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In this paper, we study spectrum overlay access to share spectrum between primary users (PUs) and secondary users (SUs). Our goal is to maximize the average throughput by optimal power allocation within finite time duration. To do this, we formulate this optimization problem as a Markov Decision Process with continuous state. An approximate value method with pre-allocation mechanism is proposed, which...
In this paper, we investigate the robust power allocation issue in orthogonal frequency division multiplexing-based cognitive radio networks (CRNs) with unavoidable uncertainties (channel perturbations and variable environment). In this case, to control the performance degradation due to the uncertainties, we maximize the data rate of secondary users (SUs) by considering maximum allowable interference...
Spectrum access approach and power allocation scheme are important techniques in cognitive radio (CR) system, which not only affect communication performance of CR user (secondary user, SU) but also play decisive role for protection of primary user (PU). In this study, we propose a power allocation scheme for SU based on the status sensing of PU in a single-input single-output (SISO) CR network. Instead...
This paper investigates power allocation problems for orthogonal frequency division multiplexing (OFDM)-based cognitive radio networks operating in licensed frequency bands. Considering imperfect spectrum sensing, a new power allocation algorithm is proposed to minimize the total interference introduced to primary user under a minimum capacity constraint of secondary user (SU) and a total transmit...
Cognitive radio (CR) is an innovative technique to improve the utilization of radio frequency spectrum, in which different users compete for limited resources. Non-contiguous orthogonal frequency division multiplexing (NC-OFDM) is regarded as a well-matched technology for CR systems. In these systems, one of the major concerns is the fairness of resource allocation among secondary users. In this paper,...
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