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Method and system for performing ranging on optical network unit in passive optical network

A technology of network unit and ranging method, applied in the field of communication, can solve problems such as ONU service interruption and time offset, and achieve the effects of reducing impact, improving uplink transmission efficiency, and protecting time-sensitive services

Inactive Publication Date: 2011-05-25
ZTE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a ranging method and system for an optical network unit in a passive optical network, so as to solve the problem that the ONU service is interrupted due to a large offset in the time when the uplink data sent by the ONU arrives at the OLT

Method used

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  • Method and system for performing ranging on optical network unit in passive optical network
  • Method and system for performing ranging on optical network unit in passive optical network
  • Method and system for performing ranging on optical network unit in passive optical network

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Embodiment 1

[0058] In this embodiment, the OLT is triggered to measure the distance of the ONU in the working state according to the aforementioned condition one: that is, the OLT regularly measures the distance of the ONU in the working state. After triggering the ranging of the ONU that needs to be re-ranging, the OLT measures the ranging of the ONU in the following manner:

[0059] Step 101, the OLT sends a ranging request to the ONU in the working state, and the OLT records the Tarrivaltime assigned to the ONU to send the response ranging information and is expected to arrive at the OLT;

[0060] Step 102, after the ONU receives the ranging request, it replies the sequence number information to the OLT as a response ranging information;

[0061] Step 103, after OLT receives the serial number information of ONU, record the time T0 of the serial number information that ONU sends actually arrives OLT, and calculate the EqD value after this ONU is updated according to following formula: E...

Embodiment 2

[0067] In this embodiment, the OLT is triggered to measure the distance of the ONU in the working state according to the aforementioned condition one: that is, the OLT regularly measures the distance of the ONU in the working state.

[0068] After triggering the ranging of the ONU that needs to be re-ranging, the OLT measures the ranging of the ONU according to the method of step 101 to step 105 in the first example. The difference from the first embodiment is that in this embodiment, the OLT gives the ONU When sending a ranging request, a quiet window needs to be opened for the re-ranging ONU.

[0069] Wherein, the function of opening the quiet window is to be used for the ONU to be ranging to send a response ranging request message, and other ONUs cannot send uplink data in the quiet window. This quiet window can avoid conflicts between the ranging message sent by the ONU to be ranging and the uplink data sent by other ONUs.

[0070] Of course, in other embodiments of the p...

Embodiment 3

[0072] In this embodiment, the OLT is triggered to measure the distance of the ONU in the working state according to the aforementioned condition three: when the upstream data sent by an ONU in the working state does not arrive at the OLT at the time arranged by the OLT, that is, the arrival time of the upstream data sent by the ONU When a certain drift occurs, the OLT calculates the drift value Δt of the arrival time of the ONU uplink transmission data. The OLT defines a drift threshold tl, and when the OLT detects a drift value Δt≥tl of the arrival time of the ONU uplink transmission data, the OLT needs to perform ranging on the ONU.

[0073] In this embodiment, the OLT performs ranging on the ONU in the following manner:

[0074] Step 201, the OLT sends a ranging request to the ONU, and the OLT records the time T1 for sending the ranging request and the start time Tstarttime that the OLT assigns to the ONU for sending the ranging information in response;

[0075] Step 202,...

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Abstract

The invention discloses a method and a system for performing ranging on an optical network unit (ONU) in a passive optical network (PON). The method comprises the following steps that: an optical line terminal (OLT) performs ranging on the ONU in a working state, updates equalization delay (EqD) of the ONU according the ranging result, and sends the updated EqD to the ONU; and the ONU realizes uplink transmission synchronization according to the updated EqD. By adopting the technical scheme, when the ONU, in the working state, of the PON system is required to update the value of the EqD, OLT can perform ranging on the ONU in the working state, so that the influence on the ONU ranging interruption service is reduced, the time-sensitive service of the ONU ranging is protected, and the uplink transmission efficiency of the ONU is improved.

Description

technical field [0001] 本发明涉及通信技术领域,尤其涉及一种无源光网络中光网络单元的测距方法及系统。 Background technique [0002] 吉比特无源光网络(Gigabit-Capable Passive Optical Network,简称为GPON)技术是无源光网络(PON)家族中一个重要的技术分支,与其它PON技术类似,GPON也是一种采用点到多点拓扑结构的无源光接入技术。 [0003] GPON系统的拓扑结构如 figure 1 所示,由局侧的光线路终端(Optical Line Terminal,简称为OLT)、用户侧的光网络单元(Optical Network Unit,简称为ONU)以及光分配网络(Optical Distribution Network,简称为ODN)组成,通常采用点到多点的网络结构。ODN由单模光纤、光分路器、光连接器等无源光器件组成,为OLT和ONU之间的物理连接提供光传输媒质。 [0004] 在GPON系统中,下行方向(由OLT到ONU)的数据传输采用广播方式,每个ONU分别接收所有的帧,再根据ONU-ID(ONU标识)、GEM(GPON Encapsulation Method,GPON封装方法)-Port ID(端口标识)、Allocation-ID(分配标识)来获取属于自己的帧。然而,对于上行方向(从ONU到OLT)的数据传输,由于各个ONU需要共享传输媒质,因此各个ONU应该在OLT安排给自己的时隙内传输上行数据。因各个ONU到OLT之间的距离不同,为防止各个ONU发送的上行数据同时到达OLT,OLT需要对处于注册激活阶段的ONU进行测距。 [0005] 在现有对ONU测距的相关技术中,OLT首先确定自身支持的ONU距离自己的最远距离L。OLT测量L处ONU的环路时延(Round trip delay,简称RTD)的值RTD max ,并根据RTD max 确定所有ONU的最大均衡时延(Equalization Delay,简称EqD)的值Teqd。当一个ONU接入到PON系统中时,ONU上电后进入注册激活阶段,当该ONU进入到注册激活阶段的测距阶段时,OLT对该ONU进行测距,OLT测量该ONU的RTD i ,从而得到该ONU的均衡...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/08H04B10/12
CPCH04Q2011/0079H04Q11/0067H04J3/0682H04J3/0652
Inventor 张伟良耿丹
Owner ZTE CORP
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