Alleviating self-interference in MANETs

The interference range in multi-hop ad hoc networks (MANETs) is typically twice as large as the transmission range. This phenomenon causes packets of a multi-hop flow to interfere with each other as they are relayed over the multi-hop route. This interference, an instance of the notorious hidden terminal problem, is caused by simultaneous transmissions by down-stream nodes unaware of ongoing transmissions by up-stream nodes. DMAC (deferrable MAC) is a novel MAC protocol that alleviates the hidden terminal problem by deferring further transmissions until the previously transmitted packets travel far enough to avoid interference with the newly transmitted packets. For simple chain topologies, DMAC improves the throughput of CBR and TCP flows by up to 100% and 60%, respectively. For random mobile topologies with up to 40 simultaneous flows, DMAC improves the throughput of TCP flows by up to 30%.