A
system, method, and
signal provided, characterized by transmitting and receiving a
stream of samples. On the transmitting side (Alice), generating a
stream of samples for driving a
transmitter, each sample having an in-phase (1) component and a quadrature (Q) component, wherein the
stream of samples is generated from a stream of
pilot symbols and a stream of QKD symbols, wherein the
pilot symbols belong to an alphabet of M
pilot symbols and the QKD symbols belong to an alphabet of N QKD symbols; mapping a pilot symbol of the stream of pilot symbols to a group of
constellation points in accordance with a one-to-one mapping from the alphabet of M pilot symbols to M groups of
constellation points in an I-Q space, wherein each of the M groups comprises N
constellation points; and mapping a QKD symbol of the stream of QKD symbols to a constellation point in the I-Q space in accordance with a one-to-one mapping from the alphabet of N QKD symbols to the N constellation points of the group of constellation points to which the pilot symbol is mapped. On the receiving end, obtaining the stream of samples, the stream of samples representing a component of a received
signal, each sample having an in-phase (1) component and a quadrature (Q) component; generating a stream of pilot symbols from the stream of samples, in accordance with a one-to-one mapping from M groups of constellation points in an I-Q space to an alphabet of M pilot symbols, wherein each of the M groups comprises N constellation points; and generating a stream of
quantum key distribution (QKD) symbols from the stream of samples, in accordance with an M-to-one mapping from a set of M*N constellation points of the M groups to an alphabet of N QKD symbols, wherein the M-to-one mapping from the set of M*N constellation points to the alphabet of N QKD symbols comprises, for each respective group of the M groups, a one-to-one mapping from the N constellation points of the respective group to the alphabet of N QKD symbols.