Short Block-length Codes for Ultra-Reliable Low-Latency Communications

TL;DR

This paper reviews short block-length channel coding techniques for ultra-reliable low-latency communications in 5G and beyond, highlighting challenges and potential solutions for achieving extremely low latency and high reliability.

Contribution

It provides a comprehensive overview and comparison of coding techniques for short blocks in URLLC, and discusses new research directions and solutions.

Findings

Short block codes are essential for URLLC due to latency constraints.

Traditional codes underperform at short block lengths for URLLC.

Several promising coding strategies and research directions are identified.

Abstract

This paper reviews the state of the art channel coding techniques for ultra-reliable low latency communication (URLLC). The stringent requirements of URLLC services, such as ultra-high reliability and low latency, have made it the most challenging feature of the fifth generation (5G) mobile systems. The problem is even more challenging for the services beyond the 5G promise, such as tele-surgery and factory automation, which require latencies less than 1ms and failure rate as low as $10^{-9}$. The very low latency requirements of URLLC do not allow traditional approaches such as re-transmission to be used to increase the reliability. On the other hand, to guarantee the delay requirements, the block length needs to be small, so conventional channel codes, originally designed and optimised for moderate-to-long block-lengths, show notable deficiencies for short blocks. This paper provides an overview on channel coding techniques for short block lengths and compares them in terms of performance and complexity. Several important research directions are identified and discussed in more detail with several possible solutions.