Medium Access Control Protocol for Spectrum Sharing in Cognitive Radio Communication System

Abstract

The frequency allocation performed by regulatory bodies have allocated spectrum for various services through static/fixed spectrum allocation scheme in order to avoid interference among the users, which reveals that most of the frequency bands have already been assigned. However, the regulatory bodies of various countries have found that most of the allocated spectrum is not utilized efficiently at a particular time and location. Therefore, the spectrum is not scarce but the allocated spectrum is underutilized due to the fixed spectrum allocation scheme. Now as the complexities of wireless technology increases, new multidisciplinary approaches for the spectrum sharing/management are required with inputs from technology, economics and regulatory authorities. Recently, the cognitive radio has come into action to handle the spectrum scarcity problem and enhanced the spectral efficiency. This device is based on the dynamic spectrum access (DSA) and opportunistic spectrum access (OSA) schemes for spectrum access/allocation instead of fixed spectrum allocation. These spectrum allocation schemes are the flexible method of assigning spectrum to the cognitive users which defines a set of techniques and models to support the dynamic management of the spectrum and have broader impacts over the society by enabling further growth in the wireless applications and services.