Publication

Abstract : With the fast-growing wireless communication and limited spectrum availability, cognitive radio is emerging as promising solution to support ever increasing demand for applications and services. In weak signal conditions, spectrum sensing by unlicensed users gets severely affected by shadowing and fading conditions. In such conditions, channel state estimation of the primary channel would be useful. However, this would lead to significant transmission overheads. In this paper, an innovative fuzzy-based spectrum sensing technique to overcome the drawbacks in conventional cooperative spectrum sensing is proposed. The fuzzy-based cooperative spectrum sensing technique presented in this paper considers sensing results of three secondary nodes; i.e., the node under consideration along with two neighboring nodes, to decide upon the sensing result from any node, which makes this technique very robust and efficient in noisy conditions. Diversity combining techniques are implemented to calculate the signal energy values for consideration at the fuzzy center. These energy values are considered, and final decision on the sensing energy is evaluated by a novel rule-based algorithm, which resulted in improved sensing accuracy for finding the presence of primary user. Further, the proposed algorithm uses multiple threshold values to determine the primary user presence to tackle low signal-to-noise ratio conditions. Results obtained prove that the proposed method in this work outperforms the existing schemes and is able to achieve accurate sensing results and gives better results than conventional schemes in noisy conditions.