Secret key generation based on estimated channel state information for TDD-OFDM systems over fading channels

Peng, Yuexing, Wang, Peng, Xiang, Wei, and Li, Yonghui (2017) Secret key generation based on estimated channel state information for TDD-OFDM systems over fading channels. IEEE Transactions on Wireless Communications, 16 (8). pp. 5176-5186.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website:


One of the fundamental problems in cryptography is the generation of a common secret key between two legitimate parties to prevent eavesdropping. In this paper, we propose an information-theoretic secret key generation (SKG) method for time division duplexing (TDD)-based orthogonal frequency-division multiplexing (OFDM) systems over multipath fading channels. By exploring physical layer properties of the wireless medium, i.e., the reciprocity, randomness, and privacy features of the radio channel, an SKG method is proposed to maximize the number of secret bits given a target secret key disagreement ratio (SKDR). In the proposed SKG method, the phase information of the estimated channel state information (CSI) is distilled for SKG, and a special guard band (GB) scheme is designed to achieve the target SKDR with a small phase information loss. The proposed GB consists of both the amplitude GB (AGB) and phase GB (PGB), where the AGB is determined by the average signal-to-interference plus noise ratio (SINR), whereas the PGB adapts itself to the instantaneous SINR and thus incurs a smaller phase information loss in the higher SINR region. Analyses show that this GB scheme trades off a small loss of channel phase information for a better SKDR performance, and achieves a much larger number of quantization levels for a given SKDR due to the fact that the PGB decreases quickly as the SINR increases. Based on the performance analysis on the SKDR, the average secret key length, the phase information loss percentage (PILP), and the optimal GB and quantization level of the adaptive quantizor are derived for a given target SKDR. Both analytical and simulation results are presented to demonstrate the superiority of the proposed scheme for TDD-OFDM systems over frequency-selective fading channels.

Item ID: 50677
Item Type: Article (Research - C1)
ISSN: 1558-2248
Keywords: average secret key length (ASKL), orthogonal frequency-division multiplexing (OFDM), physical-layer security
Funders: National Natural Science Foundation of China (NNSFC), National Key Research and Development Project of China (NK), Australian Research Council (ARC)
Projects and Grants: NNSFC Grant 61171106, NK Grant 2015ZX03002009-004, ARC Grant DP150104019
Date Deposited: 20 Sep 2017 11:00
FoR Codes: 40 ENGINEERING > 4006 Communications engineering > 400608 Wireless communication systems and technologies (incl. microwave and millimetrewave) @ 100%
SEO Codes: 89 INFORMATION AND COMMUNICATION SERVICES > 8901 Communication Networks and Services > 890103 Mobile Data Networks and Services @ 100%
Downloads: Total: 1
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page