On the Performance Tradeoff of an ISAC System with Finite Blocklength

TL;DR

This paper analyzes the fundamental performance tradeoff between sensing and communication in a SISO ISAC system with finite blocklength, deriving bounds and asymptotic behavior to guide system design.

Contribution

It introduces the rate-error tradeoff as a key metric, derives bounds, and analyzes the asymptotic behavior of the tradeoff in finite blocklength ISAC systems.

Findings

Achievability and converse bounds for the rate-error tradeoff are established.

The performance tradeoff diminishes as blocklength increases, approaching zero asymptotically.

Simulation results validate the theoretical bounds and asymptotic analysis.

Abstract

Integrated sensing and communication (ISAC) has been proposed as a promising paradigm in the future wireless networks, where the spectral and hardware resources are shared to provide a considerable performance gain. It is essential to understand how sensing and communication (S\&C) influences each other to guide the practical algorithm and system design in ISAC. In this paper, we investigate the performance tradeoff between S\&C in a single-input single-output (SISO) ISAC system with finite blocklength. In particular, we present the system model and the ISAC scheme, after which the rate-error tradeoff is introduced as the performance metric. Then we derive the achievability and converse bounds for the rate-error tradeoff, determining the boundary of the joint S\&C performance. Furthermore, we develop the asymptotic analysis at large blocklength regime, where the performance tradeoff between S\&C is proved to vanish as the blocklength tends to infinity. Finally, our theoretical analysis is consolidated by simulation results.