See preshared keys
eying) A digital modulation technique that uses two phases for a 0 or 1. Also called "binary PSK" (BPSK), it is the most basic form of phase shift keying. For example, quadrature PSK (QPSK) uses four phase shifts for each two bits of input. See phase modulation
Phase Shift Keying
PSK is a simple technique that uses two phases to represent 0 and 1.
QPSK uses four phases 90 degrees apart to represent four values in each two bits (0-4) of input.