On the Construction of Radio Environment Map for Cognitive Radio Applications: An Overview

Abstract: Demand for data services from a few Kilobytes to several Gigabytes over the last 25 years has led to the development of several mobile and wireless standards. Unfortunately, the spectrum required for these services to operate is becoming scarce not because of shortage but because of under-utilization as several spectrum occupancy measurements have shown over the years. The solution then has to be a dynamic spectrum access approach where licensed and unlicensed users could share the spectrum without causing interference to the licensed user. This concept known as Cognitive Radio (CR) was envisioned by Mitola promises to solve this problem. Radio Environment Map (REM) is one of the central tools at the heart of CR as it constructs a comprehensive map of the CR network storing information on physical network, policies, regulation, licensed user profile and activity. In this research, a general overview on REM construction is presented. From the architecture to the techniques applied in constructing REMs. The performance of propagation models employed in this process is also presented. Finally the quality metrics used to determine the accuracy of the constructed REMs is given

Keywords: Cognitive radio, Radio environment map, propagation models, quality metrics