Precoding for secret key generation in multiple antenna channels with statistical channel state information

In future wireless communication systems, more and more small low-power mobile devices will communicate without infrastructure and internet access. In order to provide a lightweight yet powerful security mechanism, physical layer parameters can be used to generate secret keys for perfect secrecy. In this paper, we study the optimal operation of a multiple antenna link with statistical channel state information at all nodes for secret key generation. The impact of spatial correlation on the achievable secret key rates is characterized. Furthermore, the optimal pilot precoding during channel estimation is computed. Numerical simulations illustrate the results for selected scenarios.