The cognitive radio has been considered as a promising paradigm to achieve efficient spectrum usage by allowing the coexistence of the primary and cognitive radio networks. One fundamental challenge is to ensure the quality of service (QoS) of the primary link while maximizing the achievable transmission rate of the cognitive radio user. In this paper, we investigate the cooperation based spect...

An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio Frequency Interference (RFI), which would cause loss of operation particularly for passive users ...

Increasing demands for high speed wireless access gave rise to new approach to radio communications and spectrum management – Cognitive Radio (CR). One of the key components of cognitive radio – dynamic spectrum access – shows a way to overcome the scarcity of one of the natural resources – radio frequency spectrum. The research in the domain of CR spans the wide area from information and signa...

Cognitive radio is considered as one of the main enablers for provisioning dynamic and flexible spectrum/channel allocation in wireless communications. The reliable data transmission over cognitive radio should employ modulation, coding etc. and thus the performance of such a new communication system should be realized. In this paper, we provide the performance analysis of adaptive modulation o...

The detection reliability of a cognitive radio network improves by employing a cooperative spectrum sensing scheme. However, increasing the number of cognitive radios entails a growth in the cooperation overhead of the system. Such an overhead leads to a throughput degradation of the cognitive radio network. Since current cognitive radio networks consist of low-power radios, the energy consumpt...

Cognitive radio is based on Software Defined Radio (SDR) technology. The commercial success of smart radio applications and cognitive radio networks will be very dependent on cost, performance, and power consumption of SDR hardware platforms. SDR hardware is now available, but many issues have yet to be studied. In this chapter, the authors detail the constraints imposed by recent radio protoco...

TAO JIANG, Ph.D. THESIS, COMMUNICATIONS RESEARCH GROUP, UNIVERSITY OF YORK 2011 Abstract This thesis investigates how distributed reinforcement learning-based resource assignment algorithms can be used to improve the performance of a cognitive radio system. Decision making in most wireless systems today, including most cognitive radio systems in development, depends purely on instantaneous meas...

—The power allocation in an underlay cognitive radio network rises up several challenges due to rapid utilization of the available spectrum hole. In this paper, we propose a noncooperative power-game algorithm to solve the power allocation problem in an underlay cognitive radio network with two main objectives: (i) to provide good quality of service to cognitive radio nodes, and (ii) to protec...

Cognitive Radios have been receiving increasing attention in academia, industry, and government. This has come after several studies indicating that up to 90% of the allocated radio spectrum less than 3GHz is idle most of the time [1]. As a result, spectrum regulation around the world is in progress to allow unlicensed access on a non-interfering [2] [3]. Current researches are investigating di...

Cognitive radio network and vehicular ad hoc network (VANET) are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is empl...