Multiple Beacon Based Robust Cooperative Spectrum Sensing in MIMO Cognitive Radio Networks

This paper introduces novel detection schemes for multiple beacon signaling based cooperative spectrum sensing in multiple-input multiple-output (MIMO) wireless cognitive radio (CR) networks with channel state information (CSI) uncertainty. We consider a scenario in which the fusion center employs soft combining of the samples sensed by the cooperating secondary users corresponding to the primary user base-station beacon signals. We formulate the multiple beacon signaling based robust detectors, namely the robust estimator-correlator detector (RECD) and the robust generalized likelihood detector (RGLD), that can be employed at the fusion center towards primary user detection incorporating CSI uncertainty for cooperative spectrum sensing in MIMO CR networks. Further, we formulate a deflection coefficient based optimization framework and derive the optimal beacon sequence to maximize the probability of primary user detection at the fusion center. Simulation results show that the proposed robust detectors yield a significant improvement in the detection performance compared to the conventional CSI uncertainty agnostic matched filter (MF) detector for cooperative spectrum sensing in MIMO CR networks. Moreover, the optimal beacon signaling based robust detectors result in additional enhancement in the accuracy of primary user detection over suboptimal beacon structure based detectors.