Proactive channel access scheme for wireless ad hoc networks

In wireless ad hoc networks, the channel access scheme allows different nodes to communicate simultaneously without creating outages at nearby nodes. Therefore, the scheme should be easy to implement, i.e. with as little coordination between the nodes as practically possible and it should be able to schedule the maximum number of concurrent transmissions. The proposed scheduling scheme ensures the spatial separation among packed nodes by suppressing the active interferers around an active receiver. Moreover, the scheme utilises each interferer's transmitter-receiver (Tx-Rx) separation to make a decision regarding its inclusion in the scheduled transmissions. The proposed scheme not only gives significant increase in the transmission capacity as compared with the random ALOHA but also outperforms the latest guard zone-based scheduling scheme for the distributed ad hoc networks. Additionally, it performs nearly as good as the near-optimal centralised scheduling scheme. While the attainable transmission capacity is comparable but still inferior to the centralised scheme, it can be implemented easily in a distributed manner, unlike the centralised scheme. The derived results provide the optimal guard zone size and corresponding transmission capacity under varying network parameters - outage probability, path-loss exponent, maximum Tx-Rx separation, and spread spectrum's spreading gain.