Lu, Tianyu, Chen, Liquan, Zhang, Junqing 
ORCID: 0000-0002-3502-2926, Chen, Chen and Hu, Aiqun
(2023)
Joint Precoding and Phase Shift Design in Reconfigurable Intelligent Surfaces-Assisted Secret Key Generation.
IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY, 18.
pp. 3251-3266.
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TIFS2023_KeyGen_RIS.pdf - Author Accepted Manuscript Download (628kB) | Preview |
Abstract
Physical layer key generation (PLKG) is a promising technique to establish symmetric keys between resource-constrained legitimate users. However, PLKG suffers from a low key rate in harsh environments where channel randomness is limited. To address the problem, reconfigurable intelligent surfaces (RISs) are introduced to reshape the channels by controlling massive reflecting elements, which can provide more channel diversity. In this paper, we design a channel probing protocol to fully extract the randomness from the cascaded channel, i.e., the channels through reflecting elements. We derive the analytical expressions of the key rate and design a water-filling algorithm based on the Karush-Kuhn-Tucker (KKT) conditions to find the upper bound. To find the optimal precoding and phase shift matrices, we propose an algorithm based on the Grassmann manifold optimization methods. The system is evaluated in terms of the key rate, bit disagreement rate (BDR) and randomness. Simulation results show that our protocols significantly improve the key rate as compared to existing protocols. Compared to multiple-antennas systems without a RIS, our proposed method achieves an average 9.51 dB performance gain when the side length of an element is 1/4 wavelength and the Rician factor is 0 dB.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Physical layer security, physical layer key generation, reconfigurable intelligent surface, key rate |
| Divisions: | Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 18 Apr 2023 07:35 |
| Last Modified: | 15 Mar 2024 14:44 |
| DOI: | 10.1109/TIFS.2023.3268881 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3169631 |
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