Guest Editorial
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| Title | Guest Editorial |
| Authors | |
| Abstract | Recent advances in cognitive radio technology have enabled wireless devices and networks to efficiently locate and exploit under-utilized spectrum. This has motivated the re-evaluation of spectrum management policies worldwide since the current command-and-control management model has created an “artificial” scarcity of spectrum by assigning fixed property rights to various spectrum bands. The new technology and policy changes pose many new technical challenges in various aspects of wireless communication and networking, such as interference management, distributed algorithm design, QoS guarantees, mobility management, and network interoperability.The goal of this Special Issue is to bring together the state-of-art research contributions that address the major opportunities and challenges of cognitive radio communications and networking. We received a total of 12 papers in response to our Call for Papers, and accepted 6 ones after a careful review process. Papers were selected based on their appropriateness for and relevance to the Special Issue as well as their technical merits. We want to thank all the authors who submitted their work to this Special Issue. We also want to thank all the reviewers who provided detailed and insightful reviews and comments, within the tight deadlines given to them. The 6 accepted papers cover a widely range of interesting topics related to cognitive radio technology as follows.Alshamrani, Shen and Xie, in “A Cooperative MAC with Efficient Spectrum Sensing Algorithm for Distributed Opportunistic Spectrum Networks,” propose an efficient medium access control (MAC) framework that integrates cooperative spectrum sensing method at the physical layer into a cooperative MAC protocol. Moreover, a computationally simple but efficient sensing algorithm is developed to assist each sensing user to identify the optimal number of channels to sense and the optimal sensing duration. Sula and Zhou, in “A Cooperative Scheme for Spectrum Sensing in Cognitive Radio Systems,” develop a cooperative spectrum-sensing scheme from a comprehensive perspective including sensing, communication, decision, and transmission. Simulation results indicate that the new scheme provides an adequate answer to some of the most challenging aspects of cognitive spectrum sensing. Jiao and Li, in “A Dynamic Parallel-rendezvous MAC Mechanism in Multi-rate Cognitive Radio Networks: Mechanism Design and Performance Evaluation,” propose a new MAC scheme where secondary users jump among different channels according to their own distinct hopping sequences and a node can adjust its hopping sequence according to channel conditions in order to achieve higher system capacity. Numerical results show that the new mechanism can significantly improve system capacity of cognitive radio networks compared with the traditional channel hopping MAC mechanisms. Like, Temple and Wu, in “SMSE Waveform Design Using Soft Decision Selection and Dynamic Assignment of Subcarrier Modulation Order and Power,” provide the analytical development for optimizing Spectrally Modulated Spectrally Encoded (SMSE) waveform performance in a coexistent environment containing Primary User (PU) signals. Relative to a spectrally only adapted waveform, the spectrally-temporally adapted SMSE waveform provides significant performance improvement. Maximum improvement is achieved using statistic-based prediction of PU channel temporal conditions and the appropriate SMSE waveform design update interval. Akter and Natarajan, in “A Two-Stage Power and Rate Allocation Strategy for Secondary Users in Cognitive Radio Networks,” evaluate the optimal power and rate distribution choices for secondary users in order to maintain their QoS in a multi-channel cognitive radio network. They propose a two-stage optimization framework in order to solve for the optimal resource management strategy.The invited (overview) paper is from Huang and Krishnamurthy. The authors present several results in game theory and their applications in cognitive radio systems. First, they compute the Nash equilibrium power allocation and rate adaptation policies in cognitive radio systems using static game and dynamic Markovian game frameworks. They then describe how mechanism design helps to design a truth revealing channel access scheme. Finally, they introduce the correlated equilibrium concept in stochastic games and its application to solve the transmission control problem in a cognitive radio system. We hope that you will enjoy reading this Special Issue devoted to the exciting fast-evolving field of Cognitive Radio Communications and Networking as much as we have. |
| Publisher | ACADEMY PUBLISHER |
| Date | 2009-11-01 |
| Source | Journal of Communications Vol 4, No 10 (2009): Special Issue: Cognitive Radio Enabled Communication and Networking |
| Rights | Copyright © ACADEMY PUBLISHER - All Rights Reserved.To request permission, please check out URL: http://www.academypublisher.com/copyrightpermission.html. |