How to Select the OOK Detection Threshold in Wireless Ad Hoc and Sensor Networks

On-off keying (OOK) is an attractive modulation technique to reduce energy consumption of power-constrained wireless networks. The OOK detection threshold, however, must be carefully selected to minimize the bit error probability (BER). This is a challenging task to accomplish on resource-limited nodes or on networks with high-mobility. In this paper, an efficient algorithm to compute the optimal threshold is proposed. The system scenario considers nodes simultaneously transmitting over same frequencies in Rayleigh-log-normal or Rice-log-normal fading conditions. It is shown that by using the Stirling expansion for the BER, and a log-normal approximation, a quick contraction- mapping can be built to achieve the threshold numerically. The mapping is simple to implement and converges quickly. Numerical simulations verify the validity of the theoretical analysis, and show that the new algorithm performs quite well in scenarios of practical interest.