Secure Transmission in Cell-Free Massive MIMO With RF Impairments and Low-Resolution ADCs/DACs

Abstract

This paper considers the secure transmission in a cell-free massive MIMO system with imperfect radio frequency (RF) chains and low-resolution analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) at both access points (APs) and legitimate users, where an active eavesdropper attempts to wiretap the confidential data. The Gaussian RF impairment model (GRFIM) and additive quantization noise model (AQNM) are used to evaluate the impacts of the RF impairments and low resolution ADCs/DACs, respectively. The analytical results of the linear minimum mean square error (MMSE) channel estimation show that there is nonzero floor on the estimation error with respect to the RF impairments, ADC/DAC precision and the pilot power of the eavesdropper which is different from the conventional case with perfect transceiver. Then, a tractable closed-form expression for the ergodic secrecy rate is obtained with respect to key system parameters, such as the antenna number per AP, the AP number, user number, quality factors of the ADC/DAC and the RF chain, pilot signal power of the eavesdropper, etc. Moreover, a compensation algorithm between the imperfect RF components and the inexpensive coarse ADCs/DACs is also presented. Finally, numerical results are provided to illustrate the efficiency of the achieved expressions and the devised algorithm, and show the effects of RF impairments and low resolution ADC/DAC on the secrecy performance.

A Unified Framework for Full-Duplex Massive MIMO Cellular Networks With Low Resolution Data Converters

“…This factor, for example, rejects about 9 dB of interference at a CDF of 80%. Although the increase of this factor is important, the SINR is limited by the pilot contamination which is corroborated by (56).…”

“…Recent work [10], [51]- [53] used an AQNM to model the nonlinear distortion as a gain plus additive noise for mmWave signals for an arbitrary number of ADC bits. In addition, authors in [54]- [56] derived Gaussian approximations using Bussgang Theory to linearize the nonlinear quantization distortion which is quite similar to the AQNM. The received signal (2) is processed by RF chains and then converted to the digital discrete-time domain by ADCs.…”

“…Proposition 6. With channel hardening, without full-duplexing (no IUI), with full-resolution and with a matched filter precoder, the output SINR of the k-th downlink user is given by (56).…”

Cooperative Beamforming With Artificial Noise Injection for Physical-Layer Security

“…Taking advantage of such a trade-off relationship, we can overcome the secrecy rate degradation with the simple data beamformer (i.e., t = 1) for Eve close to Bob. To obtain the precoding vector in (15), however, each VAA element should know CSI (or locations) of the other elements. For instance, the nth element of w(k) in ( 15) can be obtained by using all the elements of w D (k) and v(ϕ B , k).…”

Reconfigurable Intelligent Surface-Aided Cell-Free Massive MIMO with Low-Resolution ADCs: Secrecy Performance Analysis and Optimization

“…Under the assumption of low-resolution ADCs, the secrecy performance analysis and the power control in cell-free massive MIMO have been investigated in detail in [42]. Besides, the authors in [43] analyzed the effect of the RF impairments and low-resolution ADCs/DACs in secure cell-free massive MIMO system, where some key parameters on the security performance have been stuided and been verified via numerical results.…”