Transmit Antenna Selection for Physical-Layer Network Coding Based on Euclidean Distance

TL;DR

This paper analyzes error performance of transmit antenna selection schemes in physical-layer network coding for two-way relay channels, introducing a Euclidean distance based scheme that improves error performance and diversity order.

Contribution

It proposes a novel Euclidean distance based antenna selection scheme for PNC systems, outperforming traditional strongest channel schemes in error performance.

Findings

The strongest channel based scheme achieves a diversity order of 1 for M > 2.

The Euclidean distance based scheme outperforms the strongest channel scheme.

The ED scheme achieves a diversity order at least equal to the minimum number of antennas at the users.

Abstract

Physical-layer network coding (PNC) is now well-known as a potential candidate for delay-sensitive and spectrally efficient communication applications, especially in two-way relay channels (TWRCs). In this paper, we present the error performance analysis of a multiple-input single-output (MISO) fixed network coding (FNC) system with two different transmit antenna selection (TAS) schemes. For the first scheme, where the antenna selection is performed based on the strongest channel, we derive a tight closed-form upper bound on the average symbol error rate (SER) with $M$-ary modulation and show that the system achieves a diversity order of 1 for $M > 2$. Next, we propose a Euclidean distance (ED) based antenna selection scheme which outperforms the first scheme in terms of error performance and is shown to achieve a diversity order lower bounded by the minimum of the number of antennas at the two users.