Performance Analysis of Full-Duplex Amplify-and-Forward Relay System with Hardware Impairments and Imperfect Self-Interference Cancellation

Ba Cao Nguyen,Xuan Nam Tran

doi:10.1155/2019/4946298

Abstract

In this paper, we analyze the performance of a full-duplex (FD) amplify-and-forward (AF) relay system with imperfect hardware. Besides the aggregate hardware impairments of the imperfect transceiver, we also consider the impact of residual self-interference (RSI) due to imperfect cancellation at the FD relay node. An analytical framework for analyzing the system performance including exact outage probability (OP), asymptotic OP, and approximate symbol error probability (SEP) is developed. In order to tackle these impacts, we propose an optimal power allocation scheme which can improve the outage performance of the FD relay node, especially at the high signal-to-noise ratio (SNR) regime. Numerical results are presented for various evaluation scenarios and verified using the Monte Carlo simulations.

Highlights

In [5], asymptotic expressions of outage probability (OP) and symbol error rate (SER) were derived for the FD-AF relay system. e authors proposed optimal power allocation and relay location to minimize SER and reduce performance saturation. e work in [9] evaluated performance of an FD-AF cooperative communication system working over the Nakagami-m channel. e obtained results showed that this system could achieve certain gain depending on the relay processing delay, packet length, and the direct link gain
Main performance measures used for evaluation are OP, system throughput, and symbol error probability (SEP) under impact of both hardware impairment and residual self-interference (RSI). e impact of hardware impairment is illustrated by comparing with the case of ideal hardware, i.e., k1 kR 0, for various RSI scenarios
We analyzed the impacts of the hardware impairments and RSI on performance of the in-band full-duplex (IBFD)-AF relay system

Summary

System Model

Consider a typical FD-AF relay system depicted in Figure 1, which is comprised of two terminal nodes S1 and S2 and a relay R. e two terminal nodes S1 and S2 operate in the HD mode, while relay R in the FD mode. In the ideal case with perfect hardware and no distortion and residual SIC, the received signal at the relay R at time slot t is given as yR(t) h1Rx1(t) + zR(t),. In the case of nonideal hardware, impairment occurs at both the transmitter and receiver, resulting in distortion noises. Where ηSt1 (t) and ηRr (t) denote the distortion noises due to the transmitter hardware impairment at S1 and the receiver hardware impairment at R, respectively. In the case the system has perfect CSI, ηR is defined as η1, meaning ηR ∼ CN m(0e,nkt2RsPfRr)o.mHtehreeitnr,anksRmiitsterthhearadgwgraergeakteRt level at R of impairand the receiver hardware kSr2 at S2, and PR is the transmit power at R. e received signal at the relay node can be rewritten as follows: yR(t) h1Rx􏽥1(t) + h􏽥RRx􏽥R(t) + zR(t),. Where d ≜ k21 + k2R + k21k2R, d1 ≜ 1 + k21, and d2 ≜ 1 + k2R

Performance Analysis

Optimal Power Allocation for the Relay Node

Numerical Results

Conclusion