A Poincar\'e Lower Bound Approach for Performance Trade-offs in MIMO ISAC Systems with Blockage

TL;DR

This paper introduces a Poincaré lower bound to analyze the performance trade-offs between sensing and communication in MIMO ISAC systems, addressing complex channel conditions and blockage effects.

Contribution

It proposes a novel Poincaré lower bound for sensing MSE and establishes an achievable rate-sensing trade-off in MIMO channels with blockage.

Findings

Derived a Poincaré lower bound for sensing MSE.

Established an achievable rate-sensing trade-off.

Provided an asymptotically optimal sensing strategy.

Abstract

Characterizing the performance trade-offs between sensing and communication subsystems is essential for enabling integrated sensing and communication systems. Various metrics exist for each subsystem; however, this study focuses on the ergodic capacity of the communication subsystem. Due to the complexity of deriving the sensing mean square error (MSE) and the inapplicability of the Bayesian Cram\'er-Rao Bound to channels with discrete or mixed distributions, this work proposes a Poincar\'e lower bound on the sensing MSE to address these issues. An achievable inner bound for the rate-sensing trade-off in a fading multiple-input multiple-output channel with additive white Gaussian noise and blockage probability is established. In addition, a strategy that is asymptotically optimal for sensing is provided.