Impacts of Imperfect CSI and Transceiver Hardware Noise on the Performance of Full-Duplex DF Relay System With Multi-Antenna Terminals Over Nakagami-m Fading Channels

In this paper, we investigate the performance of a full-duplex (FD) relay system where multi-antennas are exploited at source and destination. Unlike previous works, the impacts of imperfect channel state information (I-CSI), transceiver hardware noise (THN), and residual self-interference (RSI) are taken into account. We mathematically derive the exact closed-form expressions of the outage probability (OP), symbol error rate (SER), and ergodic capacity (EC) of the FD relay system with I-CSI, THN, and RSI over Nakagami- $m$ fading channels. From the derived expressions, the performance of the considered system under the effects of three negative factors (I-CSI, THN, and RSI) is compared with that system in the case of all ideal factors (perfect channel state information (P-CSI), perfect transceiver hardware (P-TH) and perfect self-interference cancellation (P-SIC)), two ideal factors (P-CSI and P-TH, P-CSI and P-SIC, P-TH and P-SIC), or one ideal factor (P-CSI or P-TH or P-SIC). Numerical results show a strong impact of three negative factors on the OP, SER, and EC of the considered FD relay system, especially when the data transmission rate of the system and signal-to-noise ratio (SNR) are high. In particular, OP, SER, and EC go to the floors in the high SNR regime due to the three negative factors. Therefore, when I-CSI, THNs, and RSI exist in the FD relay system, we should use suitable source and relay transmission power to obtain excellent performance while saving energy consumption. Moreover, when two of the three negative factors are large enough, the remaining factor’s impact becomes weaker and may be neglected in certain circumstances.

I. Introduction

The fast development of wireless devices, especially for personal users, requires an increase in the capacity of wireless communication systems. Various new technologies such as multiple-input multiple-output (MIMO), full-duplex (FD), cognitive radio (CR), and non-orthogonal multiple access (NOMA) have been proposed to satisfy the capacity requirements of future wireless networks [1]–[4]. Since the MIMO transmission technique can provide high capacity and diversity order, it is not only deployed in the third and fourth generations (3G and 4G) but is also a promising candidate for the fifth-generation (5G) and beyond [5]. However, the hardware deployments and signal processing in MIMO systems, especially the personal devices, are very complex because of multiple radio frequency (RF) signals. Therefore, maximal ratio transmission (MRT) at the transmitter and maximal ratio combining (MRC) at the receiver have been proposed for the MIMO systems to solve these matters [6]. Besides reducing the complexity of MIMO systems, MRT/MRC techniques can significantly improve the system performance by providing the full diversity order. Therefore, applying MRT/MRC techniques in MIMO systems becomes popular in practice.