A local oscillator synchronization method of pon system and onu and olt

A local oscillator frequency, local technology, applied in the field of communication, can solve problems such as communication failure affecting the bit error rate, and achieve the effect of avoiding overlapping

Active Publication Date: 2011-11-30
ZTE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In a high-speed coherent system, the size of the frequency difference will directly affect the detected bit error rate or even the communication failure.

Method used

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  • A local oscillator synchronization method of pon system and onu and olt
  • A local oscillator synchronization method of pon system and onu and olt
  • A local oscillator synchronization method of pon system and onu and olt

Examples

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Effect test

Embodiment 1

[0052] like figure 1 As shown, the embodiment of the present invention provides a local oscillator synchronization method of a PON system, which is applied in an optical network unit (ONU), and includes the following steps:

[0053] S101: the ONU sends an uplink spread spectrum signal to an optical line terminal (OLT);

[0054] Wherein, there may be one or more ONUs. When there are multiple ONUs, the uplink spread spectrum signals sent by each ONU include different spread spectrum codes.

[0055] The ONU can send the uplink spread spectrum signal with an optical power lower than that in normal communication, which can reduce interference to other on-going channels, thus not affecting normal communication on other on-going channels.

[0056] S102: The ONU receives the downlink spread spectrum signal including the frequency control word sent by the OLT, and demodulates the spread spectrum signal to obtain the frequency control word;

[0057] The frequency control word is a fre...

Embodiment 2

[0097] In a specific application scenario, take a high-speed UDWDM-PON (Ultra-Dense Wavelength Division Multiplexing-Passive Optical Network) system as an example, user 1 transmits data on channel 1, and another user 2 transmits data on channel 1, while another user 2 uses its wavelength when the light source is turned on. If it falls in the adjacent channel 1, it is necessary to pull the center frequency of the user 2 signal to the designated channel 2, so as to ensure that the data communication of the two channels will not interfere with each other. However, the OLT cannot directly extract the signal of user 2 from channel 1. At this time, the transmission data of user 2 can be spread-coded by CDMA technology to obtain a certain coding gain and reduce its transmission optical power to a level far lower than that of user 2. With a power level of 1, user 2 demodulates downlink low bit rate frequency control data while ensuring that the signal transmission of channel 1 is not a...

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Abstract

Disclosed are a local oscillator synchronization method of a passive optical network (PON) system, an optical network unit (ONU) and an optical line termination (OLT). The method is respectively applied in the ONU and the OLT, comprising: the ONU sending an uplink spread spectrum signal to the OLT; the OLT de-spreading the uplink spread spectrum signal and estimating a local oscillator frequency of the ONU; generating a frequency control word according to a frequency offset value between the local oscillator frequency and a channel specified by the OLT; modulating the frequency control word into a downlink spread spectrum signal and sending the signal to the ONU; the ONU demodulating the downlink spread spectrum signal to obtain the frequency control word; and adjusting the local oscillator frequency according to the frequency control word. According to the method, the local oscillator frequency of each ONU is pulled to the channel specified by the OLT, thereby avoiding the overlap of signal spectrum after each ONU is started. Local oscillator synchronization of the PON system is realized without affecting the normal communication of in-transmitting users.

Description

technical field [0001] The invention relates to the communication field, in particular to a local oscillator synchronization method of a passive optical network (PON) system, and an optical line terminal (OLT) and an optical network unit (ONU) for realizing the method. Background technique [0002] Passive Optical Network (PON) is a point-to-multipoint optical fiber access technology, which consists of an optical line terminal (optical line termination, OLT) at the central office, an optical network unit (optical network unit) at the user side unit (ONU for short) and optical distribution network (ODN for short), using single-fiber bidirectional transmission, and there is no active electronic device in the optical distribution network. The transmission of information in the PON adopts the broadcast method for the downlink (OLT transmission), and the uplink (ONU) adopts time-sharing transmission, and the OLT authorizes an ONU to send data. [0003] At present, the access net...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04Q11/00
CPCH04Q2213/1336H04Q11/0067H04Q11/00H04Q2213/1301H04Q2011/0088H04Q2213/13294
Inventor 陈宏伟梁云华陈明华谢世钟何子安苏婕张佩华
Owner ZTE CORP
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