Secret Key Generation Exploiting Ultra-wideband Indoor Wireless Channel Characteristics

Existing algorithms of secret key generation from UWB channels have been researched abiding by frequency spectrum regulations of Federal Communications Commission. To investigate this issue complying with specifications of Chinese UWB frequency spectrum, we study a statistical characterization of Ultra-Wideband (UWB) channels for a residential scenario based on extensive measurements. Moreover, an efficient secret key generation mechanism exploiting multipath relative delay is developed, and the verification of this algorithm is conducted in both Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) UWB channels. Simulation results demonstrate that the number of multipath proportionally affects key generation rate and key-mismatch probability. In comparison to the conventional method using received signal strength (RSS) as a common random source, our mechanism achieves better performance in terms of common secret bit generation. The results also indicate communicating transceivers have a slightly lower key-mismatch probability in NLOS condition than in LOS condition, as NLOS channels can provide a larger number of multipath.