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Reduced feedback and random beamforming for OFDM MIMO broadcast channels

Fakhereddin, Maralle J. and Sharif, Masoud and Hassibi, Babak (2009) Reduced feedback and random beamforming for OFDM MIMO broadcast channels. IEEE Transactions on Communications, 57 (12). pp. 3827-3835. ISSN 0090-6778.

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It has been shown that random beamforming using partial channel state information (CSI) achieves the same throughput scaling as obtained from dirty paper coding for a broadcast (downlink) channel with M transmit antennas and K users where K is large. In this paper, we apply this scheme to wideband MIMO broadcast channels. By using OFDM, an L-tap wideband channel can be decomposed to N parallel narrowband channels (subcarriers), where N > L. Neighboring subcarriers are highly correlated. Therefore, we consider neighboring subcarriers as a cluster and find the closed form solution for the joint characteristic function of SINR values at two subcarriers in a cluster. We show numerically how the knowledge of the quality of the center subcarrier sheds light about the quality of other subcarriers in the same cluster, and address the issue of cluster size. In addition, through complex and asymptotic analysis, we show that for cluster size of order N/L√(log K) (for large K), users need only feedback the best SINR at the center subcarrier of each cluster in order for the transmitter to perform opportunistic beamforming and maintain the same throughput scaling as when full CSI is available. Using simulation results, we verify our analytical result and show that even fewer feedback can be tolerated, and larger clusters (N/2L) can be implemented for a small throughput hit.

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Additional Information:© 2009 IEEE. Paper approved by S. N. Batalama, the Editor for Spread Spectrum and Estimation of the IEEE Communications Society. Manuscript received July 17, 2006; revised June 15, 2007, January 19, 2008, and June 5, 2008. This work was supported in part by the National Science Foundation under grant no. CCR-0133818, by the office of Naval Research under grant no. N00014-02-1-0578, and by Caltech’s Lee Center for Advanced Networking. A conference version of this paper was presented at SPAWC, June 2005.
Funding AgencyGrant Number
Naval ResearchN00014-02-1-0578
Caltech's Lee Center for Advanced NetworkingUNSPECIFIED
Subject Keywords:Channel state information; OFDM; broadcast channel; random beamforming; multi-user diversity; wireless communications
Issue or Number:12
Record Number:CaltechAUTHORS:20100126-100241646
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Official Citation:Fakhereddin, M.; Sharif, M.; Hassibi, B., "Reduced feedback and random beamforming for OFDM MIMO broadcast channels," Communications, IEEE Transactions on , vol.57, no.12, pp.3827-3835, December 2009 URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17306
Deposited By: Tony Diaz
Deposited On:29 Jan 2010 16:57
Last Modified:03 Oct 2019 01:25

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