Abstract
This paper presents a new low delay centralized cooperative spectrum sensing method based on dynamic voting rule using multiple threshold level, for indoor hospital environment, where fading and direct path loss both are together responsible for variation in signal strength. In the proposed algorithm, weights of Cognitive Radios (CRs) in terms of assigned vote-count are estimated based on the sensed energy values with respect to multiple fixed threshold levels, so that the direct path loss can be dealt without further increasing the error, which occurs due to fading. For indoor hospital like environment, Rician fading model is more appropriate. Therefore, formulation, evaluation and analysis of various sensing performance parameters have been carried out considering Rician fading model. Comparative analysis and trade-off among three optimum parameters-energy threshold, total number of CRs participating in sensing and total error rate, are presented with respect to signal to noise ratio (SNR). Finally, the Monte Carlo simulation is designed and implemented considering the two conditions-only fading environment and fading along with direct path loss environment. It can be observed that in both cases, the proposed spectrum sensing rule outperforms the other contemporary rules.