Robust Cooperative Sensing With ON/OFF Signaling Over Imperfect Reporting Channels

In this paper, we propose an on/offreporting mechanism for cooperative sensing of cognitive radio so that reporting overhead from secondary sensing users to a fusion center can be significantly reduced. A key advantage of our scheme is robust and energy-efficient cooperative sensing over imperfect reporting channels. Furthermore, ON/OFF reporting enables graceful degradation when sensing nodes fail during operation. We focus on hard decision of cooperative sensing with many energy detectors based on the Neyman-Pearson criterion. Instead of using the conventional and rule, we propose an iNOR rule that can achieve O(1) reporting overhead in total, irrespective of the number of sensing nodes. The asymptotic overhead value is given by P(H
₁
) log (1/P̅
_d
), where P(H
₁
) is the probability of primary user's presence and P̅
_d
is the target detection probability. In addition, we show that the or rule also has its asymptotically negligible reporting overhead given by P(H
₁
) log (1/1-P
_d
). Significant reduction in reporting overhead of ON/OFF reporting contributes to power saving, which in turn realizes robust reporting to fusion center by overcoming channel fading. Our simulation results show that with the proposed technique fusion center can make a reliable decision to avoid harmful interference to the primary user.