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Performance analysis of layered random beamforming OFMDA with feedback reduction

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Original languageEnglish
Title of host publicationIEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2007), Athens
Publisher or commissioning bodyInstitute of Electrical and Electronics Engineers (IEEE)
Pages1 - 5
Number of pages5
ISBN (Print)9781424411443
StatePublished - 3 Sep 2007
Event18th International Symposium on Personal, Indoor and Mobile Radio Communications (2007) - Athens, Greece


Conference18th International Symposium on Personal, Indoor and Mobile Radio Communications (2007)
Abbreviated titlePIMRC
Period1/09/07 → …


This paper presents a downlink performance analysis of a Layered Random Beamforming (LRB) - MIMO-OFDMA Physical Layer (PHY) with feedback reduction as applicable to future generation wireless communication systems. OFDMA is a popular multiple access candidate for future generation cellular communication systems which facilitates multi-user diversity by enabling multiple access in the frequency domain. LRB enables the exploitation of spatial multi-user diversity gain, spatial multiplexing capacity gain and layer spatial multi-user diversity gain, which is achieved by enabling the multiplex of data transmitted simultaneously to different destinations. Unlike a conventional beamforming system, an LRB system only requires effective signal to interference and noise ratios (ESINR) as feedback from every spatial layer of the MIMO channels and thus has potentially lower feedback requirements than a system which requires feedback of more detailed channel information. By combining the LRB technique with OFDMA, LRB-OFDMA can achieve an additional spectral multi-user diversity gain compared to the single carrier LRB system. However, in this case ESINR feedback on a per-sub-carrier basis is required in principle and the feedback requirements may thus increase substantially. This feedback requirement can be reduced by generating the feedback information on a cluster (group of sub-carriers) basis rather than on an individual sub-carrier basis. In this way, the system can exploit any correlation in the frequency response of the channel. The design of an LRB-OFDMA system is presented in this paper and the performance of the system is evaluated for different degrees of feedback reduction using various statistical channel models.

Additional information

Rose publication type: Conference contribution Additional information: With accompanying conference poster Sponsorship: The authors wish to acknowledge the financial support of Dorothy Hodgkin Postgraduate Awards (DHPA) and Toshiba Research Europe Limited (TREL) and to thank Dr. Magnus Sandell of TREL for his technical input. Terms of use: Copyright © 2007 IEEE. Reprinted from IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007 (PIMRC 2007). This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Bristol's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.

Research areas

  • random beamforming, OFDMA


18th International Symposium on Personal, Indoor and Mobile Radio Communications (2007)

Abbreviated TitlePIMRC
Duration1 Sep 2007 → …

Event: Conference

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