A communication system and a communication method for one-way transmission are provided. The communication method includes: receiving, by a router, a first synchronization message from a grandmaster clock; generating, by the router, a timestamp according to the first synchronization message; receiving, by the router, at least one data packet; transmitting, by the router, the at least one data packet and the timestamp to a programmable logic device; and outputting, by the programmable logic device, the at least one data packet and the timestamp.

This application provides a method for sending and receiving a clock synchronization packet in FlexE. The method includes: generating, by a sending apparatus, indication information and a plurality of data blocks, where the plurality of data blocks are obtained by encoding a first clock synchronization packet, the indication information is used to indicate a first data block, and the first data block is a data block used for timestamp sampling in the plurality of data blocks; determining, by the sending apparatus, according to the indication information, a moment at which the first data block arrives at a medium dependent interface MDI of the sending apparatus, and generating a sending timestamp, where the sending timestamp is used to record a sending moment of the first clock synchronization packet; generating a second clock synchronization packet carrying the sending timestamp; and sending, by the sending apparatus, the second clock synchronization packet.

A method and system for the post-adjustment (i.e., offline) of event timestamps to implement virtual time synchronization amongst detection node clocks. In existing methodologies with the goal of clock synchronization, clocks (and timestamps generated therefrom) are disciplined or adjusted at the recordation time of the events on a detection node (e.g., a switch/router, an Internet-of-Things (IoT) device, a wireless sensor, etc.). However, there is no particular reason for these clocks or timestamps to be accurate during the recordation time, but rather, should be accurate at their use or interpretation time. Further, through these recordation time adjustments, clock drifts and timing errors may be gradually introduced, leading to runaway inaccuracies. The disclosed method and system intentionally avoids the disciplining of clocks at event recordation times on the detection node and, instead, adjusts timestamps during interpretation times, to overcome the aforementioned issues.

Systems and methods are disclosed herein for syntonizing machines in a network. A coordinator accesses probe records for probes transmitted at different times between pairs of machines in the mesh network. For different pairs of machines, the coordinator estimates the drift between the pair of machines based on the transit times of probes transmitted between the pair of machines as indicated by the probe records. For different loops of at least three machines in the mesh network, the coordinator calculates a loop drift error based on a sum of the estimated drifts between pairs of machines around the loop and adjusts the estimated absolute drifts of the machines based on the loop drift errors. Here, the absolute drift is defined relative to a drift of a reference machine.

A method corrects the time defined by an internal clock of an entity capable of receiving signals from a satellite positioning system and of communicating with at least one other entity. When the signals do not allow the satellite positioning of the entity, the method includes: receiving, by the entity, a message originating from the other entity, the message including a first piece of time data associated with the instant the message was transmitted; determining, by the entity, a second piece of time data associated with the instant the message was received by the entity; calculating a time difference between the second piece of time data and the first piece of time data; and then, when the time difference is negative, determining a time correction to be made to the internal clock of the entity.

The embodiment of the present disclosure provides a time code synchronization method, which includes following steps of: determining a target master node and one or more target slave nodes of a network system among the plurality of nodes; periodically sending a data packet to the one or more target slave nodes by the target master node, wherein the data packet includes a first time code and serial number information of the target master node; compensating the first time code according to the serial number information to obtain a second time code, and synchronizing the second time code by the one or more target slave nodes.

Time stamp replication within wireless networks is described. In an embodiment, a wireless station receives an input time stamp and uses this input time stamp to generate an output time stamp. The wireless station transmits the output time stamp to wireless stations in one of a number of groups which make up the wireless network. The output time stamp is generated to compensate for delays between receiving the input time stamp and transmitting the output time stamp such that output time stamp which is transmitted at a time T corresponds to the value that the input time stamp would have had if it had been received at time T (and not at a time earlier than T). This may, therefore, reduce or eliminate independent time stamp errors and jitter caused by multiple disparate systems and processes.

The present technology relates to a data processing apparatus and a data processing method that enable correct clock synchronization by use of clock information. The data processing apparatus receives a digital broadcast signal so as to process content included in the digital broadcast signal and clock information also included therein for use in presentation synchronization on the content and sends via a transmission path the processed content and clock information to another data processing apparatus that presents the received content. On the other hand, the another data processing apparatus receives via the transmission path the content and clock information sent from the data processing apparatus so as to process presentation synchronization on the received content on the basis of the received clock information. The present technology is applicable to data processing apparatuses configured to process content, for example.

A communication device 2 according to the present disclosure includes (i) a synchronization signal receiver 203 to receive a synchronization signal from a master device 1 that has a reference time and transmits the synchronization signal every synchronization period, (ii) a synchronization signal determiner 210 to determine whether the synchronization signal is normal or abnormal, (iii) a synchronization processor 211 to perform, when the synchronization signal is determined to be normal by the synchronization signal determiner, synchronization processing based on the synchronization signal determined to be normal, and (iv) an additional transmission requester 214 to request the master device to additionally transmit the synchronization signal before transmitting the synchronization signal during a next period when the synchronization signal is determined to be abnormal by the synchronization signal determiner.

A method, at an egress node, includes synchronizing with a global reference time; receiving a signal including a presentation time for when a specific part of the signal is to be transmitted, wherein the presentation time was determined by the ingress node with reference to the global reference time; determining an actual transmission time when the specific part of the signal is transmitted; and causing adjustment of a clock based on a time error derived from a difference between the presentation time and the actual transmission time.