According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency unite each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of slave station devices, and includes a detector that detects each of transmission/reception switching timings between the master station device and each of the radio frequency units, a setter that sets, as reference transmission/reception switching timing, a latest one of the transmission/reception switching timings of the radio frequency unit as candidates of reference transmission/reception switching timing, and a corrector that corrects variation in the transmission/reception switching timings according to the reference transmission/reception switching timing.

Methods, systems, and devices for wireless communications are described that support node connection techniques in wireless systems, such as relay node connections in a wireless backhaul network. A first node, which may be a new node or a node seeking to re-establish a connection, may initiate a connection establishment through transmission of a synchronization signal (SS). The first node, responsive to the SS transmission, may receive a response signal from one of the other nodes, and may establish a link with the other node. In some cases, the response signal may be an SS transmission from the other node, and the first node may transmit a random access request to the other node to initiate establishment of the link. In other cases, the response signal may be a random access request from the other node to initiate establishment of the link.

An embodiment includes a method. The method includes determining, by a first node device in a network, a first master clock according to a first clock data set of the first node device and a first clock data set of another node device in the network, and synchronizing to the first master clock, where the first clock data set includes a first clock domain selection parameter of a node device. The method also includes determining, by the first node device, a second master clock according to a second clock data set of the first node device and a second clock data set of another node device that belongs to a same first node clock domain as the first node device does, and synchronizing to the second master clock, where the second clock data set includes a second clock domain selection parameter of a node device.

According to one embodiment, a communication repeater system includes a master station device, slave station devices, radio frequency units that convert signals from base station systems into optical digital signals for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding slave station device. At least one of the radio frequency units and the master and slave station devices includes a learning-signal input port, and a setter that generates a reference transmission/reception switching timing signal based on a learning signal input to the learning-signal input port and sets the generated signal as reference transmission/reception switching timing. The rest of the units and the devices each include a corrector that corrects variation in transmission/reception switching timing according to the reference transmission/reception switching timing.

According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency unite each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of slave station devices, and includes a detector that detects each of transmission/reception switching timings between the master station device and each of the radio frequency units, a setter that sets, as reference transmission/reception switching timing, a latest one of the transmission/reception switching timings of the radio frequency unit as candidates of reference transmission/reception switching timing, and a corrector that corrects variation in the transmission/reception switching timings according to the reference transmission/reception switching timing.

According to one embodiment, a communication repeater system includes a master station device, slave station devices, and radio frequency units which convert a signal from each base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of the slave station devices. The radio frequency units each include a detector that detects transmission/reception switching timing between the master station device and each of the radio frequency units. The slave station devices each include a setter that sets reference transmission/reception switching timing on the basis of acquired reference time information. The radio frequency units each include a corrector that corrects variation in the transmission/reception switching timing in accordance with the reference transmission/reception switching timing.

Disclosed are devices, systems, apparatuses, methods, products, and other implementations of GNSS repeater systems and methods for improving phase and frequency alignment of RF signals transported through fiber optic communication channels. Acquired RF signals are processed at a remote outdoor unit, where they are digitized, formatted into a CPRI frame, and timestamped. The timestamped CPRI frame is then transported over a fiber optic communication channel to an indoor head end unit. The indoor head end unit extracts timestamp and digitized RF signal from the CPRI frame. The timestamp is then used to synchronize a base transceiver station (BTS) and a precision time protocol (PTP) grand master with the remote outdoor unit.

A method for transmitting time synchronization messages in a communication network between a master clock and a slave clock to be synchronized with the time of the master clock. A network component of the communication network receives the time synchronization messages on one port and sends the time synchronization messages on another port. The network component determines a dwell time of a respective time synchronization message between the receipt and the sending with an internal clock and transmits dwell-time information to the slave clock. The slave clock synchronizes to the master clock using the received time synchronization messages and the associated dwell-time information. In order to perform accurate determination of the dwell-time information in a network component with an internal clock having comparatively low accuracy, the network component suspends all other messages within a time period in which the network component expects to receive a time synchronization message.

A communication apparatus, for relaying a time synchronizing signal between a master and a slave that transmit PTP (Precision Time Protocol) signals, stores a first time of the communication apparatus at a point in time that the communication apparatus receives a first time synchronizing signal addressed to the slave, obtains a second time of the master at a point in time that the first time synchronizing signal is transmitted from the master, from the first time synchronizing signal or the like, obtains an amount of offset that is a difference between a reference time of the master and a reference time of the communication apparatus, using the first time as a time of the slave and the second time as the time of the master in a time synchronizing algorithm of the PTP, and corrects the reference time of the communication apparatus using the amount of offset.