Centralized Opportunistic Scheduling Technique Based on Leach for Tv White Space Spectrum

Abstract

This research thesis aims at improving the efficient use of the unlicensed spectrum freed by Analogue to Digital TV transmission transition referred to as Television White Space (TVWS). TVWS networks have a wide scope of applications. One of the recent growing applications is in the domain of Internet of Things (IoT), which permits inter-communication of different things or gadgets through the Internet. Wireless networks in TVWS face challenges such as short network lifetime, untimely energy exhaustion and interference with primary users and hence the need to optimize their operations. In this research work, a centralized opportunistic scheduling technique (COST) based on Low Energy Clustering Hierarchy (LEACH), with cognitive nodes capable of sensing primary users is used to provide a solution to these challenges. A MatLab r2014b based simulation package has been designed to simulate the technique for the TVWS spectrum in a Wireless Sensor Network (WSN). A low consumption energy protocol for WSNs based on remaining energy of cognitive nodes and primary user’s energy detection by cognitive nodes is adapted for TVWS networks. Energy detection allows the cognitive nodes/secondary users to co-exist with primary users with minimum interference. Transmission paths are determined according to the position of cognitive nodes and their cluster heads. By comparing the actual distance of the cognitive node to White Space Base Station (WBS) and the pre-set threshold distance, a decision is made whether to use direct communication from cognitive node network cluster head to White Space Base station or through white space Modem here after referred as Modem (MD). The comparison of the proposed protocol with LEACH and LEACH-C is done in MatLab. Performance analysis of the metrics namely throughput, network lifetime and energy consumption show that the COST-LEACH protocol outperforms both.