Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Globecom Workshops (GC Wkshps)

A secret key generation method based on CSI in OFDM-FDD system

Xiaohua Wu, Yuexing Peng, Chunjing Hu, Hui Zhao, Lei Shu

Published Dec 1, 2013• 40 citations
Publisher

Abstract

Channel reciprocity is an inherent feature of time division duplex (TDD) system while in frequency division duplex (FDD) system it is limited due to different frequencies being used for the uplink and the downlink. As a consequence, channel reciprocity-based secret generating methods used in TDD systems cannot be applied directly to FDD systems. In this paper, we present a novel secret key generation method for FDD system, for which the communication pair estimate the channel state information (CSI) of the same time in the uplink by a specially designed forwarding strategy and generate the secret key from the CSI estimates. Numerical simulations are implemented to verify the effectiveness of the proposed method.

DOI
10.1109/glocomw.2013.6825173

Related papers

Secret key extraction based on uplink CFR estimation for OFDM-FDD system

Xiaohua Wu, Chunjing Hu, Yuexing Peng +2 more

Channel reciprocity is limited in frequency division duplex (FDD) system, and thus those channel reciprocity-based secret key extraction methods which are widely adopted in time division duplex (TDD) systems can hardly be implemented in FDD systems. In this paper, a novel secret key extraction method in OFDM-FDD system is proposed to achieve physical-layer security, by which the channel frequency response (CFR) in the uplink at the same time is estimated by the communication pair with the aid of a specially designed forwarding strategy based on confidential probing signal, and then the secret key is extracted from the CFR estimates. The effectiveness of the proposed method is verified by numerical simulations.

IEEE International Conference on Communication Technology (ICCT)•Nov 1, 2013•1 citation

CSI-Driven Physical Layer Secret Key Generation for FDD Systems

Ehsan Olyaei Torshizi, Anas Alashqar, Werner Henkel

Physical Layer Secret Key Generation (PLSKG), which utilizes wireless channel reciprocity, is increasingly adopted to secure wireless communications. In Time Division Duplexing (TDD) systems, the inherent channel reciprocity facilitates the generation of cryptographic keys without requiring a key exchange process. Conversely, Frequency Division Duplexing (FDD) systems present greater challenges for key generation due to the use of distinct frequency bands for uplink and downlink, resulting in differing frequency responses. In this paper, we address this challenge by modeling the channel along with connecting cables as a two-port network and utilizing the reciprocity principles applicable to such networks within the same frequency range. For key generation, we construct the channel profile for each FDD band by utilizing the amplitude of the bidirectional scattering parameters S12and S21in two closely spaced FDD bands, thereby ensuring the required reciprocity in FDD systems. To assess the practicality of the proposed scheme, we analyze its performance across various indoor scenarios and compare it with other key generation schemes using multiple performance indicators. The comparative results confirm the feasibility and effectiveness of our scheme in terms of randomness and key disagreement ratio.

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)•Sep 1, 2025•0 citations

Secret Key Generation Scheme Based on Generative Adversarial Networks in FDD Systems

Zongyue Hou, Xinwei Zhang

In frequency division duplexing (FDD) systems, the uplink and downlink transmit information in different frequency bands, so it is difficult to use channel reciprocity to generate secret keys. Existing key generation methods for FDD systems have excessive overhead and security problems. This paper uses deep learning to predict the downlink channel state information (CSI) from the uplink CSI, so that two users can generate highly similar downlink CSI in FDD systems. We propose a key generation scheme based on boundary equilibrium generative adversarial network (BEGAN), including channel estimation, reciprocal channel feature construction, quantization, information reconciliation and privacy amplification. Numerical simulation results are presented to verify the feasibility and effectiveness of the proposed scheme.

IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS)•May 10, 2021•9 citations

Reciprocity and Secret Key Generation for FDD Systems using Non-Linear Quantization

Ehsan Olyaei Torshizi, Werner Henkel

Secret key generation based on wireless channel reciprocity has received quite some attention, recently. Channel reciprocity as an inherent feature of time division duplexing (TDD) systems leads to creating cryptographic keys without the need for a key exchange procedure. Using different carrier frequencies for the uplink and the downlink, however, means that there is no such symmetry in the frequency response of frequency division duplex (FDD) systems and it makes the key generation for these systems challenging. In this paper, we use the phase differences between neighboring antennas as a frequency-independent channel parameter that provides the required reciprocity in FDD systems. For our studies, we consider neighboring frequency ranges for both directions, which should result in a continuous curve through the two frequency ranges in the two directions. For denoising we use a polynomial curve fitting procedure on the phase differences between antennas. Moreover, we propose a non-linear scheme to quantize the midpoint between the two frequency ranges with the two measurement directions. As a consequence, in contrast to using a linear scheme, the proposed framework would be highly desirable for secret key applications as it gives rise to a more uniform distribution for the resulting histogram over the quantization intervals. Numerical simulation results are shown to verify the effectiveness of the proposed method.

IEEE Globecom Workshops (GC Wkshps)•Dec 4, 2022•8 citations

Improving secret key generation for wireless communications in FDD mode

Ali M. Allam

Summary Most recent research on channel‐based key generation oriented to time division duplex system because the channel reciprocity feature is applied directly for secret key generation. Most of commercial cellular systems depend on frequency division duplex (FDD) systems. In this paper, we investigate the impact of uplink and downlink of FDD systems for the generation of shared secret keys between two parties in the presents of passive eavesdropper. In addition, we are considering improving the rate of the secret key for wireless communication in FDD mode. The main idea is to use the fading coefficient of the channels between the relay and other parties as an additional random common source for the secret key generation. Also, explore the using of channel estimation techniques to reduce the channel training sequence and study its effect on the generation of shared key for wireless communications in FDD mode. We derive the upper bound of the generated shared key rate for four scenarios and give numerical examples to reveal the performance of our suggested improvement approaches.

International Journal of Communication Systems•Mar 30, 2018•2 citations

Channel-based Secret Key Establishment for FDD Wireless Communication Systems

Ali M.

Most of current research on channel-based key generation focused on a time division duplex (TDD) system as the channel reciprocity factor applied directly to the generation of a secret key.However, most of commercial cellular systems rely on a frequency division duplex (FDD) mode.In this paper, we study the utilization of the uplink and downlink of FDD systems for the generation of common secret key between two users in the presents of inactive eavesdropper.The clue of our work is to explore the fading gain of the wireless channel between two users to generate a symmetric key.We develop the upper bound of the generation rate for shared key of the suggested mechanism and give numerical examples to show the performance of our suggested approach.

