Institute of Electrical & Electronic Engineers
Fundamental limits of secret-key generation over a two-way, reciprocal and block fading wireless channel are investigated. Only statistical Channel State Information (CSI) of the main channel is assumed to be available, whereas the eavesdropper has perfect CSI of its own channel. The authors establish upper and lower bounds on the secret-key generation capacity with public discussion. The upper bound can be expressed as a sum of two terms - one of the terms arises due to channel reciprocity, while the other term arises due to the communication. In the limit of long coherence period, the contribution from channel reciprocity vanishes to zero, whereas the other term prevails.