We propose a new closed-loop transmit diversity scheme for multiple-input-multiple-output (MIMO) diversity systems based on orthogonal space-time block coding (OSTBC). The receiver of the proposed scheme checks the output signal-to-noise ratio (SNR) of the space-time decoder against an output threshold and requests the transmitter to replace the transmit antenna resulting in the poorest path with an unused antenna if the output SNR is below the threshold. We provide some interesting statistical analysis and obtain closed-form expressions for the cumulative distribution function (cdf), the probability density function (pdf), and the moment-generating function of the received SNR. We show through numerical examples that the proposed scheme offers a significant performance gain with a very minimal feedback load over existing open-loop MIMO diversity systems, and for a properly chosen threshold, its performance is commensurate with a more complicated generalized-selection-combining-based transmit diversity system while requiring a much smaller feedback load.
Bibliographical noteFunding Information:
Manuscript received August 17, 2006; revised February 7, 2007, March 20, 2007, and March 21, 2007. This work was supported by the Ministry of Knowledge Economy, Korea, under the Information Technology Research Center (ITRC) support program supervised by the Institute of Information Technology Advancement (IITA) under Grant IITA-2008-C1090-0801-0037. This paper was presented in part at the IEEE International Symposium on Wireless Pervasive Computing, Phuket, Thailand, January 2006. The review of this paper was coordinated by Prof. N. Arumugam.
- Diversity techniques
- Fading channels
- Multiple-input-multiple-output (MIMO)
- Performance analysis
- Switched diversity
- Transmit diversity
ASJC Scopus subject areas
- Automotive Engineering
- Aerospace Engineering
- Electrical and Electronic Engineering
- Applied Mathematics