Performance analysis for RUB-based multiuser MIMO systems with antenna diversity techniques

Peng Lu, Hong Chuan Yang, Young Chai Ko

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Random unitary beamforming (RUB) is an attractive low-complexity transmission scheme for multiple-inputmultiple-output (MIMO) broadcast channels. In this paper, we study the sum-rate performance of RUB-based multiuser MIMO systems with receive diversity. Two combining techniques, i.e., selection combining (SC) and optimum combining (OC), are employed to reduce feedback load and improve sum-rate performance. With these combining techniques, each user only needs to feed back one beam index and the corresponding output signal-to-interference-plus-noise ratio (SINR). For the SC scheme, we derive the statistics of the output SINR and the exact analytical expression of the sum rate. For the OC scheme, we develop an upper bound of the sum rate in the high-signal-to-noise-ratio (SNR) region. The bound is shown to be tight for the case of a moderate number of users, but the number of users must be at least five times the number of transmit antennas. Selected numerical examples show that the proposed design greatly enhances the sum-rate performance while maintaining low feedback load.

Original languageEnglish
Article number5272671
Pages (from-to)490-494
Number of pages5
JournalIEEE Transactions on Vehicular Technology
Issue number1
Publication statusPublished - 2010 Jan

Bibliographical note

Funding Information:
Manuscript received August 22, 2008; revised November 26, 2008, March 19, 2009, June 6, 2009, and July 15, 2009. First published September 29, 2009; current version published January 20, 2010. This paper was presented in part at the IEEE Global Communications Conference, New Orleans, LA, November 30–December 4, 2008. This work was supported in part by startup funds from the University of Victoria and in part by a Discovery Grant from the National Science and Engineering Research Council of Canada. The review of this paper was coordinated by Prof. E. Bonek.


  • Multiple-input-multiple-output (MIMO) broadcast channels
  • Optimum combining (OC)
  • Random unitary beamforming (RUB)
  • Selection combining (SC)
  • Sum-rate analysis

ASJC Scopus subject areas

  • Automotive Engineering
  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Applied Mathematics


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