FPGA implementation of cooperative spectrum sensing for Cognitive Radio networks

Spectrum sensing is a critical and major component in Cognitive Radio (CR). Due to low signal to noise ratio (SNR), fading and shadowing effects a single CR node is not reliable for accurate detection. This motivates the study of cooperative spectrum sensing. In this paper, each CR uses energy detection method based on Neyman-Pearson criteria for local spectrum sensing. The individual decisions of each CR are integrated in the fusion center using different fusion rules. In this paper more specifically first the authors analyses and compares the performance of different fusion rules such as logical AND, OR and Equal Gain Combining (EGC) integrated either soft or hard decision rules. Second, the cooperative sensing technique is implemented in the Xilinx Virtex-2pro XC2VP30 (FFG896-7C) Field Programmable Gate Array (FPGA). Hardware in loop (HIL) simulation technique is used for verification of the algorithm in FPGA. HIL simulation result shows that EGC fusion rule is more appropriate for sensing the considered DVB-T signal upto -16dB SNR with probability of detection (Pd) ≥ 0.9 and probability of false alarm (Pf) ≤0.1. The implementation results reveal that the algorithm works with operating frequency of 149.5 MHz.