Short-Packet Two-Way Amplify-and-Forward Relaying

TL;DR

This paper analyzes short-packet amplify-and-forward two-way relay networks, deriving error rate expressions for 2TS and 3TS schemes under finite blocklength, and compares their performance to guide scheme selection.

Contribution

It provides approximate and asymptotic error rate formulas for 2TS and 3TS schemes in short-packet relay networks, and identifies conditions favoring each scheme.

Findings

3TS scheme performs better at lower relay power and higher SNR differences.

Derived critical blocklength for scheme superiority based on sum-BLER.

Validated theoretical results with extensive simulations.

Abstract

This letter investigates an amplify-and-forward two-way relay network (TWRN) for short-packet communications. We consider a classical three-node TWRN consisting of two sources and one relay. Both two time slots (2TS) scheme and three time slots (3TS) scheme are studied under the finite blocklength regime. We derive approximate closed-form expressions of sum-block error rate (BLER) for both schemes. Simple asymptotic expressions for sum-BLER at high signal-to-noise ratio (SNR) are also derived. Based on the asymptotic expressions, we analytically compare the sum-BLER performance of 2TS and 3TS schemes, and attain an expression of critical blocklength, which can determine the performance superiority of 2TS and 3TS in terms of sum-BLER. Extensive simulations are provided to validate our theoretical analysis. Our results discover that 3TS scheme is more suitable for a system with lower relay transmission power, higher differences between the average SNR of both links and relatively lower requirements on data rate and latency.