Mitigation of Exposed Terminal Problem Using Packet Sensing

Spatial reuse is critical for ad hoc network with limited bandwidth. Exposed terminals are refrained from transmitting in 802.11 like protocols and the network capacity is wasted in high-density ad hoc network. In this paper, we propose a new scheme named SB-FSMA/CA to mitigate the exposed terminals problem in static ad hoc network or mesh network. SB-FSMA/CA mitigates exposed terminals problem by using signal strength of the neighboring nodes. 2-hop neighbor´s information and dialogue correlation coefficient are two key features of our proposed scheme. Based on the 2-hop neighbor´s information, an exposed terminal captures a frame of ongoing dialogue and calculates the correlation coefficient between the primary dialogue and dialogue to be built before trying to transmit. If the correlation coefficient is lower than a certain threshold, the exposed terminal is permitted to communicate with its destination in parallel with primary dialogue. SB-FSMA/CA mitigates exposed terminals problem by allowing exposed terminals satisfying the correlation coefficient constraint to transmit simultaneously. Simulation result shows that the average throughput of SB-FSMA/CA outperforms that of 802.11 DCF by 25% in high-density ad hoc network.