Communications on Applied Electronics•Nov 29, 2017•15 citations
Channel reciprocity is an inherent feature of time division duplex (TDD) system while in frequency division duplex (FDD) system it is limited due to different frequencies being used for the uplink and the downlink. As a consequence, channel reciprocity-based secret generating methods used in TDD systems cannot be applied directly to FDD systems. In this paper, we present a novel secret key generation method for FDD system, for which the communication pair estimate the channel state information (CSI) of the same time in the uplink by a specially designed forwarding strategy and generate the secret key from the CSI estimates. Numerical simulations are implemented to verify the effectiveness of the proposed method.
Channel reciprocity is limited in frequency division duplex (FDD) system, and thus those channel reciprocity-based secret key extraction methods which are widely adopted in time division duplex (TDD) systems can hardly be implemented in FDD systems. In this paper, a novel secret key extraction method in OFDM-FDD system is proposed to achieve physical-layer security, by which the channel frequency response (CFR) in the uplink at the same time is estimated by the communication pair with the aid of a specially designed forwarding strategy based on confidential probing signal, and then the secret key is extracted from the CFR estimates. The effectiveness of the proposed method is verified by numerical simulations.
Physical Layer Secret Key Generation (PLSKG), which utilizes wireless channel reciprocity, is increasingly adopted to secure wireless communications. In Time Division Duplexing (TDD) systems, the inherent channel reciprocity facilitates the generation of cryptographic keys without requiring a key exchange process. Conversely, Frequency Division Duplexing (FDD) systems present greater challenges for key generation due to the use of distinct frequency bands for uplink and downlink, resulting in differing frequency responses. In this paper, we address this challenge by modeling the channel along with connecting cables as a two-port network and utilizing the reciprocity principles applicable to such networks within the same frequency range. For key generation, we construct the channel profile for each FDD band by utilizing the amplitude of the bidirectional scattering parameters S12and S21in two closely spaced FDD bands, thereby ensuring the required reciprocity in FDD systems. To assess the practicality of the proposed scheme, we analyze its performance across various indoor scenarios and compare it with other key generation schemes using multiple performance indicators. The comparative results confirm the feasibility and effectiveness of our scheme in terms of randomness and key disagreement ratio.
In frequency division duplexing (FDD) systems, the uplink and downlink transmit information in different frequency bands, so it is difficult to use channel reciprocity to generate secret keys. Existing key generation methods for FDD systems have excessive overhead and security problems. This paper uses deep learning to predict the downlink channel state information (CSI) from the uplink CSI, so that two users can generate highly similar downlink CSI in FDD systems. We propose a key generation scheme based on boundary equilibrium generative adversarial network (BEGAN), including channel estimation, reciprocal channel feature construction, quantization, information reconciliation and privacy amplification. Numerical simulation results are presented to verify the feasibility and effectiveness of the proposed scheme.
Secret key generation based on wireless channel reciprocity has received quite some attention, recently. Channel reciprocity as an inherent feature of time division duplexing (TDD) systems leads to creating cryptographic keys without the need for a key exchange procedure. Using different carrier frequencies for the uplink and the downlink, however, means that there is no such symmetry in the frequency response of frequency division duplex (FDD) systems and it makes the key generation for these systems challenging. In this paper, we use the phase differences between neighboring antennas as a frequency-independent channel parameter that provides the required reciprocity in FDD systems. For our studies, we consider neighboring frequency ranges for both directions, which should result in a continuous curve through the two frequency ranges in the two directions. For denoising we use a polynomial curve fitting procedure on the phase differences between antennas. Moreover, we propose a non-linear scheme to quantize the midpoint between the two frequency ranges with the two measurement directions. As a consequence, in contrast to using a linear scheme, the proposed framework would be highly desirable for secret key applications as it gives rise to a more uniform distribution for the resulting histogram over the quantization intervals. Numerical simulation results are shown to verify the effectiveness of the proposed method.
Summary Most recent research on channel‐based key generation oriented to time division duplex system because the channel reciprocity feature is applied directly for secret key generation. Most of commercial cellular systems depend on frequency division duplex (FDD) systems. In this paper, we investigate the impact of uplink and downlink of FDD systems for the generation of shared secret keys between two parties in the presents of passive eavesdropper. In addition, we are considering improving the rate of the secret key for wireless communication in FDD mode. The main idea is to use the fading coefficient of the channels between the relay and other parties as an additional random common source for the secret key generation. Also, explore the using of channel estimation techniques to reduce the channel training sequence and study its effect on the generation of shared key for wireless communications in FDD mode. We derive the upper bound of the generated shared key rate for four scenarios and give numerical examples to reveal the performance of our suggested improvement approaches.
Most of current research on channel-based key generation focused on a time division duplex (TDD) system as the channel reciprocity factor applied directly to the generation of a secret key.However, most of commercial cellular systems rely on a frequency division duplex (FDD) mode.In this paper, we study the utilization of the uplink and downlink of FDD systems for the generation of common secret key between two users in the presents of inactive eavesdropper.The clue of our work is to explore the fading gain of the wireless channel between two users to generate a symmetric key.We develop the upper bound of the generation rate for shared key of the suggested mechanism and give numerical examples to show the performance of our suggested approach.