Regional robust secure precise wireless transmission design for multi-user UAV broadcasting system

Tong Shen,Zhu Han,Yongpeng Wu,Yan Lin,Feng Shu,Tingting Liu

doi:10.1186/s13638-020-01817-y

Abstract

In this paper, two regional robust secure precise wireless transmission (SPWT) schemes for multi-user unmanned aerial vehicle (UAV), (1)regional signal-to-leakage-and-noise ratio (SLNR) and artificial-noise-to-leakage-and-noise ratio (ANLNR) (R-SLNR-ANLNR) maximization and (2) point SLNR and ANLNR (P-SLNR-ANLNR) maximization, are proposed to tackle with the estimation errors of the target users’ location. In the SPWT system, the estimation error for SPWT cannot be ignored. However, the conventional robust methods in secure wireless communications optimize the beamforming vector in the desired positions only in statistical means and cannot guarantee the security for each symbol. The proposed regional robust schemes are designed for optimizing the secrecy performance in the whole error region around the estimated location. Specifically, with the known maximal estimation error, we define the target region and wiretap region. Then, we design an optimal beamforming vector and an artificial noise projection matrix, which achieve the confidential signal in the target area having the maximal power while only few signal power is conserved in the potential wiretap region. Instead of considering the statistical distributions of the estimated errors into optimization, we optimize the SLNR and ANLNR of the whole target area, which significantly decreases the complexity. Moreover, the proposed schemes can ensure that the desired users are located in the optimized region, which are more practical than the conventional methods. Simulation results show that our proposed regional robust SPWT design is capable of substantially improving the secrecy rate compared to the conventional non-robust method. The P-SLNR-ANLNR maximization-based method has the comparable secrecy performance with lower complexity than that of the R-SLNR-ANLNR maximization-based method.

Highlights

In the past decade, physical layer security (PLS) in wireless communications [1,2,3,4,5,6,7,8,9,10] have explosively developed because it is an alternative to encryption in the higher layer
4 Method based on point signal-to-leakage-and-noise ratio (SLNR) maximization the robust method based on regional SLNR and Artificial-noise-to-leakage-and-noise ratio (ANLNR) maximization has guaranteed a stable performance for users in the whole error region, a sum of confidential signal energy in the error region has to be calculated, which may bring a huge amount of calculation complexity
(2) The secrecy rate is related to the main lobe size and the estimation error region size; when antenna number need at most O (NT) and signal bandwidth B increase which lead the main lobe to be smaller, the secrecy rate reduced

Summary

Introduction

Physical layer security (PLS) in wireless communications [1,2,3,4,5,6,7,8,9,10] have explosively developed because it is an alternative to encryption in the higher layer. The authors in [19] proposed a secure unmanned aerial mobile edge computing system where multiple ground users offload large computing tasks to a nearby legitimate UAV in the presence of multiple eavesdropping UAVs with imperfect locations As another promising PLS technique, direction modulation (DM) [20,21,22,23] has attracted extensive attention since it is capable of projecting useful signals only into a predetermined direction, while making the constellation of the signal in other directions distort. Shu et al in [25] proposed a multi-user robust scheme in the DM system with the direction angle estimation error with a Gaussian distribution, while Gui et al of [26] proposed a robust DM method with Von Mises distributed direction angle estimation error in multi-cast scenario Another interesting proposal is a novel robust DM scheme of [27] based on main lobe-integration maximization. The security of these DM techniques is guaranteed only in the direction dimension, while the eavesdroppers in the desired direction may receive the confidential messages from the channel, even if in different distances, which may bring a serious challenging security problem

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Conclusion