Performance Enhancement of Multi-antenna Correlated Receiver for Vehicular Communication using Modified Threshold Approach

In Cognitive Radio (CR), accurately detecting Primary User (PU) signal through spectrum sensing techniques is the foremost requirement. For Energy Detection method, selection of appropriate threshold is expected to improve efficiency of CR. This paper presents modified threshold approach that estimates the threshold parameters by incorporating the effect of Noise Uncertainty (NU). Authors have considered L correlated branches of multiple antenna receiver under the effect of mobility for spectrum sensing through Energy Detector (ED). The performance analysis is carried over Nakagami-m fading channel with constant, exponential and arbitrary correlation between the elements of antenna. The approach of Moment Generating Function (MGF) is considered to conveniently obtain statistical values of Signal to Noise Ratio (SNR). Further, lauricella and confluent hypergeometric functions are used for obtaining closed form of expression of Probability of Detection for Maximal Ratio Combining (MRC) diversity technique. It is observed that the performance of source algorithm is significantly improved using the modified threshold parameter over entire range of SNR. The further improvement for detection performance is observed with increase in number of branches in antenna. Moreover, at high value of fading parameter (m=4) for MRC diversity, the detection probability with exponential correlation between L elements is found superior compared to constant and arbitrarily correlated branches.