A time synchronization method includes, a boundary device of a third-party network side receives a synchronization packet carrying a time synchronization offset and is delivered by a boundary device of an upstream network side on the basis that boundary devices in an entire network are all boundary clock (BC) devices, where the time synchronization offset is a time offset between a time domain of the upstream network and a time domain of the third-party network, and the boundary device of the third-party network side transparently transmits the synchronization packet carrying the time synchronization offset to a boundary device of a downstream network side such that the boundary device of the downstream network side performs time synchronization with the boundary device of the upstream network side according to the time synchronization offset. Thus time synchronization among multiple time domains in a network.

A system and method for measuring propagation delays and other delays in an optical switching system. A transmitter is connected, through a circuit switch, to a receiver. To measure the propagation delay between the transmitter and the receiver, the transmitter sends one or more time-tagged ranging messages and the receiver calculates a propagation delay from the difference between the time of receipt and the time of transmission. In another embodiment, a time delay between message transmission and transition of a CDR of the receiver to a fast acquisition mode is adjusted, by trial and error, to find a range of such time delays for which transmission is successful. A time delay between the transmitter and the switch is measured by establishing or breaking the connection and determining, for various tentative time delay values, whether transmission succeeds.

A packet processing method includes receiving a first packet by a first receiving interface of a media conversion module of a first network device, where the first packet includes a first alignment marker (AM), sending a second packet by a first sending interface of the media conversion module, where the second packet includes the first AM, and the second packet is the first packet processed by the media conversion module, and calculating a time interval T.sub.1 between a time at which the media conversion module receives the first packet and a time at which the media conversion module sends the second packet, where the T.sub.1 is used to compensate for a first timestamp at which the first network device receives or sends the third packet.

One embodiment includes a system. The system includes a receiver configured to extract a timestamp from a header of each packet of a data stream received from a network and to de-packetize the data stream to provide a stream of data blocks. The timestamp can correspond to generation of each data block associated with each respective packet of the data stream according to a global timebase. The system also includes a delay controller configured to measure a delay associated with each packet of the data stream based on the timestamp relative to the global timebase and to control converting the data stream to a corresponding analog output signal for transmission based on the measured delay.

A delay measuring device of a communication system that includes the delay measuring device sequentially transmitting and receiving frames having a known frame length, and a measurement object device serving as an object for measuring a round trip time by the delay measuring device, includes: an RTT measuring unit to measure a round trip time with respect to the measurement object device a number of times using information for delay measurement in the frame; an RTT change detection unit to detect a change of a value of the round trip time based on the values of the round trip time thus measured; and an RTT determination unit to determine a value of the round trip time to be adopted, from among the values of the round trip time, based on the change of a value of the round trip time.

A terminal device registration method and a device, where the method includes sending upstream registration window information to a terminal device, where the upstream registration window information indicates a starting position of an upstream registration window to the terminal device, receiving an upstream access signal sent by the terminal device from the starting position of the upstream registration window, where the upstream access signal includes a correlation sequence symbol and at least one orthogonal frequency division multiplexing (OFDM) symbol following the correlation sequence symbol, the correlation sequence symbol is constituted by a first sequence that meets a preset condition, and the at least one OFDM symbol modulates access information by means of differential phase modulation in a frequency domain, and performing upstream ranging according to the starting position of the upstream registration window and the correlation sequence symbol.

Embodiments of the present application provide a time synchronization method, UE, base station, device, and computer readable storage medium, wherein the time synchronization method includes receiving indication information, the indication information being used to indicate propagation delay between the UE and a base station and/or time information of a time sensitive network (TSN); determining a time granularity of one bit of the indication information; and performing TSN time synchronization according to the indication information and the time granularity of one bit of the indication information. The present application achieves more accurate time synchronization of a time sensitive network (TSN).

In one embodiment, a local clock is synchronized to a master clock using a Kalman filter to determine state variables using a state transition matrix that includes at least one coefficient that is associated with a digital-to-analog converter (DAC), where the state variables include a unit step variable indicative of a unit step for the system. The local clock is controlled based on the state variables determined using the Kalman filter. The unit step is indicative of an amount by which the frequency of the local clock signal changes in response to a change in the digital input of the DAC.

Techniques for synchronizing a clock of a first apparatus and a clock of a second apparatus in communication with the first apparatus via a network. The techniques include communicating first data between the first apparatus and second apparatus via a network, communicating, while at least a portion of the first data is being communicated via the network, a synchronization packet between the first apparatus and the second apparatus, and communicating second data between the first apparatus and the second apparatus after synchronization between the first apparatus and the second apparatus has been established.

An apparatus for controlling an automated installation has a first controller and a second controller that are connected to one another via a communication network. The first and second controllers each have a local clock and execute control tasks. The first and second controllers each further have a synchronization service that is used to synchronize the respective local clocks to a common reference clock. A timer repeatedly sends a trigger message to the first and second controllers. Each of the two controllers, on receiving the trigger message, determines a local time. The controllers interchange the respective local time and each compute a difference between their own local time and the local time obtained from the other controller. On the basis of the difference, each of the two controllers controls a local actuator.