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A simple quantization-based multibit cooperative spectrum sensing for cognitive radio networks

Cooperative spectrum sensing exploit multiuser diversity to overcome channel fading, shadowing and hidden terminal problem, which can effectively enhance the sensing performance and protect licensed users from harmful interference. In this paper, we address the soft decision fusion strategy in a limited bandwidth of the control channel, and propose a simple quantization-based multibit cooperative sensing method. In the proposed quantization scheme, each cooperative secondary user (SU) adopts energy detector as its simple structure and easily implementation for local spectrum sensing. Each SU transmits multibit quantized data instead of transmitting one bit or the complete observed test statistics to report local sensing results to the fusion center (FC). Furthermore, the closed form expressions of quantization levels and quantization interval are analytically derived. Simulation results demonstrate that, as the number of quantization bit increases, the sensing performance of proposed scheme approaches to that of soft fusion scheme with less overhead. Extensive simulations show that multibit quantization fusion achieves a tradeoff between the sensing performance and the control channel overhead for cooperative spectrum sensing.