Random ISAC Signals Deserve Dedicated Precoding

Fuente: arXiv
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Main Authors: Lu, Shihang, Liu, Fan, Dong, Fuwang, Xiong, Yifeng, Xu, Jie, Liu, Ya-Feng, Jin, Shi
Format: Preprint
Published: 2023
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_version_ 1866913291548229632
author Lu, Shihang
Liu, Fan
Dong, Fuwang
Xiong, Yifeng
Xu, Jie
Liu, Ya-Feng
Jin, Shi
author_facet Lu, Shihang
Liu, Fan
Dong, Fuwang
Xiong, Yifeng
Xu, Jie
Liu, Ya-Feng
Jin, Shi
contents Radar systems typically employ well-designed deterministic signals for target sensing, while integrated sensing and communications (ISAC) systems have to adopt random signals to convey useful information. This paper analyzes the sensing and ISAC performance relying on random signaling in a multi-antenna system. Towards this end, we define a new sensing performance metric, namely, ergodic linear minimum mean square error (ELMMSE), which characterizes the estimation error averaged over random ISAC signals. Then, we investigate a data-dependent precoding (DDP) scheme to minimize the ELMMSE in sensing-only scenarios, which attains the optimized performance at the cost of high implementation overhead. To reduce the cost, we present an alternative data-independent precoding (DIP) scheme by stochastic gradient projection (SGP). Moreover, we shed light on the optimal structures of both sensing-only DDP and DIP precoders. As a further step, we extend the proposed DDP and DIP approaches to ISAC scenarios, which are solved via a tailored penalty-based alternating optimization algorithm. Our numerical results demonstrate that the proposed DDP and DIP methods achieve substantial performance gains over conventional ISAC signaling schemes that treat the signal sample covariance matrix as deterministic, which proves that random ISAC signals deserve dedicated precoding designs.
format Preprint
id arxiv_https___arxiv_org_abs_2311_01822
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Random ISAC Signals Deserve Dedicated Precoding
Lu, Shihang
Liu, Fan
Dong, Fuwang
Xiong, Yifeng
Xu, Jie
Liu, Ya-Feng
Jin, Shi
Information Theory
Signal Processing
Radar systems typically employ well-designed deterministic signals for target sensing, while integrated sensing and communications (ISAC) systems have to adopt random signals to convey useful information. This paper analyzes the sensing and ISAC performance relying on random signaling in a multi-antenna system. Towards this end, we define a new sensing performance metric, namely, ergodic linear minimum mean square error (ELMMSE), which characterizes the estimation error averaged over random ISAC signals. Then, we investigate a data-dependent precoding (DDP) scheme to minimize the ELMMSE in sensing-only scenarios, which attains the optimized performance at the cost of high implementation overhead. To reduce the cost, we present an alternative data-independent precoding (DIP) scheme by stochastic gradient projection (SGP). Moreover, we shed light on the optimal structures of both sensing-only DDP and DIP precoders. As a further step, we extend the proposed DDP and DIP approaches to ISAC scenarios, which are solved via a tailored penalty-based alternating optimization algorithm. Our numerical results demonstrate that the proposed DDP and DIP methods achieve substantial performance gains over conventional ISAC signaling schemes that treat the signal sample covariance matrix as deterministic, which proves that random ISAC signals deserve dedicated precoding designs.
title Random ISAC Signals Deserve Dedicated Precoding
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2311.01822