Linear shrinkage receiver for slow fading channels under imperfect channel state information

TL;DR

This paper proposes a linear shrinkage receiver for SIMO slow fading channels with imperfect CSI, which reduces outage probability in finite antenna regimes and is optimal asymptotically, demonstrated through numerical results.

Contribution

It introduces a linear shrinkage approach to improve outage performance in slow fading channels with imperfect CSI, a novel method for such scenarios.

Findings

Linear shrinkage reduces outage probability for finite antennas.

LMMSE estimate is optimal asymptotically.

Numerical results confirm performance improvements.

Abstract

This paper studies receiver design in single-input multiple-output (SIMO) slow fading channels with imperfect channel state information (CSI) at the receiver only. Using generalized mutual information (GMI) as achievable rate, we study the outage behavior when the receiver employs certain generalized form of the nearest neighbor decoding rule. Our study reveals that linearly shrinking the linear minimum meansquared error (LMMSE) estimate of the CSI reduces the outage probability when the number of receive antennas is finite. Only in the asymptotic regime where the number of receive antennas grows without bound, the LMMSE estimate of the CSI minimizes the outage probability. Numerical results demonstrate that the proposed linear shrinkage receiver achieves evident outage probability reduction.