Impacts of Imperfect Channel State Information, Transceiver Hardware, and Self-Interference Cancellation on the Performance of Full-Duplex MIMO Relay System

Abstract

Imperfect channel state information (I-CSI) and imperfect transceiver hardware often happen in wireless communication systems due to the time-varying and random characteristics of both wireless channels and hardware components. The impacts of I-CSI and hardware impairments (HI) reduce not only the system performance but also the self-interference cancellation (SIC) capability of full-duplex (FD) devices. To investigate the system performance in realistic scenarios, in this paper, we consider the performance of an FD multiple-input multiple-output (MIMO) relay system under the effects of I-CSI, imperfect SIC (I-SIC), and imperfect transceiver hardware. We mathematically derive the exact closed-form expressions of the outage probability (OP) and ergodic capacity of the considered HI-FD-MIMO relay system over Rayleigh fading channels with the existence of I-CSI, I-SIC, and HI. Numerical results indicate that the performance in terms of OP and capacity reaches saturation faster, especially when the channel estimation error, the residual self-interference (RSI), and HI levels are remarkable. Therefore, various solutions for effectively reducing the channel estimation error, RSI, and HI levels in the HI-FD-MIMO relay system should be carried out to improve the system performance. All derived mathematical expressions are verified through Monte-Carlo simulations.

Self-Interference Channel Training for Full-Duplex Massive MIMO Systems

“…From (13), the BS can obtain , which is the estimate of , by applying the existing conventional linear estimator in the manner of the LS or minimum MSE (MMSE) [ 40 , 43 ]. For the other remaining SI channel vectors in , by using the nature of slowly-varying SI channels [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ], the BS can reuse the previous estimated SI channel vectors, i.e., where is the number of blocks passed after the last estimation of the i th SI channel vector. Consequently, the total estimated SI channel matrix at the n th block for the proposed partial training method is given as follows: …”

“…The level of SI cancellation and suppression depends highly on the estimation accuracy of the SI channel [ 29 , 30 , 31 ]. Therefore, improving the SI channel estimation accuracy is a key technical issue for FD systems, and several related studies have been conducted [ 32 , 33 , 34 , 35 , 36 ].…”

On Performance of Full-Duplex Decode-and-Forward Relay Systems with an Optimal Power Setting under the Impact of Hardware Impairments

“…It was shown in [21] that the one-way relay network has a lower outage floor than the counterpart network. Recently, HI was also considered in the IBFD relay systems [22][23][24][25][26][27]. In particular, the impact of HI on the spectral efficiency of a multipair massive MIMO twoway IBFD relay system was analyzed in [22].…”

“…The alternating optimization was then extended to design the bidirectional IBFD MIMO OFDM systems with linear precoding and decoding [26]. The performance of the IBFD relay system under the impact of hardware impairments, imperfect channel state information, and imperfect self-interference cancellation was analyzed in [25]. Antenna selection was proposed as a solution to compensate for the performance saturation of the MIMO spatial modulation IBFD relay system [27].…”

“…Wireless Communications and Mobile Computing of the relay node, the OP performance is significantly affected especially at the high SNR region. Figure 3 shows the achieved OP for the case with the direct link but without cooperation (Case 2) using analytical equations ( 24), (25), and (33) with σ 2 RSI /σ 2 R = 5 dB and the distortion factors k S 1 R = k RS 2 = 0:1 and Ω 1 = Ω 2 = 1. Since cooperation was not used, the signal from the source node to the destination node was regarded as interference.…”