Throughput analysis of double sense multiple access for wireless ad hoc networks

In wireless ad hoc networks, it is a challenging problem to design an efficient random access protocol that can completely avoid interference from hidden terminals, which are defined as terminals out of the radio coverage area of the transmitter but within that of the receiver. The dual busy tone multiple access (DBTMA) protocol, proposed by Z.J. Haas and J. Deng (see IEEE Trans. Commun., vol.50, p.975-85, 2002), uses two out-of-band busy tone (BT) signals to clear other packet transmissions within the radio coverage area of the intended transmitter-receiver pair. As an extension of DBTMA, we propose the double sense multiple access (DSMA) protocol for solving the hidden-terminal problem in wireless ad hoc networks. DSMA uses the "double sense" mechanism and two time-slotted channels, i.e. control and data, to completely avoid data packet collisions. Compared with DBTMA, our DSMA protocol reduces the transmission delay and is more efficient in channel utilization and power consumption. For a realistic non-fully-connected network scenario, the throughput performance of DSMA is derived mathematically and verified by simulation results. The tradeoff relationship between throughput and other parameters is also discussed.