Performance analysis of cooperative spectrum sensing for cognitive radio using stochastic geometry

In this paper, we analyse (censored) cooperative spectrum sensing for cognitive radios (CRs) where, in order to save power, each CR only transmits its test statistic to a fusion center (FC) if the test statistic is greater than some threshold (ξ). One problem with this approach is that, it is possible that no test statistics may be transmitted. The solution that we propose here is to choose an optimum test statistic threshold (ξ = ξ_opt) to avoid (probabilistically) no test statistic being transmitted to the FC. We also propose the additional power saving approach where only if the required CR transmit power (P_i, to achieve a required SNR at the FC) is less than some optimum transmit threshold (P_t = P_topt) do we transmit the test statistic. We then show the effect of (ξ_opt, P_topt) on both the detection performance at the FC (using selection combining) and the total CRs transmit power. Finally, simulation results show this approach mitigates the original problem (in an energy efficient way) of no CR test statistic being transmitted to the FC.