An Approach Towards Improving Energy Efficiency in Cognitive Radio Networks

Abstract

Due to the great advancements in the field of wireless communications and connected devices, the need for more spectrum resources reaches a higher extent. As the generations in mobile technology are incremented then and there, the spectrum allocated newly also gets increased. But for Fifth Generation (5G), this allocation is not enough and the available spectrum is noted to be meagre. At the same time, the current fixed spectrum policy has left some portions of the spectrum under-utilized during certain durations and locations. Due to the increased need for spectrum resources, the additional allocation has to be supported by some smart technology to utilize spectrum wisely, where the role of Cognitive Radio (CR) is introduced. CR is observed to be a solution for the problems of spectrum scarcity and under-utilization, which forms the base of this thesis. The core work of this thesis is to develop energy conserving methodologies to bring Energy Eand#64259;ciency (EE) in CR networks. At the same time, Spectrum Eand#64259;ciency (SE) and performance of the network have to be preserved and improved. newlineInitially, this research work concentrates on the importance of fusion methods, which play a significant role in obtaining the Primary User (PU) status in Cooperative Spectrum Sensing (CSS). Diand#64256;erent types of hard and soft fusion methods are studied and their significance are analysed. A weight based improved hard fusion method has been proposed for increasing detection performance in CR networks. Also, a reporting strategy is applied to minimize the number of reporting users with energy conservation. An improved Majority fusion method with varying threshold has been proposed and simulated. Also, a relay assisted cooperative sensing method has been proposed for improving hard fusion, where the low energy users can be assisted with Relay Users (RUs) to conserve energy and improve detection. Then, a pipelined frame structure combining both sensing and reporting