Huawei Technologies Co., Limited

Future Wei Technologies, Inc.

Guijin Xu

Guozhu Long

Ruzhou Feng

Jianhua Liu

Dong Wei

Ruijie Xiao

Xuyong Wu

Yuchen Jia

Zhilei Zhao

Anni Wu

Ming Huang

The present invention provides a method, an apparatus, and a system for time synchronization of an xDSL. The method includes: transmitting, by a customer premises equipment, a first symbol to a central office equipment, and obtaining time Tsindicating the moment that the first symbol is transmitted; receiving, by the CPE, a second symbol transmitted by the CO, and obtaining time Tsindicating the moment that the second symbol is received; obtaining, by the CPE obtains time Tmindicating the moment that the first symbol is received by the CO and time Tmindicating the moment that the second symbol is transmitted by the CO; the CPE calculates an offset between a clock of the CPE and a clock of the CO according to Ts, Ts, Tmand Tm; and the CPE adjusts the clock of the CPE according to the offset to achieve synchronization.

Method, apparatus, and system for time synchronization of XDSL

An apparatus comprising a customer node configured to couple to an access node and to receive via a channel from the access node a time of day (TOD) value and a corresponding sample index (SNUM) value, wherein the TOD value and the SNUM value are used to estimate a second time of day (TOD') value based on a propagation delay of the channel (L-Delay), and wherein the TOD value and the TOD&#x2032; value are used to estimate a second SNUM value (SNUM&#x2032;) based on L-Delay and a plurality of parameters.

Method for accurate distribution of time to a receiver node in an access network

A method, apparatus, and system for time synchronization are disclosed. The method comprising: obtaining a master sending time stamp, a slave receiving time stamp, a slave sending time stamp, and a master receiving time stamp; and adjusting the time of the slave clock according to the offset calculated from the time stamps to synchronize with the clock time of the master clock. With the present invention, in passband transmission systems that transmit signals continuously in units of symbols, the time synchronization is implemented between the master clock and the slave clock.

Method, apparatus, and system for time synchronization

A clock synchronization method, customer premises equipment and a clock synchronization system are provided. The customer premises equipment reads a first time stamp when receiving a first specific position of a first DMT signal sent by central office equipment; reads a second time stamp when sending a second specific position of a second DMT signal; receives a third time stamp and a fourth time stamp that are sent by the central office equipment through a data information channel. The third time stamp is read when the central office equipment sends the first specific position of the first DMT signal, and the fourth time stamp is read when the central office equipment receives the second specific position of the second DMT signal. The customer premises equipment adjusts a clock of the customer premises equipment according to the first, second, third and fourth time stamps.

Clock synchronization method, customer premises equipment and clock synchronization system

A clock synchronization method, apparatus, and system are provided according to the embodiments of the present invention. The method includes: receiving time information TMfrom a central office side, in which the time information TMis obtained by the central office side by reading a local clock of the central office side when transmission data at a first designated location starts to be transferred, and the local clock of the central office side is synchronous with a Global Positioning System (GPS) clock or a Building Integrated Timing Supply (BITS) clock; determining whether transmission data at a second designated location starts to be received, if so, reading a local clock of the Customer Premises Equipment side to obtain time information TS; and synchronizing a clock frequency of the Customer Premises Equipment side to the central office side according to the time information TMand the time information TS

Clock synchronization method, apparatus, and system

The present invention provides a method, an apparatus, and a system for time synchronization of an xDigital Subscriber Line (xDSL). The method includes: transmitting, by a customer premises equipment (CPE), a first symbol to a central office (CO) equipment, and obtaining time Tsindicating the moment that the first symbol is transmitted; receiving, by the CPE, a second symbol transmitted by the CO, and obtaining time Tsindicating the moment that the second symbol is received; obtaining, by the CPE obtains time Tmindicating the moment that the first symbol is received by the CO and time Tmindicating the moment that the second symbol is transmitted by the CO; the CPE calculates an offset between a clock of the CPE and a clock of the CO according to Ts, Ts, Tm, Tmand a delay of the CPE; and the CPE adjusts the clock of the CPE according to the offset to achieve synchronization. According to the present invention, by adjusting the time of the clock of the CPE and the time of the clock of the CO, the offset between the clock of the CPE and the clock of the CO can be obtained accurately to effectively achieve time synchronization between the CPE and the CO.

The present invention provides two subscriber line testing systems, three broadband/narrowband telecommunication systems and a broadband line card. In the subscriber line testing systems of the present invention, a test module is configured in the CO broadband device, reducing the complexity and the cost of the subscriber line testing systems. In the broadband line card provided by the present invention, line capturing relays are configured in the broadband line card so that the LPF card can be designed as a passive device to reduce corresponding costs, thus using this broadband line card helps reduce the complexity of the CO broadband device and the subscriber cost thereof. In the three broadband/narrowband telecommunication systems provided by the present invention, by using the subscriber line testing systems and the broadband line card, the complexity of broadband/narrowband telecommunication systems and subscriber cost thereof are also reduced. In the third broadband/narrowband telecommunication system provided by the present invention, both the broadband line card without line capturing relay and the broadband line card with line capturing relay can be incorporated so that a better compatibility is provided.

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Shenzhen, China

Guijin Xu