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Open Access

On Throughput-Fairness Tradeoff in Virtual MIMO Systems with Limited Feedback

  • Alexis A. Dowhuszko1Email author,
  • Graciela Corral-Briones1,
  • Jyri Hämäläinen2 and
  • Risto Wichman3
EURASIP Journal on Wireless Communications and Networking20092009:102064

Received: 1 July 2008

Accepted: 24 January 2009

Published: 4 March 2009


We investigate the performance of channel-aware scheduling algorithms designed for the downlink of a wireless communication system. Our study focuses on a two-transmit antenna cellular system, where the base station can only rely on quantized versions of channel state information to carry out scheduling decisions. The motivation is to study the interaction between throughput and fairness of practical spatial multiplexing schemes when implemented using existing physical layer signaling, such as the one that exists in current wideband code division multiple access downlink. Virtual MIMO system selects at each time instant a pair of users that report orthogonal (quantized) channels. Closed-form expressions for the achievable sum-rate of three different channel-aware scheduling rules are presented using an analytical framework that is derived in this work. Our analysis reveals that simple scheduling procedures allow to reap a large fraction (in the order of 80%) of the sum-rate performance that greedy scheduling provides. This overall throughput performance is obtained without affecting considerably the optimal short-term fairness behavior that the end users would perceive.


Channel State InformationCode Division Multiple AccessThroughput PerformanceSchedule RuleLimited Feedback

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Authors’ Affiliations

Digital Communications Research Laboratory, National University of Cordoba (UNC) - CONICET, Cordoba, Argentina
Department of Communications and Networking, Helsinki University of Technology (TKK), Finland
Department of Signal Processing and Acoustics, Helsinki University of Technology (TKK) - Smart and Novel Radios (SMARAD) Centre of Excellence, Finland


© Alexis A. Dowhuszko et al. 2009

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.