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Time synchronization method and system

A technology for time synchronization and message synchronization, which is applied in time division multiplexing systems, synchronization devices, communication between multiple stations, etc., and can solve message length inconsistencies, adjacent cell interference, master-slave phase deviation, etc. problem, to avoid the effect of phase asymmetry

Active Publication Date: 2011-04-06
ZTE CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The existing IEEE1588-2008 standard does not clearly describe the required lengths of various messages, which may lead to inconsistent lengths of messages sent by different manufacturers, and inconsistent message lengths will cause delay asymmetry problems, resulting in synchronization between the master and slave. There will be a certain phase deviation
When the phase deviation exceeds the protocol requirements, it will cause problems such as unsuccessful cell handover, call drop, and interference between adjacent cells.
[0006] The technical problem to be solved by the present invention proposes a time synchronization method and system to solve the phase misalignment problem caused by inconsistent lengths of event messages when IEEE1588 is used for time synchronization

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Embodiment Construction

[0039] IEEE 1588 is an Ethernet clock synchronization protocol (PTP protocol), which realizes master-slave synchronization through synchronization messages.

[0040] The PTP protocol can be carried on Ethernet 802.3, UDP / IPv4, and UDP / IPv6. The form of the 802.3 frame structure is shown in Table 1, and the data field must be at least 46 bytes. For the PTP message, its content is placed in the Data / Load (data / load) part, so the PTP message must have at least 46 bytes.

[0041] Table 1

[0042]

[0043] In the delayed request response mechanism, use figure 1 The Sync (synchronization), Follow_up (tracking), Delay_Req (delay request) and Delay_Resp (delay response) messages in the figure 1 Among them, t1 and t2 are the sending and receiving timestamps of the Sync message respectively, that is, t1 is the time when the Sync message leaves the master device (Master), and t2 is the time when the Sync message arrives at the slave device (Slave). t3 and t4 are the sending and rec...

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Abstract

The invention discloses a time synchronization method and a time synchronization system. The method comprises that: a slave device constructs a delay request message with the length consistent with that of a synchronous message sent to the slave device by a master device, and sends the delay request message to the master device; and the slave device calculates time deviation between the slave device and the master device according to the sending and receiving time of the synchronous message and the sending and receiving time of the delay request message so as to achieve time synchronization with the master device. By adopting the invention, a problem of phase asymmetry caused by inconsistency of lengths of event messages can be avoided in a delay request response mechanism.

Description

technical field [0001] The present invention relates to the field of clock synchronization, in particular to a time synchronization method and system. Background technique [0002] In the field of 3G wireless communication, there are several wireless standards: CDMA (Code Division Multiple Access, Code Division Multiple Access) 2000, WCDMA (Wideband Code Division Multiple Access, Wideband Code Division Multiple Access), TD-SCDMA (Time Division-Synchronous Code Division Multiple Access (TSCDMA), WIMAX (Worldwide Interoperability for Microwave Access), LTE (Long Time Evolution, TDD / FDD). For systems based on TDD (Time Division Duplex, time division duplex), such as CDMA2000, TD-SCDMA, LTE (TDD), WIMAX, etc., strict phase synchronization is required to ensure smooth completion of cell handover. Based on FDD (Frequency Division Duplex, Frequency Division Duplex) systems, such as GSM (Global System for Mobile Communications, Global System for Mobile Communications), WCDMA, LTE (...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04W56/00H04B7/26
CPCH04J3/0667H04W56/00
Inventor 罗丽傅小明白磊
Owner ZTE CORP