgoing traffic based on traffic type. By selectively handling outbound packet types using transmission techniques suited to each type, DMAC reduces the overhead and complexity of coordinating channel access. DMAC strives to be portable and versatile while using distributed scheduling and traffic control to protect the network against hidden nodes. These techniques provide resilient collision avoidance with nodes beyond carrier sensing range. This allows DMAC to provide an adaptable solution for MAC access in a MANET. We compare DMAC performance to Carrier Sensing Multiple Access with Collision Avoidance (CSMA/CA) in relevant tactic¹al scenarios. The scenarios model a realistic military field deployment with emphasis on the importance of multiple hop communications within a small network. In these scenarios, DMAC provides higher system throughput than CSMA/CA, by avoiding collisions and minimizing scheduling overhead. This provides compelling evidence for DMAC´s potential efficiency gains in MANET environments.