Hardware Impairments Aware Transceiver Design for Full-Duplex Amplify-and-Forward MIMO Relaying

Abstract

In this work we consider a full-duplex (FD) and amplify-and-forward (AF) relay with multiple antennas, where hardware impairments of the FD relay are taken into account. Due to the inter-dependency of the transmit relay power and the residual self-interference in an AF-FD relay, we observe a distortion loop that degrades the system performance when relay dynamic range is not high. In this regard, we analyze the relay function, and an optimization problem is formulated to maximize the signal to distortion-plus-noise ratio (SDNR) under relay and source transmit power constraints. Due to the problem complexity, we propose a gradient-projection-based (GP) algorithm to obtain an optimal solution. Moreover, a nonalternating sub-optimal solution is proposed by assuming a rank-1 relay amplification matrix, and separating the design of the relay process into multiple stages (MuStR1). The proposed MuStR1 method is then enhanced by introducing an alternating update over the optimization variables, denoted as AltMuStR1 algorithm. Numerical simulations show that compared to GP, the proposed (Alt)MuStR1 algorithms significantly reduce the required computational complexity at the expense of a slight performance degradation. Moreover, as the hardware impairments increase, or for a system with a high transmit power, the impact of applying a distortion-aware design is significant.

Hardware Impairments Aware Transceiver Design for Bidirectional Full-Duplex MIMO OFDM Systems

“…In this paper we study a bidirectional FD MIMO OFDM system 3 , where the impacts of hardware distortions leading to imperfect SIC and ICL are taken into account. Our main contributions, together with the paper organization are summarized as follows: leftmargin=* • In the seminal work by Day et al [12], an FD MIMO transceiver is modeled considering the impacts of hardware distortions in transmit/receiver chains, which is then extensively used for the purpose of FD system design and performance analysis, e.g., [16], [19], [30]- [34]. In the first step, we extend the available timedomain characterization of hardware distortions into an FD MIMO OFDM setup via a linear discrete Fourier 2 For instance, a high-power transmission in one of the subcarriers will result in a higher residual self-interference (RSI) in all of the sub-channels due to, e.g., a higher quantization and power amplifier noise levels.…”

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

“…In the Industry 4.0 era, wireless communications will play a key role in providing broadband connections for up to tens of billions of Internet of ings (IoT) devices. While existing technologies are hardly capable of meeting the spectrum requirements for such a large number of wireless devices, the in-band full-duplex (IBFD) communication technology which can double the spectrum e ciency is a promising solution [1][2][3][4][5][6][7][8][9][10][11]. However, although large e orts have been made recently to produce IBFD wireless devices, it is widely known that this type of communication is still a ected by residual self-interference (RSI) due to imperfect self-interference cancellation (SIC) [2][3][4]12].…”

“…However, more e orts still need to be done to achieve better RSI suppression. Wireless relaying is an emerging technology which can be used to improve coverage, reliability, and spectrum efciency has recently become a hot research topic [1,[3][4][5][6][7][8][9][10][11][15][16][17]. It is also expected to be widely employed for the IoT networks to support machine-to-machine (M2M) communications, in which wireless relaying is an important application.…”

“…e paper derived the self-interference matrix at the relay and proposed beam-forming schemes to maximize the signal-tointerference-plus-noise power ratio (SINR), thus improving the system performance. e works [11,15] analyzed the impact of hardware impairment at the relay node on the system performance.…”

“…e above overview showed that the outage performance of the FD relay systems suffered an outage floor in the high SNR regime and optimal power allocation could be used to improve the system performance and avoid such outage floor. However, most previous studies have been done for the ideal hardware systems except those in [11,15,18]. ese works considered an additional impact of imperfect hardware but only at the relay node.…”