Efficient Margin Adaptive Scheduling for MIMO-OFDMA Systems

• Published in: IEEE transactions on wireless communications Vol. 12; no. 1; pp. 278 - 287
• Main Authors: Moretti, M., Perez-Neira, A. I.
• Format: Journal Article Publication
• Language: English
• Published: New York, NY IEEE 01.01.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptive systems; Algorithm design and analysis; Allocation problems; Allocations; Applied sciences; Channel allocation; Channel Assignment; Channel quality; Channels; Complexity; Complexity theory; Comunicacions mòbils; Comunicacions òptiques; Enginyeria de la telecomunicació; Exact sciences and technology; Frequency division multiple access; Heuristic strategy; Information, signal and communications theory; Interference; Joint optimization; Linear programming formulation; Margin adaptive; MIMO; MIMO systems; MIMO-OFDMA; Mobile telecommunication systems; Multi carrier systems; Multiple access interference; Multiple-input-multiple-output systems; Multiplexing; Multiuser diversity; Numerical results; OFDMA; Optimal resource allocation; Optimization; Orthogonal frequency division multiple access; Performance loss; power allocation; Power allocations; Radiocomunicació i exploració electromagnètica; Resource allocation; Resource management; Scheduling; Signal and communications theory; Spatial dimension; Spatial filters; Strategy; Studies; Sub-carriers; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Vectors; Wireless communication systems; Xarxes locals sense fil Wi-Fi; Àrees temàtiques de la UPC; Performance evaluation; MIMO system; Multiple access; Resource allocation; Frequency division multiple access; Downlink; Linear programming; Numerical method; Scheduling; Subcarrier; Power allocation; Computational complexity; Optimization; Signal interference; Optimal allocation; Heuristic method; Channel allocation; Orthogonal frequency division multiplexing; Problem solving; Spatial filters; Numerical simulation; MIMO; OFDMA
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2012.120412.120355

In this paper we address the problem of margin adaptive scheduling in the downlink of an orthogonal frequency division multiple access (OFDMA) multiple-input multiple-output (MIMO) system. Optimal resource allocation in MIMO systems requires the joint optimization of: a) linear transmit and receive spatial filters, b) channel assignment and c) power allocation. This problem is not convex and its complexity becomes thus intractable already for small sets of users and subcarriers. To reduce the complexity of the problem at hand, we propose a novel heuristic strategy that partitions the users in different groups according to their average channel quality and addresses the original problem by solving a succession of lower-complexity allocation problems. The spatial dimension is employed to prevent multiple access interference from hindering the performance of the sequential allocation. To further reduce the complexity burden we introduce a linear programming formulation in combination with a waterfilling-based strategy to allocate channels and power to the groups of users. Numerical results and evaluation of the computational complexity show that, though suboptimal, in most cases the proposed algorithm manages to exploit in an original way the inherent multi-user diversity of multi-carrier systems to ease the task of resource allocation with a very limited performance loss from the theoretic optimum.