To Code or Not to Code Across Time: Space-Time Coding with Feedback

Abstract— Space-time codes leverage the availability of multiple antennas to enhance the reliability of communication over wireless channels. While space-time codes have initially been designed with a focus on open-loop systems, recent technological advances have enabled the possibility of low-rate feedback from the receiver to the transmitter. The focus of this paper is on the implications of this feedback in a single-user multi-antenna system with a general model for spatial correlation. We assume a limited feedback model, that is, a coherent receiver and statistical knowledge at both the ends, along with B bits of error-free quantized channel information at the transmitter. We study space-time coding with a family of linear dispersion (LD) codes that meet an additional orthogonality constraint so as to ensure low-complexity decoding. Our results show that, when the number of bits of feedback (B) is small, a space-time coding scheme that is equivalent to beamforming and does not co...

• Type: Journal
• Year: 2007
• Where: CORR
• Authors: Che Lin, Vasanthan Raghavan, Venugopal V. Veeravalli
• Keywords: CORR 2007, Education, Error-free Quantized Channel, Feedback, Space-time