Information Bottleneck for an Oblivious Relay with Channel State Information: the Vector Case

TL;DR

This paper investigates the information bottleneck problem in MIMO channels with fading, proposing bounds and schemes to optimize relay processing under channel state information constraints.

Contribution

It introduces new bounds and practical schemes for the IB problem in MIMO channels with channel state information limitations.

Findings

Proposed upper bound assuming perfect CSI at no cost.

Developed simple symbol-by-symbol relay schemes.

Numerical results show schemes approach the upper bound.

Abstract

This paper considers the information bottleneck (IB) problem of a Rayleigh fading multiple-input multiple-out (MIMO) channel. Due to the bottleneck constraint, it is impossible for the oblivious relay to inform the destination node of the perfect channel state information (CSI) in each channel realization. To evaluate the bottleneck rate, we provide an upper bound by assuming that the destination node can get the perfect CSI at no cost and two achievable schemes with simple symbol-by-symbol relay processing and compression. Numerical results show that the lower bounds obtained by the proposed achievable schemes can come close to the upper bound on a wide range of relevant system parameters.