Is Synchronization a Bottleneck for Pilot-Assisted URLLC Links?

Fuente: arXiv
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Autores principales: Kislal, A. Oguz, Rajiv, Madhavi, Durisi, Giuseppe, Ström, Erik G., Mitra, Urbashi
Formato: Preprint
Publicado: 2024
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author Kislal, A. Oguz
Rajiv, Madhavi
Durisi, Giuseppe
Ström, Erik G.
Mitra, Urbashi
author_facet Kislal, A. Oguz
Rajiv, Madhavi
Durisi, Giuseppe
Ström, Erik G.
Mitra, Urbashi
contents We propose a framework to evaluate the so-called random-coding union bound with parameter $s$ (RCUs) on the achievable error probability in the finite-blocklength regime for a pilot-assisted transmission scheme operating over an imperfectly synchronized and memoryless block-fading waveform channel. Unlike previous results, which disregard the effects of imperfect synchronization, our framework utilizes pilots for both synchronization and channel estimation. Specifically, we provide an algorithm to perform joint synchronization and channel estimation, and verify its accuracy by observing its tightness in comparison with the Cramer-Rao bound. Then, we develop an RCUs bound on the error probability, which applies for a receiver that treats the estimates provided by the algorithm as accurate. Additionally, we utilize the saddlepoint approximation to provide a numerically efficient method for evaluating the RCUs bound in this scenario. Our numerical experiments verify the accuracy of the proposed approximation. Moreover, when the delays are modeled as fully dependent across fading blocks, numerical results indicate that the number of pilot symbols needed to estimate the fading channel gains to the level of accuracy required in ultra-reliable low-latency communication is also sufficient to acquire sufficiently good synchronization. However, when the delays are modeled as independent across blocks, synchronization becomes the bottleneck for the system performance.
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id arxiv_https___arxiv_org_abs_2401_09089
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Is Synchronization a Bottleneck for Pilot-Assisted URLLC Links?
Kislal, A. Oguz
Rajiv, Madhavi
Durisi, Giuseppe
Ström, Erik G.
Mitra, Urbashi
Information Theory
We propose a framework to evaluate the so-called random-coding union bound with parameter $s$ (RCUs) on the achievable error probability in the finite-blocklength regime for a pilot-assisted transmission scheme operating over an imperfectly synchronized and memoryless block-fading waveform channel. Unlike previous results, which disregard the effects of imperfect synchronization, our framework utilizes pilots for both synchronization and channel estimation. Specifically, we provide an algorithm to perform joint synchronization and channel estimation, and verify its accuracy by observing its tightness in comparison with the Cramer-Rao bound. Then, we develop an RCUs bound on the error probability, which applies for a receiver that treats the estimates provided by the algorithm as accurate. Additionally, we utilize the saddlepoint approximation to provide a numerically efficient method for evaluating the RCUs bound in this scenario. Our numerical experiments verify the accuracy of the proposed approximation. Moreover, when the delays are modeled as fully dependent across fading blocks, numerical results indicate that the number of pilot symbols needed to estimate the fading channel gains to the level of accuracy required in ultra-reliable low-latency communication is also sufficient to acquire sufficiently good synchronization. However, when the delays are modeled as independent across blocks, synchronization becomes the bottleneck for the system performance.
title Is Synchronization a Bottleneck for Pilot-Assisted URLLC Links?
topic Information Theory
url https://arxiv.org/abs/2401.09089