Cooperative Spectrum Sensing with Noisy Hard Decision Transmissions

Most critical component of the cognitive radio paradigm is spectrum sensing and accordingly, detection of primary users. Recently proposed cooperative spectrum sensing methods do not consider errors occurring during the transmission of local cognitive radio decisions to the cognitive base station. However, perfect communication is clearly not the case in realistic cooperative spectrum sensing scenarios and might lead to misleading performance result interpretations. In this paper, we extend the simple cooperative spectrum sensing communication model to admit transmission imperfections. Specifically, we consider the case where the local hard cognitive radio decisions that are based on any local detection scheme are corrupted by additive noise during transmission from cognitive radios to cognitive base station. Utilizing this extended cooperative spectrum sensing model, we present the complex optimal and a practical and effective suboptimal detector that is capable of operating with any local cognitive radio detection scheme: Two-step detector. We present simulation results investigating the performance of the proposed detectors and the effect of parameters of interest such as number of cognitive radios and signal to noise ratio. Moreover, we provide comparisons between non-cooperative and cooperative spectrum sensing performances revealing some cases where non-cooperative scheme is more effective.