Feasibility of Wireless Quantum Key Distribution in Indoor Environments

We propose and study the feasibility of wireless quantum key distribution (QKD) in indoor environments. Such systems are essential in providing wireless access to the developing quantum communications networks. We find a practical regime of operation, where, in the presence of background noise and loss, secret keys can be exchanged. Our findings identify the trade-off between the acceptable amount of background noise and the receiver field of view, where the latter determines the accessibility of the QKD system. In particular, we show that, with a proper setting, we can provide mobility for the QKD users without imposing stringent conditions on beam steering.