Huanhuan Song

Associating MIMO beamforming with security codes to achieve unconditional communication security

This study investigates the framework of associating multiple-input–multiple-output (MIMO) beamforming with secure code to achieve unconditional secure communications in the wireless passive eavesdropping environment. The schemes are based on a two-step method under Wyners wiretap channel model. First, with MIMO transmit beamforming, one can utilise the spatial degree of freedom to cripple eavesdroppers’ interceptions even when he does not know the eavesdroppers channel state information. Consequently, by taking the threshold characteristics of the secure code, the legitimate receivers will continue to extend an average bit error rate advantage over eavesdroppers when they share similar conditions (background noise power and channel gains). By this way, the proposed system could achieve almost zero information obtained by the eavesdroppers while still keeping rather lower error transmissions for the main channel. A profound theoretical analysis for the MIMO advantage channel and the exact closed-form expressions of secrecy outage probability for the secure code joint system are presented. The authors launch extensive experiments to verify the proposed security systems and demonstrate its feasibility and implement ability.

The Rayleigh Fading Channel Prediction via Deep Learning

This paper presents a multi-time channel prediction system based on backpropagation (BP) neural network with multi-hidden layers, which can predict channel information effectively and benefit for massive MIMO performance, power control, and artificial noise physical layer security scheme design. Meanwhile, an early stopping strategy to avoid the overfitting of BP neural network is introduced. By comparing the predicted normalized mean square error (NMSE), the simulation results show that the performances of the proposed scheme are extremely improved. Moreover, a sparse channel sample construction method is proposed, which saves system resources effectively without weakening performances.

The performance of the MIMO physical layer security system with imperfect CSI

It is an important approach for achieving secure physical layer transmission using beamforming technology of multi-antenna, most of the transmission models are built on the perfect channel estimation model. The paper studies the secure physical layer transmission of multi-antenna beamforming with imperfect channel estimation information (CSI) and discusses the realization of the physical layer security in the actual communication environment with channel estimation error. We build a secure physical layer transmission model using beamforming technology of multi-antenna combined with SVD precoding technology, and we also prove the realization of the model with simulation under imperfect CSI.

Using Basis Expansion Model for Physical Layer Authentication in Time-Variant System

In this paper a physical layer authentication method is proposed to suit to time-variant wireless channels by taking advantage of the varied mutually orthogonal basis functions and the constant basis coefficients to approximate the state of separable paths, in which each sampling values of separable paths is related within a block transmission time in time-variant channels. Simulation experiments in orthogonal frequency division multiplexing (OFDM) system proves the validity of the novel authentication method. The novel method makes 2-4dB improvement compared to the physical-layer authentication using conventional Least Square (LS) channel sounding.