A Robust Physical Layer Key Generation Algorithm for Ultra-Wideband Ranging Process

Ultra-wideband (UWB) technology has been widely used for low-cost accurate ranging and positioning. To ensure communication security, a secret key must be derived before every ranging session. However, this process introduces significant latency and requires additional hardware. Therefore, this letter proposes a low-cost physical layer key generation algorithm that leverages the characteristics of multi-path channels for authentication and encryption. By effectively utilizing channel impulse response (CIR) and channel features, the proposed approach significantly reduces the key disagreement rate (KDR). Moreover, a scrambled timestamp sequence (STS) assisted error correction method is also proposed to further reduce the KDR. Simulation results demonstrate that, for a 128-bit physical key, the proposed scheme achieves a 0.5% KDR and over 83% STS matching rate at a 10 dB Signal to Noise Ratio (SNR). By utilizing several generation processes, the proposed algorithm can efficiently generate the physical layer key during the ranging session.