Equal Gain Transmission in Multiple-Input Multiple-Output Wireless Systems

Authors:

David J. Love and Robert W. Heath Jr

Reference:

Accepted to IEEE Trans. on Comm. February 2003. 

Abstract:

Multiple-input multiple-output (MIMO) wireless systems are of interest due to their ability to provide substantial gains in capacity and quality. This paper proposes equal gain transmission (EGT) to provide diversity advantage in MIMO systems experiencing Rayleigh fading. The applications of equal gain transmission with selection diversity combining, equal gain combining, and maximum ratio combining are addressed. It is proven that systems using equal gain transmission with any of these combining schemes achieve full diversity order when transmitting over a memoryless, flat fading matrix channel with independent entries. Since in practice full channel knowledge at the transmitter is difficult to realize, a quantized version of EGT is proposed. An algorithm to construct a beamforming vector codebook that guarantees full diversity order is presented. Monte Carlo simulation comparisons with various beamforming and combining systems illustrate the performance as a function of quantization.

Keywords:

Diversity methods, MIMO systems, Rayleigh channels, equal gain transmission.Diversity methods, MIMO systems, Rayleigh channels, equal gain transmission.

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