Enabling Deep Learning-based Physical-layer Secret Key Generation for FDD-OFDM Systems in Multi-Environments

TL;DR

This paper introduces deep transfer learning and meta-learning algorithms to improve physical-layer secret key generation in FDD-OFDM systems across multiple environments, addressing real-world variability.

Contribution

It proposes novel transfer learning and meta-learning methods for multi-environment key generation, enabling quick adaptation and improved performance over existing approaches.

Findings

Both algorithms enhance key generation performance compared to non-adaptive methods.

Meta-learning achieves better results with lower complexity than transfer learning.

Simulation and experiments validate the effectiveness of the proposed methods.

Abstract

Deep learning-based physical-layer secret key generation (PKG) has been used to overcome the imperfect uplink/downlink channel reciprocity in frequency division duplexing (FDD) orthogonal frequency division multiplexing (OFDM) systems. However, existing efforts have focused on key generation for users in a specific environment where the training samples and test samples follow the same distribution, which is unrealistic for real-world applications. This paper formulates the PKG problem in multiple environments as a learning-based problem by learning the knowledge such as data and models from known environments to generate keys quickly and efficiently in multiple new environments. Specifically, we propose deep transfer learning (DTL) and meta-learning-based channel feature mapping algorithms for key generation. The two algorithms use different training methods to pre-train the model in the known environments, and then quickly adapt and deploy the model to new environments. Simulation and experimental results show that compared with the methods without adaptation, the DTL and meta-learning algorithms both can improve the performance of generated keys. In addition, the complexity analysis shows that the meta-learning algorithm can achieve better performance than the DTL algorithm with less cost.