Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
HSDPA/HSUPA for UMTS: High Speed Radio Access for Mobile Communications
HSDPA/HSUPA for UMTS: High Speed Radio Access for Mobile Communications
Computationally efficient bandwidth allocation and power control for OFDMA
IEEE Transactions on Wireless Communications
Downlink Radio Resource Allocation for Multi-Cell OFDMA System
IEEE Transactions on Wireless Communications
A Resource Allocator for the Uplink of Multi-Cell OFDMA Systems
IEEE Transactions on Wireless Communications
Multicarrier modulation for data transmission: an idea whose time has come
IEEE Communications Magazine
Evolving 3G mobile systems: broadband and broadcast services in WCDMA
IEEE Communications Magazine
Evolution map from TD-SCDMA to FuTURE B3G TDD
IEEE Communications Magazine
Multiuser OFDM with adaptive subcarrier, bit, and power allocation
IEEE Journal on Selected Areas in Communications
Transmit power adaptation for multiuser OFDM systems
IEEE Journal on Selected Areas in Communications
A future radio-access framework
IEEE Journal on Selected Areas in Communications
Optimum Channel Allocation in OFDMA Multi-cell Systems
Network Control and Optimization
Energy efficient spatial TDMA scheduling in wireless networks
Computers and Operations Research
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Orthogonal frequency division multiple-access (OFDMA) manages to efficiently exploit the inherent multi-user diversity of a cellular system by performing dynamic resource allocation. Radio resource allocation is the technique that assigns to each user in the system a subset of the available radio resources (mainly power and bandwidth) according to a certain optimality criterion on the basis of the experienced link quality. In this paper we address the problem of resource allocation in the downlink of a multi-cellular OFDMA system. The allocation problem is formulated with the goal of minimizing the transmitted power subject to individual rate constraint for each user. Exact and heuristic algorithms are proposed for the both the single-cell and the multi-cell scenario. In particular, we show that in the single-cell scenario the allocation problem can be efficiently solved following a network flow approach. In the multi-cell scenario we assume that all cells use the same frequencies and therefore the allocation problem is complicated by the presence of strong multiple access interference. We prove that the problem is strongly NP-hard, and we present an exact approach based on an MILP formulation. We also propose two heuristic algorithms designed to be simple and fast. All algorithms are tested and evaluated through an experimental campaign on simulated instances. Experimental results show that, although suboptimal, a Lagrangian-based heuristic consisting in solving a series of minimum network cost flow problems is attractive for practical implementation, both for the quality of the solutions and for the small computational times.