Precision Time Protocol

About: Precision Time Protocol is a research topic. Over the lifetime, 604 publications have been published within this topic receiving 6006 citations. The topic is also known as: PTP & IEEE 1588.

Method and system for synchronization

Abstract: The present invention provides a method for synchronization including: a Synchronous Digital Hierarchy (SDH) device as the slave clock exchanges a Precision Time Protocol (PTP) message utilizing idle bytes in the section overhead of SDH frames with another SDH device as the master clock, calculates the time offset to the SDH device as the master clock, and adjusts the SDH device as the slave clock with the time offset, in order to realize precise time synchronization between SDH devices. The present invention also provides a system for synchronization.

Mobile communication system and mobile communication method capable of respectively compensating delays of in-band time synchronization interface and out-of-band time synchronization interface

Abstract: The invention discloses a mobile communication system and a mobile communication method capable of respectively compensating delays of an in-band time synchronization interface and an out-of-band time synchronization interface. According to the method, a time domain of a main time processing module is adjusted according to an in-band time synchronization adjusting signal and output through the in-band time synchronization interface; a real-time time constant signal time of data (TOD) of the main time processing module is output to the out-of-band time synchronization interface; a 1pulse per second (PPS) signal output interface of the main time processing module is connected to the out-of-band time synchronization interface via a 1588 precision time protocol transceiver; and 1588 precision time protocol transceiver adjusts the delay of a 1PPS signal according to an out-of-band time synchronization adjusting signal and output the 1PPS signal to the out-of-band time synchronization interface. The mobile communication system and the mobile communication method have the advantages that the out-of-band time synchronization interface of packet transport network equipment is isolated from the 1PPS clock signal of the main time synchronization processing module by using the 1588 precision time protocol transceiver, so that the adjustment of delay compensation of the out-of-band time synchronization interface and the in-band time synchronization interface cannot influence each other, thereby improving the precision of synchronization time of base stations.

Efficient unicast signaling in a precision time protocol enabled packet network

Abstract: A first device may provide, to a second device, a first message that includes a first request for a first type of precision time protocol (PTP) message and a second request for a second type of PTP message. The first device may receive, from the second device, a second message based on the first message. The second message may identify whether the first request and the second request are granted. The first device may provide, to the second device, a third message that instructs the second device to provide a first set of messages, associated with the first type of PTP message, and a second set of messages associated with the second type of PTP message. The first device may synchronize a first clock of the first device with a second clock of the second device based on the first set of messages and the second set of messages.

Time correction method

Abstract: PROBLEM TO BE SOLVED: To improve accuracy of time correction in a system assuming a communication apparatus not in accordance with the precision time protocol (PTP).SOLUTION: A method includes calculating a measurement error on the basis of time difference between a minimum round-trip time of a packet between a master device 1 and slave devices 2a and 2b and an actual round-trip transmission time of the packet. Next, it includes obtaining a maximum amount of adjustment on the basis of a record of an amount of adjustment to internal clocks 4b and 4c of the slave devices 2a and 2b. It includes calculating estimation accuracy by multiplying the obtained maximum amount of adjustment by an elapsed time after previous adjustment. It lastly includes comparing the estimation accuracy with the measurement error, and not using the measurement value for time correction of the slave devices 2b and 2c if the measurement error is larger than the estimation accuracy.SELECTED DRAWING: Figure 1

Clock synchronization method and device of communication network

Abstract: The invention discloses a clock synchronization method and a device of a communication network. The method comprises the steps of: a current clock node receives a notification message and other PTP (Precision Time Protocol) protocol messages sent by an upstream clock node; when judging that the current clock node needs to be synchronized with the upstream clock node, extracting a grandfather clock ID in the notification message; and when judging that the grandfather clock ID in the notification message is different from the own clock ID of the current clock node or judging that the grandfather clock ID in the notification message is different from the clock ID recorded by the current clock node, carrying out time synchronization operation according to time information of the other PTP protocol message and time information of the current clock node. The invention has the advantages that the occurrence of a clock loop is effectively prevented, normal synchronization between the clock nodes in the network is ensured, the own strategy is adjusted when the clock loop occurs on the upstream, the synchronization with a clock source with the loop is avoided, the clock deterioration is prevented, and the synchronization quality is improved.