Enhancement of Equal Gain Combiner for Detection of Spectrum Hole in a Cognitive Radio System
Ojo S. I., Zachaeus Kayode Adeyemo, Ojo F. K., Adedeji A. A, Folasade Abiola Semire · Universal Journal of Electrical and Electronic Engineering · 2020
Cognitive Radio System (CRS) is of paramount importance in wireless communication for spectrum management. However, channel impairment affects accurate Spectrum Hole Detection (SHD) in CRS resulting in harmful interference to a licensed user. Conventional Equal Gain Combiner (EGC) which is one of the techniques being used to solve the problem suffers from hardware complexity resulting in high Sensing Time (ST). Hence, in this paper, an Enhanced EGC (EEGC) for SHD in a CRS is proposed to reduce the hardware complexity of conventional EGC. Ten thousand (10,000) bits are randomly generated, modulated using Binary Phase Shift Keying (BPSK) scheme and propagated over Rayleigh fading channel. The received signals through three antennas are scanned by three Selection Combiners (SCs) to select the branch with highest Signal to Noise Ratio (SNR). The outputs of the three SCs are then combined using conventional EGC. The output of conventional EGC is used as input to single Energy Detector (ED) to determine the energy of the combined signal. A mathematical expression for Probability of False Alarm (PFA) for the proposed technique is derived using X2 distribution to set thresholds at 0.01 and 0.02. The proposed technique is simulated using MATLAB software and evaluated using Probability of Detection (PD), ST and Probability of Missing (PM). The results obtained show that EEGC gives better performance with lower ST, higher PD and lower PM.