Is Synchronization a Bottleneck for Pilot-Assisted URLLC Links?
Journal article, 2024

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.

URLLC

finite-blocklength information theory

pilot-assisted transmission

synchronization

channel estimation

Author

Ahmet Oguz Kislal

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Madhavi Rajiv

USC Viterbi School of Engineering

Giuseppe Durisi

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Erik Ström

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks

Urbashi Mitra

USC Viterbi School of Engineering

IEEE Transactions on Wireless Communications

15361276 (ISSN) 15582248 (eISSN)

Vol. In Press

Subject Categories

Telecommunications

Communication Systems

Signal Processing

DOI

10.1109/TWC.2024.3458090

More information

Latest update

10/2/2024