Tutorial

Emerging technologies in the domain of wireless communication systems have paid more attention towards maximizing resource utilization by supporting increasing number of users with diverse applications day-by-day. However, spectrum congestion is the biggest challenge towards developing a scalable and robust communication system with high Quality of Service (QoS) requirements. Cognitive Radio Network (CRN) is one such promising technology that reduces the constraint of bandwidth limitation by introducing opportunistic usage of the frequency bands that are not heavily occupied by licensed users. Real-world implementation ofCRN, thus, faces unique challenges in the field of spectrum sensing, analysis, management, mobility and sharing, along with proper tuning of wireless device parameters and regulations on spectrum usage. The ultimate goal of any CRN based system is to maximize spectrum utilization by allowing secondary or unlicensed users (SUs) to access available spectrum slots when the primary or licensed users (PUs) are absent. Accordingly, research focus isinclined towards capacity scaling and enhancement in CRN through strategies like spectrum handoff, channel reservation schemes, proper Medium Access Control (MAC) protocols and so on. CR is a paradigm for wireless communication in which either network or wireless node itself changes particular transmission or reception parameters to execute its tasks efficiently. This parameter alteration is based on observations of several factors from external and internal cognitive radio environment, such as radio frequency spectrum, user behavior, and network state. The aim of this lecture is to provide the aspect of Cognitive Radio Networks and some focused research that we are currently doing at Broadband Wireless Communication LAB of ETCE Department, Jadavpur University.