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YD/T 3621 consists of the following parts under the general title Nx25Gbit/s WDM-PON for 5G mobile fronthaul.
—— Part 1: General requirements.
—— Part 2: PMD requirements.
—— Part 3: Management requirements.
This part is Part 2 of YD/T 3621.
This part is developed in accordance with the rules given in GB/T 1.1- 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This part was proposed by and is under the jurisdiction of China Communications Standards Association.
Nx25Gbit/s WDM-PON for 5G mobile fronthaul - Part 2: PMD requirements
1 Scope
This part specifies the physical layer, transceiver index and performance index requirements of the wavelength routing-based N×25Gbit/s WDM-PON system facing the load-bearing requirements of 5G mobile fronthaul network.
This part is applicable to the wavelength routing-based N×25Gbit/s WDM-PON equipment under the environment of public telecommunication network. It may be used as reference for the private telecommunication network.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 9771.1 Single-mode optical fibres for telecommunication - Part 1: Characteristics of a dispersion unshifted single-mode optical fibre
IEEE 802.3cc-2017 IEEE Standard for Ethernet - Amendment 11: Physical Layer and Management Parameters for Serial 25 Gbit/s Ethernet Operation Over Single-Mode Fiber
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
wavelength channel
unidirectional optical communication channel of the only or a group of center frequencies mapped to one branch port of AAWG
3.2
channel spacing
in a given reference grid, the absolute difference between the nominal frequencies of two adjacent wavelength channels
3.3
extinction ratio (ER)
for the digital on-off keying signal generated by the optical transmitter, the extinction ratio is the ratio of the average optical power of the high-level binary digital center point to the average optical power of the low-level binary digital center point
3.4
fibre distance
the total length of the fibre between the reference points R/S and S/R-CG (where applicable, the fiber includes the equivalent fiber representing the introduction of the delay component)
3.5
mask of transmitter eye diagram
a general method of characterizing a transmitter pulse waveform, which includes a specification of each of the following indexes to ensure the appropriate coordination between the transmitter and the receiver, the indexes include rise time, fall time, positive/negative pulse, ringing and jitter. At the appropriate reference points (S/R-CG for downlink, R/S for uplink), the transmitter eye diagram shall meet the requirements of transmitter mask
3.6
mean launch optical power
the single wavelength channel optical power at the corresponding reference point, representing the mean optical power in the characteristics of the optical transmitter. Wherein the optical signal transmitted to the fibre carries a given digital sequence. When expressing the range, the minimum mean launch optical power provides the power level that the transmitter shall always maintain, and the maximum mean launch optical power provides the power level that the transmitter shall never exceed
3.7
central frequency
a specified frequency of a wavelength channel
3.8
optical path loss
optical power loss caused by optical signals transmitting in ODN. Losses are caused by the following factors, including fibres, connectors, splices, dividers, wavelength couplers, attenuation, and other passive optical devices. ODN optical path loss in this part is the loss in any direction between reference point S/R-CG and reference point R/S
3.9
optical return loss (ORL)
the total reflectance value at the source reference point of the optical signal transmission path, measured by the ratio of the transmitted optical power to the reflected optical power
3.10
overload
a receiver parameter equivalent to the maximum average received optical power when a specified BER reference level is generated. Although the single wavelength channel optical power is measured based on the worst scene signal at the appropriate reference point (S/R-CG for uplink direction, R/S for downlink direction), it does not include optical path impairment
3.11
reflectance
the ratio of the reflected optical power to the incident optical power existing at a discrete reflection point
3.12
sensitivity
a receiver parameter equivalent to the minimum average received optical power when a specified BER reference level is generated. Although the above-mentioned single wavelength channel optical power is measured based on the worst scene signal at the appropriate reference point (S/R-CG for uplink direction, R/S for downlink direction), it does not include optical path impairment
3.13
tuning time
the time difference between the moment at which a tunable device deviates from its source wavelength channel and the moment at which it reaches the target wavelength channel
4 Abbreviations
For the purposes of this document, the following abbreviations apply.
