Abstract
In this paper, we investigate the secrecy rate of finite-alphabet communications over multiple-input-multiple-output-multiple-antenna eavesdropper (MIMOME) channels. Traditional precoding designs based on Gaussian input assumption may lead to substantial secrecy rate loss when the Gaussian input is replaced by practical finite-alphabet input. to address this issue, we investigate linear precoding designs to directly maximize the secrecy rate for MIMOME systems under the constraint of finite-alphabet input. by exploiting the theory of Karush-Kuhn-Tucker (KKT) analysis and matrix calculus, we first present necessary conditions of the optimal precoding design when instantaneous channel-state information (CSI) of the eavesdropper is known at the transmitter. in this light, an iterative algorithm for finding the optimal precoding matrix is developed, utilizing a gradient decent method with backtracking line search. Moreover, we find that the beamforming design in MIMONE systems, which is a secrecy-capacity-achieving approach for Gaussian signaling, no longer provides the maximum secrecy rate for finite-alphabet input data. This case is substantially different from the Gaussian input case. in addition, we derive the closed-form results on the precoding matrix, which maximizes the secrecy rate in the low signal-to-noise ratio (SNR) region, and reveal the optimal precoding structure in the high-SNR region. a novel jamming signal generation method that draws on the CSI of the eavesdropper to additionally increase the secrecy rate is further proposed. the precoding design with only statistical CSI of the eavesdropper available at the transmitter is also considered. Numerical results show that the proposed designs provide significant gains over recent precoding designs through a power control policy and the precoding design with the Gaussian input assumption in various scenarios. © 2012 IEEE.
Recommended Citation
Y. Wu et al., "Linear Precoding for Finite-alphabet Signaling over MIMOME Wiretap Channels," IEEE Transactions on Vehicular Technology, vol. 61, no. 6, pp. 2599 - 2612, article no. 6187751, Institute of Electrical and Electronics Engineers, Jul 2012.
The definitive version is available at https://doi.org/10.1109/TVT.2012.2195339
Department(s)
Electrical and Computer Engineering
Keywords and Phrases
Finite alphabet; multiple-input-multiple-output-multiple-antenna eavesdropper (MIMOME); transmit precoding; wiretap channel
International Standard Serial Number (ISSN)
0018-9545
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Institute of Electrical and Electronics Engineers, All rights reserved.
Publication Date
23 Jul 2012
Comments
National Science Foundation, Grant 0520126