Distributed Approach for Power and Rate Allocation to Secondary Users in Cognitive Radio Networks
ABSTRACT We consider a multichannel cognitive radio network where multiple secondary users (SUs) share a single channel and where multiple channels are simultaneously used by a single SU to satisfy their rate requirements. We attempt to evaluate the optimal power and rate distribution choices that each SU has to make to maintain their quality of service (QoS). Our measures for QoS include bit error rate (BER) and minimum rate requirement. We design a QoS-constrained bi-objective optimization problem with the objective of minimizing transmit power and maximizing rate. Unlike prior efforts, we transform the BER constraint into a convex constraint to guarantee optimality of the resulting solution. Our interest in this paper is to develop a user-based distributed approach to solve the optimization problem and compare the solution with the centralized approach. We employ dual decomposition theory to derive three different formulations of the distributed problem. Simulation results demonstrate that optimal transmit power follows the “reverse water filling” process and that rate allocation follows signal-to-interference-plus-noise ratio (SINR). We show that the solutions from the distributed formulations follow the centralized solution.
Conference Paper: A survey on security in Cognitive Radio networks[Show abstract] [Hide abstract]
ABSTRACT: Cognitive radio (CR) has been introduced to accommodate the steady increment in the spectrum demand. In CR networks, unlicensed users, which are referred to as secondary users (SUs), are allowed to dynamically access the frequency bands when licensed users which are referred to as primary users (PUs) are inactive. One important technical area that has received little attention to date in the cognitive radio system is wireless security. New classes of security threats and challenges have been introduced in the cognitive radio systems, and providing strong security may prove to be the most difficult aspect of making cognitive radio a long-term commercially-viable concept. This paper addresses the main challenges, security attacks and their mitigation techniques in cognitive radio networks. The attacks showed are organized based on the protocol layer that an attack is operating on.2014 6th International Conference on Computer Science and Information Technology (CSIT); 03/2014
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ABSTRACT: In multi-channel cognitive radio networks, each secondary user can use multiple channels for data transmission to improve the spectrum utilization. In this paper, we investigate the resource allocation problem for multi-layered video streaming over multi-channel cognitive radio networks. The video is encoded into multiple layers, each of which is delivered over a separate channel. Moreover, we jointly optimize the source rate, the transmission rate, and the transmission power at each video session in each channel to provide Quality of Service (QoS) guarantee to all video sessions in the secondary network. The optimization problem is formulated into a Geometric Programming (GP) problem, which can be solved efficiently. We demonstrate in the simulations that the proposed optimal scheme can obtain a lower average Packet Loss Rate (PLR), thus leading to a higher video quality compared to the equal scheme.Trust, Security and Privacy in Computing and Communications (TrustCom), 2012 IEEE 11th International Conference on; 01/2012
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ABSTRACT: In this paper, the resource allocation for OFDMA-based cognitive radio (CR) system is considered. We propose a two-step resource allocation algorithm that maximizes the sum throughput of the system while satisfying the quality of service (QoS) requirements for guaranteed users (GUs). By the first step, the sum power of the guaranteed users is minimized as the guaranteed rate is provided. By the second step, the remaining resources are distributed among all users so that the sum throughput is maximized. In both steps, power allocation is performed in a way that the adverse interference on the primary users (PUs) is avoided. Simulation results show that the proposed algorithm is highly efficient in terms of rate guarantee for GUs and sum throughput maximization.Telecommunications (IST), 2012 Sixth International Symposium on; 01/2012