Hindawi Publishing Corporation Mathematical Problems in Engineering Volume 2013, Article ID 567581, 14 pages http://dx.doi.org/10.1155/2013/567581 Research Article Reliable, Efficient, and Power Optimized Control-Channel Selection Scheme for Cognitive Radio Networks Saleem Aslam, Adnan Shahid, and Kyung Geun Lee Department of Information and Communication Engineering, Sejong University, Seoul 143-747, Republic of Korea Correspondence should be addressed to Kyung Geun Lee; kglee@sejong.ac.kr Received 12 July 2013; Revised 18 October 2013; Accepted 24 October 2013 Academic Editor: Xi-Ming Sun Copyright © 2013 Saleem Aslam et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis paper presents a centralized control-channel selection scheme for cognitive radio networks (CRNs) by exploiting the variation in the spectrum across capacity, occupancy, and error rate. We address the fundamental challenges in the design of the control- channel for CRNs: (1) random licensed users (LUs) activity and (2) the economical and vulnerability concerns for a dedicated control-channel. We develop a knapsack problem (KP) based reliable, efcient, and power optimized (REPO) control-channel selection scheme with an optimal data rate, bit error rate (BER), and idle time. Moreover, we introduce the concept of the backup channels in the context of control-channel selection, which assists the CRs to quickly move on to the next stable channel in order to cater for the sudden appearance of LUs. Based on the KP and its dynamic programming solution, simulation results show that the proposed scheme is highly adaptable and resilient to random LU activity. Te REPO scheme reduces collisions with the LUs, minimizes the alternate channel selection time, and reduces the bit error rate (BER). Moreover, it reduces the power consumed during channel switching and provides a performance, that is, competitive with those schemes that are using a static control-channel for the management of control trafc in CRNs. 1. Introduction In recent years, most researchers and leading communication agencies have decided to adopt the dynamic spectrum man- agement framework for handling the spectrum requirements of upcoming advanced communication systems. Such a shif in the spectrum management paradigm requires a robust communication radio that can meet the stringent demands of the future generation of communication systems. Cognitive radio (CR), or reconfgurable radio, seems to be the best technology for dynamic spectrum access [1–4]. CRs employ the spectrum-sensing scheme to locate empty spots within the radio spectrum band and then utilize the sofware routines using sofware-defned radio (SDR) for parameter adjustment. Te CR can operate in the vacant portion of the licensed band only if they operate under a tolerable interference limit with LUs [5]. From the perspective of the CR, there are fve main functions spectrum sensing: spectrum analysis, spectrum decision, spectrum sharing, and spectrum mobility [2–5]. As an example, the network control systems (NCS) are heavily investigated to manage the packet drop and latency of control-channel [6, 7]. Various methods for evaluating the stability analysis of the NCS are discussed in [8–10]. However, these schemes are focused for NCS rather than the dynamic communication environment like CRNs. To locate and select the best control-channels in terms of availability time and quality, spectrum sensing, analysis, and decision schemes play a crucial role. Te spectrum sharing scheme helps in the optimal allocation of the available free channel/spectrum among competing CRs, whereas the spectrum mobility helps the CRs to avoid interference with the LUs by switching the CR to the next available channel. From the perspective of the LU networks, a user has the legitimate right to use the spectrum under the contract of the service provider. To have better coordination and synchronization among diferent components, the CRs need to exchange signifcant amount of the control information to make a timely decision about spectrum sensing, sharing, and mobility tasks [11]. Terefore, a stable and better quality control-channel is required to meet the desired efciency. By selecting a better quality control-channel, the CRNs can provide a better communication environment to its users and