A communication system comprises a clock generator configured to generate a plurality of system clock signals used to synchronize components included in each of communication nodes in the communication system based on an external clock signal provided by an external clock source located outside the communication system and a physical layer configured to transmit any one of the generated system clock signals to a small cell communicatively connected to an end communication node of the communication system.

A method is described for providing a universal time in a control unit. The universal time is generated by a timer of the control unit or is received via a communication link from at least one external unit, the universal time being transmitted directly or as at least two time stamps to at least one component for ascertaining time deviations. Furthermore, a control unit, a computer program and a machine-readable storage medium are also described.

A system is described for maintaining synchrony of operations among a plurality of devices that have independent clocking arrangements. The system includes a task distribution device that distributes tasks to a synchrony group comprising a plurality of devices that are to perform the tasks distributed by the task distribution device in synchrony. The task distribution device distributes each task to the members of the synchrony group over a network. Each task is associated with a time stamp that indicates a time, relative to a clock maintained by the task distribution device, at which the members of the synchrony group are to execute the task. Each member of the synchrony group periodically obtains from the task distribution device an indication of the current time indicated by its clock, determines a time differential between the task distribution device's clock and its respective clock and determines therefrom a time at which, according to its respective clock, the time stamp indicates that it is to execute the task.

A method of synchronization of a communication device comprising a first and second communication ports, each of the first and second communication port being associated with a respective first and second time system, the method comprising a regular master synchronization process synchronizing regularly the first time system with an external synchronization server according to a time synchronization protocol; a regular slave synchronization process synchronizing regularly the second time system with the first-time system; detecting a loss of synchronization between the first and second time system; determining which of the first and second time system is desynchronized; and synchronizing the desynchronized time system with the other one.

[Problem] It is possible to improve the quality of time information by suppressing a jump in time which arises when switching a transfer path in a BC apparatus to which transfer paths of time information of at least 2 systems are connected to an input side. [Solution] A time synchronization apparatus 20 is mounted on a BC apparatus 12c in which two systems of at least a 0-system route (0-system) and a 1-system route (1-system) are connected to an input side, and includes a time correction value holding unit 26 configured to hold a 0-system correction value in which a time error resulting from delay of UTC due to performance inherent to the BC apparatus is the same value as a time error accumulated on the 0-system side and a 1-system correction value in which the time error is the same value as a time error accumulated on the 1-system side. Further, a failure restoration detection unit 23 configured to detect a failure in the 0-system or the 1-system, a time calculation unit 24 configured to perform correction by subtracting a 1-system correction value relating to a normal 1-system from UTC having time error accumulated on the normal 1-system side, when a failure in the 0-system is detected, and a path switching unit 25 configured to switch to the normal 1-system side such that the UTC after correction is transferred, when the failure is detected, are included.

A system and method for transmitting packets from a transceiver to a repeater in the presence of relative motion between the transceiver and the repeater. In some embodiments, the method includes: adjusting a plurality of transmission times; transmitting each of a plurality of packets, at a respective adjusted transmission time, from the transceiver to the repeater; and retransmitting, by the repeater, each of the packets, at a respective retransmission time, each of the retransmission times being, as a result of the adjusting, more nearly the same as it would have been, in the absence of: the relative motion, and the adjusting.

Continuance in quality level of an input timing signal may be provided. Clock source reference timing information may be receive by a first node from a second node as an input. The first node may be downstream from the second node. Then the first node may receive an event message associated with a future event associated with the second node. The first node may then refrain, for a period of time in response to receiving the event message, from switching the input for clock source reference timing information to a source other than the second node.

A radio base station is disclosed including a first communication device that supports a cell; and a second communication device that is connected to the first communication device and controls the first communication device, wherein the second communication device transmits a radio resource control message including a reference system frame number and a reference time associated with the reference system frame number, to a terminal through the first communication device, and the first communication device transmits an acknowledgment to the transmission of the radio resource control message, to the second communication device. In other aspects, a radio communication method and a radio communication system are also disclosed.

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.

Aspects of the present disclosure describe a system and method for synchronizing time, frequency, and phase among a plurality of devices.