To solve the problem of still being able to use an inexpensive network controller which can store only a single transmission time, even when telegrams from a plurality of application modules need to be sent in synchronized fashion and the transmission times thereof need to be reliably ascertained and reliably associated with the respective telegrams, provided is a communication device for the synchronized sending of telegrams, a communication system including such a communication device, and a method for the synchronized sending of telegrams. The communication device comprises a coordination device.

The present invention provides a method for time synchronizing one or more devices in a control network using a first device. The method comprises selecting a first device from information of the topology of the control network. The method further comprises sending a first set of packets to the second device, receiving a first set of delay requests in response to the first set of packets, and sending a first set of delay responses in response to the first set of delay requests. The method further comprises, determining a first set of forward times and first set of backward times. The method further comprises, determining a first minimum forward time and a first minimum backward time. Further the method comprises determining a first correction factor. The method also comprises, applying the first correction factor to a clock provided at the second device and storing the first correction factor.

There are provided a clock node, a controller, a method of operating the clock node and a method of operating the controller in a time distribution network (TDN) comprising the controller being in data communication with the clock nodes via a control path. The method of operating the clock node comprises: sending, from the clock node via the control path to the controller, a first timestamp-related data; receiving, by the clock node via the control path from the controller, clock-recovery control data generated by the controller using the first timestamp-related data received from the clock node; processing the received clock-recovery control data to extract data usable for phase and frequency recovery; and using the extracted data to steer frequency and phase characterizing the clock node.

This disclosure presents distributed and decentralized synchronization for wireless transceivers. The disclosed system, device, and method achieve sub-nanosecond synchronization using low-cost commercial off the shelf software defined radios. By providing a decentralized mechanism that does not rely on a hierarchical master-slave structure, networks constructed as disclosed are robust to sensor drop-out in contested or harsh environments. Such networks may be used to create phased array radars and communication systems without requiring wired connections to distribute a common clock or local oscillator reference.

A technique of transporting a time protocol message for time-sensitive networking, TSN, from a first station (910) to a second station (920) through a wireless network (900) including at least one radio device wirelessly connected to at least one base station (400) of the wireless network (900) is provided. As to a method aspect, a method performed by at least one or each of the at least one radio device comprises a step of transmitting to the wireless network (900) a radio device request message requesting establishment of a packet data unit, PDU, session between the radio device and the wireless network (900), the radio device request message being indicative of a time protocol of the time protocol message. The method further comprises at least one of the steps of receiving from and transmitting to the at least one base station (400) of the wireless network (900) the time protocol message according to a Quality of Service, QoS, flow for transporting the time protocol message in the wireless network (900). The QoS flow is unambiguously or uniquely associated with at least one of the PDU session and the time protocol.

A method (1200) by a network node (160, 160c) includes determining (1202) a plurality of Time Sensitive Communication, TSC, or Time Sensitive Networking, TSN, domains (12) that exist in a network. The network node instantiates (1204) at least one virtual bridge (14), wherein each virtual bridge serves at least one TSC and/or TSN domain.

A method performed by a first fronthaul network unit (RU1, RU2,..., RUm) for synchronizing with a second fronthaul network unit (GM; DU1, DU2,..., DUn) across a fronthaul network (100) carrying TDD radio transmissions through obtaining control information indicating UL and DL time periods of TDD radio transmissions and local timing information in a first fronthaul network unit and determining: a first set of synchronization messages transferred between the units within determined fronthaul DL and UL intervals during which there are no TDD transmissions, and a second set of synchronization messages transferred outside of the determined intervals, and synchronizing, based on the synchronization messages, depending on which set the synchronization message belongs to.

A method for securing the time synchronization of an Ethernet on-board network of a motor vehicle, by: determining a delay time of a first signal on a first connecting path between a first control unit of the network and a second control unit of the network; determining a maximum speed of the first connecting path on the basis of the delay time; and determining a type of a transmission medium of the first connecting path on the basis of the maximum speed. The determination of the delay time of a first signal, the determination of the maximum speed of the first connecting path, and the determination of the type of a transmission medium of the first connecting path result in an entropy source being formed that is used to ascertain at least one dynamic key for the connecting path to encrypt a time synchronization message for the connecting path.

This application provides a communication method and a communications device. The method includes: obtaining, by a first communications device, authorization information, where the authorization information indicates that a second communications device is a device that needs to perform time synchronization; and providing, by the first communications device, time information for the second communications device based on the authorization information; or obtaining, by the first communications device, authorization information, where the authorization information indicates that the second communications device is not a device that needs to perform time synchronization; and skipping, by the first communications device, providing time information for the second communications device based on the authorization information, to avoid broadcasting the time information to all communications devices, so that a time synchronization service can be provided for a specific communications device.

This disclosure describes techniques for providing customer isolation of time synchronization traffic using virtualization. For example, a method includes receiving, by a computing device, an Internet protocol (IP) address of a customer network of a plurality of customer networks connected to a cloud exchange executed by the computing device; configuring, by the computing device, a time synchronization server connected to the cloud exchange with a Virtualized Local Area Network (VLAN) associated with the IP address of the customer network, the time synchronization server comprising a plurality of instances that provide a time synchronization service; and configuring, by the computing device, the time synchronization server with a Virtual Routing and Forwarding (VRF) or network namespace for the VLAN, wherein the VRF or network namespace includes a route to send time synchronization traffic between the customer network and a particular instance of the plurality of instances that provide the time synchronization service.