Convex Optimization
Resource allocation for non-real-time services in OFDM-based cognitive radio systems
IEEE Communications Letters
Resource allocation in an OFDM-based cognitive radio system
IEEE Transactions on Communications
Cognitive radio game for secondary spectrum access problem
IEEE Transactions on Wireless Communications
Efficient resource allocation algorithm for cognitive OFDM systems
IEEE Communications Letters
Queue-aware resource allocation for downlink OFDMA cognitive radio networks
IEEE Transactions on Wireless Communications
Radio Resource Allocation Algorithms for the Downlink of Multiuser OFDM Communication Systems
IEEE Communications Surveys & Tutorials
Adaptive resource allocation in multiuser OFDM systems with proportional rate constraints
IEEE Transactions on Wireless Communications
Resource Allocation for Multicast Services in Multicarrier Wireless Communications
IEEE Transactions on Wireless Communications
Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems
IEEE Transactions on Wireless Communications
Optimal and Suboptimal Power Allocation Schemes for OFDM-based Cognitive Radio Systems
IEEE Transactions on Wireless Communications - Part 2
Spectrum pooling: an innovative strategy for the enhancement of spectrum efficiency
IEEE Communications Magazine
Resource allocation for multiuser cognitive OFDM networks with proportional rate constraints
International Journal of Communication Systems
Multiuser OFDM with adaptive subcarrier, bit, and power allocation
IEEE Journal on Selected Areas in Communications
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In this paper, we study the resource allocation problem in multiuser Orthogonal Frequency Division Multiplexing (OFDM)-based cognitive radio networks. The interference introduced to Primary Users (PUs) is fully considered, as well as a set of proportional rate constraints to ensure fairness among Secondary Users (SUs). Since it is extremely computationally complex to obtain the optimal solution because of integer constraints, we adopt a two-step method to address the formulated problem. Firstly, a heuristic subchannel assignment is developed based on the normalized capacity of each OFDM subchannel by jointly considering channel gain and the interference to PUs, which approaches a rough proportional fairness and removes the intractable integer constraints. Secondly, for a given subchannel assignment, we derive a fast optimal power distribution algorithm that has a complexity of O(L 2 N) by exploiting the problem's structure, which is much lower than standard convex optimization techniques that generally have a complexity of O((N + K)3), where N, L and K are the number of subchannels, PUs and SUs, respectively. We also develop a simple power distribution algorithm with complexity of only O(L + N), while achieving above 90 % sum capacity of the upper bound. Experiments show that our proposed algorithms work quite well in practical wireless scenarios. A significant capacity gain is obtained and the proportional fairness is satisfied perfectly.