Systems and methods of clock synchronization between devices on a network

A system for synchronizing a first clock and a second clock, the system comprising:

• a communication module configured to transmit across a channel a plurality of packets between a first device with a first clock having a first clock rate and a second device with a second clock having a second clock rate;
• at least one processor configured to:
• obtain a minimum path delay or a mean path delay of the channel;
• obtain a first time when a first sync packet of the plurality of packets is sent from the first device to the second device, the first time being based on the first clock;
• obtain a second time when the first sync packet of the plurality of packets is received by the second device, the second time being based on the second clock;
• obtain a third time when a first response packet from the second device is sent to the first device in response to the first sync packet, the third time being based on the second clock;
• obtain a fourth time when the first response packet from the second device is received by the first device, the fourth time being based on the first clock;
• compute a first path delay across the channel of the first sync packet and the first response packet;
• determine whether the first path delay satisfies a condition involving the minimum path delay or the mean path delay;
• obtain a fifth time when a second sync packet of the plurality of packets is sent from the first device to the second device, the fifth time being based on the first clock;
• obtain a sixth time when the second sync packet of the plurality of packets is received by the second device, the sixth time being based on the second clock;
• obtain a seventh time when a second response packet from the second device is sent to the first device in response to the second sync packet, the seventh time being based on the second clock;
• obtain an eighth time when the second response packet from the second device is received by the first device, the eighth time being based on the first clock;
• compute a second path delay across the channel of the second sync packet and the second response packet;
• determine whether the second path delay satisfies the condition involving the minimum path delay or the mean path delay;
• and
• if at least each of the first path delay and the second path delay satisfies the condition, then:
• compute a first skew between the first time and the fifth time and a second skew between the second time and the sixth time, or compute the first skew between the fourth time and the eighth time and the second skew between the third time and the seventh time;
• and
• compute a ratio based on the first skew and the second skew;
• and
• a rate correction module configured to correct one of the second clock rate of the second clock or the first clock rate of the first clock based on the ratio.

A non-transitory computer readable medium comprising executable instructions, the instructions being executable by a processor to perform a method of synchronizing a first clock having a first clock rate in a first device and a second clock having a second clock rate in a second device, the first device and the second device communicating a plurality of packets across a channel, the method comprising:

• obtaining a minimum path delay or a mean path delay of the channel;
• obtaining a first time when a first sync packet of the plurality of packets is sent from the first device to the second device, the first time being based on the first clock;
• obtaining a second time when the first sync packet of the plurality of packets is received by the second device, the second time being based on the second clock;
• obtaining a third time when a first response packet from the second device is sent to the first device in response to the first sync packet, the third time being based on the second clock;
• obtaining a fourth time when the first response packet from the second device is received by the first device, the fourth time being based on the first clock;
• computing a first path delay across the channel of the first sync packet and the first response packet;
• determining whether the first path delay satisfies a condition involving the minimum path delay or the mean path delay;
• obtaining a fifth time when a second sync packet of the plurality of packets is sent from the first device to the second device, the fifth time being based on the first clock;
• obtaining a sixth time when the second sync packet of the plurality of packets is received by the second device, the sixth time being based on the second clock;
• obtaining a seventh time when a second response packet from the second device is sent to the first device in response to the second sync packet, the seventh time being based on the second clock;
• obtaining an eighth time when the second response packet from the second device is received by the first device, the eighth time being based on the first clock;
• computing a second path delay across the channel of the second sync packet and the second response packet;
• determining whether the second path delay satisfies the condition involving the minimum path delay or the mean path delay;
• and
• if at least each of the first path delay and the second path delay satisfies the condition, then:
• computing a first skew between the first time and the fifth time and a second skew between the second time and the sixth time, or computing the first skew between the fourth time and the eighth time and the second skew between the third time and the seventh time;
• computing a ratio based on the first skew and the second skew;
• and
• correcting one of the second clock rate of the second clock or the first clock rate of the first clock based on the ratio.