A first wireless transceiver for a wireless telecommunications network, the wireless telecommunications network having a second wireless transceiver, the first wireless transceiver comprising: an electromagnetic field receiver, the electromagnetic field receiver including a first optical transmitter, a second optical transmitter, and a transmission medium, wherein the first optical transmitter is configured to transmit a probe signal via the transmission medium at a probe frequency and the second transmitter is configured to transmit a coupling signal via the transmission medium at a coupling frequency, wherein the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state and the coupling frequency is set to excite electrons of the transmission medium to a predetermined Rydberg state so as to induce an Electromagnetic Induced Transparency, EIT, effect; characterised in that: communications from the first wireless transceiver to the second wireless transceiver occur during a first timeslot and communications from the second wireless transceiver to the first wireless transceiver occur during a second timeslot; the first wireless transceiver further comprises a transmitter configured to transmit data to the second wireless transceiver during the first timeslot and further configured to transmit a local oscillator signal during the second timeslot; and the electromagnetic field receiver is configured to receive, at the transmission medium and during the second timeslot, a phase-modulated signal from the second wireless transceiver and the local oscillator signal from the transmitter, wherein a combination of the phase-modulated signal and the local oscillator signal causes a detectable change of the probe signal from which a phase state of the phase-modulated signal can be detected. an electromagnetic field receiver, the electromagnetic field receiver including a first optical transmitter, a second optical transmitter, and a transmission medium, wherein the first optical transmitter is configured to transmit a probe signal via the transmission medium at a probe frequency and the second transmitter is configured to transmit a coupling signal via the transmission medium at a coupling frequency, wherein the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state and the coupling frequency is set to excite electrons of the transmission medium to a predetermined Rydberg state so as to induce an Electromagnetic Induced Transparency, EIT, effect; characterised in that: communications from the first wireless transceiver to the second wireless transceiver occur during a first timeslot and communications from the second wireless transceiver to the first wireless transceiver occur during a second timeslot; the first wireless transceiver further comprises a transmitter configured to transmit data to the second wireless transceiver during the first timeslot and further configured to transmit a local oscillator signal during the second timeslot; and the electromagnetic field receiver is configured to receive, at the transmission medium and during the second timeslot, a phase-modulated signal from the second wireless transceiver and the local oscillator signal from the transmitter, wherein a combination of the phase-modulated signal and the local oscillator signal causes a detectable change of the probe signal from which a phase state of the phase-modulated signal can be detected. communications from the first wireless transceiver to the second wireless transceiver occur during a first timeslot and communications from the second wireless transceiver to the first wireless transceiver occur during a second timeslot; the first wireless transceiver further comprises a transmitter configured to transmit data to the second wireless transceiver during the first timeslot and further configured to transmit a local oscillator signal during the second timeslot; and the electromagnetic field receiver is configured to receive, at the transmission medium and during the second timeslot, a phase-modulated signal from the second wireless transceiver and the local oscillator signal from the transmitter, wherein a combination of the phase-modulated signal and the local oscillator signal causes a detectable change of the probe signal from which a phase state of the phase-modulated signal can be detected.