Compressed Sensing Method for Secret Key Generation Based on MIMO Channel Estimation

In searching for alternative solutions of secret key generation in wireless networks, many physical-layer-based methods have been proposed. These methods exploit the inherent randomness and reciprocity of the multipath fading channel to generate secret keys. Multiple-antenna system provide higher key bit generation rate than single-antenna one because of more channel randomness. However, traditional MIMO key generation schemes produce prohibitively high bit mismatch. To address the tradeoff between key bit generation rate and key agreement probability, we propose a compressed sensing (CS) method for key generation in single carrier MIMO sparse multipath channel. Theory analysis shows that the CS-based key generation scheme provides high entropy key bits from fewer probes. Performance simulation reveals the proposed scheme achieves a high key agreement probability at a high key generation rate.