Method for improving wireless time service precision

A high-precision, wireless technology, applied in the field of improving the accuracy of wireless timing, can solve the problems of accuracy impact, transmission delay jitter, and communication path is difficult to be symmetrical, so as to improve the accuracy, solve the delay jitter, and avoid errors.

Inactive Publication Date: 2010-10-06
上海奇微通讯技术有限公司
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Problems solved by technology

However, in practice, especially in a wireless environment, the communication path is difficult to be symmetrical.
In this case, if IEEE1588 (based on the assumption of symmetric uplink and downlink) is used for master-slave time synchronization, it will inevitably have a great impact on the accuracy
In addition, most of the current wireless systems have link adaptation characteristics, which cause the transmission delay jitter of different frames

Method used

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  • Method for improving wireless time service precision
  • Method for improving wireless time service precision
  • Method for improving wireless time service precision

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Embodiment Construction

[0018] In this embodiment, a DSP processor and IEEE1588 protocol software are used to realize high-precision time synchronization. The DSP processor can drive the wireless network card to realize the wireless timing function, and calculate Δ to compensate the time difference Offset. The clock source of the DSP processor has an external GPS clock source and an internal crystal oscillator (OSC). When performing high-precision wireless time service, select the GPS clock source.

[0019] The steps to calculate the time difference are:

[0020] (1) Record the time t when the master clock sends the Sync message 1 , the time t when the slave clock receives the Sync message 2 , then Delay1+offset=t 2 -t 1 , (I)

[0021] Delay1 is the transmission delay of the forward path; Offset is the time difference between the slave clock and the master clock.

[0022] (2) Record the time t when the slave clock sends the Delay_Req message 3 , the time t when the master clock receives the D...

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Abstract

The invention relates to a method for improving wireless time service precision, which compensates the time difference more accurately and further achieves high-precision wireless time service by calculating the time delay difference of an uplink and a downlink in a wireless environment. The precision can reach an ns level after the time difference is compensated by using the method of the invention. The method of the invention solves the problem of link asymmetry by compensating the time difference, is more suitable for a wireless transmission environment, has universality, and solves the problem of time delay jitter caused by adaptive property of a wireless system link.

Description

technical field [0001] The invention relates to a method for improving wireless timing accuracy, specifically a method for improving wireless timing accuracy by amending IEEE1588 time measurement algorithm and customizing wireless links, and belongs to the technical field of wireless communication. Background technique [0002] The quality of the transmission link in the wireless environment may be very unstable. In addition, due to the use of different frequency bands, or due to the time-varying characteristics of the wireless transmission environment, the transmission delay of the uplink and downlink wireless links may be asymmetrical, thus affecting the uplink and downlink. A time measurement system with symmetry assumptions, such as IEEE1588. The IEEE1588 standard provides a high-precision, low-cost distributed clock synchronization method. The key assumption of the agreement is that the communication path is symmetrical. However, in practice, especially in a wireless e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L7/00H04J3/06H04L12/56
CPCH04J3/0667
Inventor 罗庆霖李卓群夏洪涛
Owner 上海奇微通讯技术有限公司
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