Network model for evaluating the performance of reciprocal channel-based key establishment with coupled antennas

Prior work on multi-antenna wireless communication has produced practical yet rigorous signal models that can account for the impact of antenna array mutual coupling and sophisticated circuit noise contributions. However, these models have not yet been extended to the case of systems that generate secret encryption keys based on the reciprocal electromagnetic propagation of multipath channels. This work performs this extension, building upon previously developed network models and augmenting them to accommodate considerations unique to the key establishment protocol. Simulation results demonstrate the impact on the achievable performance of mutual coupling and of the impedance matching network that interfaces the coupled array to the accompanying circuitry.