Method and system for determining a round-trip latency of a quantum communication channel

A quantum communication system for determining a round-trip latency between a first and a second location of a communication channel, comprising:

• a first electronic device that is positioned at the first location comprising a controller and a signal circuit;
• a second electronic device that is positioned at the second location that is remote from the first location comprising a controller and a signal circuit,
• a clock unit that is configured to generate clock cycles which are sent to the first and second electronic device,
• wherein the controller of the first electronic device is configured to:
• set an estimated round-trip latency value by the first electronic device, wherein the estimated round-trip latency value is represented as a binary number and represents a latency measured in clock cycles of the clock unit;
• generate and sending, during a first period, a first test signal by the first electronic device to the second electronic device, wherein the first test signal comprises alternating first values and second values, wherein first and second values are sent at each clock cycle of the clock unit;
• save by the first electronic device each first and second value of the first test signal for at least a duration that corresponds to the estimated round-trip latency value;
• receive a validating signal at the first electronic device;
• compare the validating signal with the first test signal sent during the first period;
• and
• determine if the estimated round-trip latency value is correct based on the comparing of the validating signal and the first test signal,
• wherein the controller of the second electronic device is configured to:
• receive the first test signal at the second electronic device;
• and
• send, to the first electronic device, upon receiving the first test signal, a validating signal that is generated by the second electronic device and is based on the first test signal, wherein the validating signal comprises at least second values when second values from the first test signal are received.

A non-transitory computer readable medium having instructions which when executed by a quantum communication system execute a method for determining a round-trip latency of a communication channel in a quantum communication system between a first device located at a first location and a second device located at a second location that is remote from the first location, wherein the communication system comprises a clock unit configured to generate clock cycles, comprising:

• setting an estimated round-trip latency value by the first device, wherein the estimated round-trip latency value is represented as a binary number and represents a latency measured in clock cycles of the clock unit;
• generating and sending, during a first period, a first test signal by the first device to the second device, wherein the first test signal comprises alternating first values and second values, wherein first and second values are sent at each clock cycle of the clock unit;
• saving by the first device each first and second value of the first test signal for at least a duration that corresponds to the estimated round-trip latency value,
• receiving the first test signal at the second device;
• sending, by the second device to the first device, upon receiving the first test signal, a validating signal that is generated by the second device and is based on the first test signal, wherein the validating signal comprises at least second values when second values from the first test signal are received;
• receiving the validating signal at the first device;
• comparing the validating signal with the first test signal sent during the first period;
• and
• determining if the estimated round-trip latency value is correct based on the comparing of the validating signal and the first test signal.