On the Performance Limits of Scalar Coding Over MISO Channels

TL;DR

This paper improves the understanding of scalar coding limits in MISO channels by tightening the universal performance loss bound from approximately 2.51 dB to 1.1 dB using combined randomized beamforming and space-time coding.

Contribution

It introduces a novel approach combining randomized beamforming with space-time codes to reduce the performance loss bound in scalar coding over MISO channels.

Findings

Performance loss bound reduced to ~1.1 dB

Bound holds for any number of antennas and channel gains

Enhanced scalar coding efficiency with combined techniques

Abstract

The performance limits of scalar coding for multiple-input single-output channels are revisited in this work. By employing randomized beamforming, Narula et al. demonstrated that the loss of scalar coding is universally bounded by ~ 2.51 dB (or 0.833 bits/symbol) for any number of antennas and channel gains. In this work, by using randomized beamforming in conjunction with space-time codes, it is shown that the bound can be tightened to ~ 1.1 dB (or 0.39 bits/symbol).