ODN of Nx25Gbit/s WDM-PON for 5G mobile fronthaul adopts a point-to-multipoint network structure and consists of passive optical devices such as single-mode fibre, athermal arrayed waveguide grating (AAWG), and optical connector, providing optical transmission medium for physical connection between OLT and ONU, and realizing wavelength routing function between main fibre and branch fibre. The N×25Gbit/s WDM-PON system provides the ONU connected with each branch port (connecting with branch fibre) with a corresponding fixed working wavelength through AAWG in ODN (i.e., the ONU working wavelength is determined by its physical connection with the branch port of AAWG). The reference configuration of N×25Gbit/s WDM-PON system is shown in Figure 1.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Abbreviations 5 ODN configuration of N×25Gbit/s WDM-PON system 6 Physical media dependent (PMD) layer requirements for N×25Gbit/s WDM-PON 6.1 Line rate 6.2 FEC coding 6.3 Physical media and transmission mode 6.4 Line code 6.5 Working wavelength 6.6 Physical media dependent parameters 6.7 Requirements of transmitter at reference point S
ICS 33.040.50 M42 中华人民共和国通信行业标准 YD/T 3621.2—2019 面向5G前传的N×25Gbit/s波分复用无源 光网络(WDM-PON)第2部分：PMD Nx25Gbit/s WDM-PON for 5G mobile fronthaul-Part2：PMD requirements 2019-12-24发布 2019-12-24实施 中华人民共和国工业和信息化部 发布 前言 YD/T 3621《面向5G前传的N×25Gbit/s波分复用无源光网络(WDM-PON)》分为以下部分。 —第1部分：总体。 —第2部分：PMD。 —第3部分：管理层要求。 本部分为YD/T 3621的第2部分。 本部分按照GB/T 1.1—2009给出的规则起草。 请注意本文件的某些内容可能涉及专利。本文件的发布机构不承担识别这些专利的责任。 本部分由中国通信标准化协会提出并归口。 面向5G前传的N×25Gbit/s波分复用无源光网络(WDM-PON) 第2部分：PMD 1 范围 本部分规定了面向5G前传网络承载需求的基于波长路由的N×25Gbit/s WDM-PON系统的物理层、收发器指标以及性能指标要求。 本部分适用于公众电信网环境下的基于波长路由的N×25Gbit/s WDM-PON设备，专用电信网也可参照使用。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 9771.1通信用单模光纤 第1部分：非色散位移单模光纤特性 IEEE 802.3cc-2017-IEEE以太网标准-增补11：基于单模光纤的25Gbit/s以太网的物理层和管理参数(IEEE Standard for Ethernet-Amendment 11：Physical Layer and Management Parameters for Serial 25 Gbit/s Ethernet Operation Over Single-Mode Fiber) 3术语和定义 下列术语和定义适用于本文件。 3.1 波长通道Wavelength Channel 映射到AAWG一个支路端口的唯一或者一组中心频率的单向光通信通道。 3.2 通道间隔Channel Spacing 在给定的参考栅格中，两个相邻波长通道的标称频率绝对差值。 3.3 消光比Extinction Ratio(ER) 对于光发射机产生的数字开关键控信号来说，消光比为高电平二进制数字中心点平均光功率与低电平二进制数字中心点平均光功率之比。 3.4 光纤距离Fibre Distance R/S与S/R-CG参考点之间的光纤(如果适用的话，此处光纤包括代表引入延迟部件的等效光纤)总长度。 3.5 发射眼图模版Mask of Transmitter eye Diagram 一种发射机脉冲波形特性描述的通用方法包括以下各个指标的规格说明来确保其与接收机之间有合适的配合，上述指标包含上升时间、下降时间、正脉冲/负脉冲、振铃和抖动。在适当的参考点(下行为S/R-CG，上行为R/S)处，发射机眼图应符合发射机模版要求。 3.6 平均发射光功率Mean Launch Optical Power 在对应参考点处的单波长通道光功率，表征光发射机特征中的平均光功率。其中，向光纤发射的光信号携带给定的数字序列。当表示范围时，最小平均发射光功率提供了发射机应该一直保持的功率水平，最大平均发射光功率提供了发射机永远不应超过的功率水平。 3.7 中心频率Central Frequency 一个波长通道的规定频率。 3.8 光路径损耗Optical Path Loss 光信号在ODN中传播时产生的光功率损耗。损耗由以下因素导致，包括光纤、连接器、接头、分隔器、波长耦合器、衰减以及其他无源光器件。本部分中ODN光路径损耗是介于参考点S/R-CG与参考点R/S之间任一方向的损耗。 3.9 光回波损耗Optical Return Loss(ORL) 在光信号传播路径的源参考点处的总反射值，用传输光功率与反射光功率的比值来度量。 3.10 过载Overload 一种等效于当产生指定的BER参考水平时的最大平均接收光功率的接收机参数，虽然单波长通道光功率测量取自适当的参考点(S/R-CG上行方向，R/S下行方向)处的最差场景信号，但不包括光路径损伤。 3.11 反射Reflectance 某离散反射点上存在的反射光功率与入射光功率之间的比值。 3.12 灵敏度Sensitivity 一种等效于当产生指定的BER参考水平时的最小平均接收光功率的接收机参数，虽然上述提及的单波长通道光功率测量取自适当的参考点(S/R-CG上行方向，R/S下行方向)处的最差场景信号，但不包括光路损伤。 3.13 调谐时间Tuning Time 可调谐器件偏离其源波长通道时刻至到达目标波长通道时刻之差。 4缩略语 下列缩略语适用于本文件。 AAWG Athermal Arrayed Waveguide Grating 无热阵列波导光栅 BER Bit Error Rate 比特差错率 CT Channel Terminal 通道终端 FEC Forward Error Correction 前向纠错 NRZ Non Return Zero 非归零码 OA Optical Amplifier 光放大器 ODN Optical Distribution Network 光分配网络 OLT Optical Line Terminal 光线路终端 ONU Optical Network Unit 光网络单元 ORL Optical Return Loss 光回波损耗 PMD Physical Medium Dependent 物理媒质相关 PON Passive Optical Network 无源光网络 SNI Service Network Interface 业务网络接口 UNI User Network Interface 用户网络接口 WDM Wavelength Division Multiplexing 波分复用 WDM-PON Wavelength Division Multiplexing-Passive Optical Network 波分复用无源光网络 WM Wavelength Multiplexer 波长复用器 5 N×25Gbit/s WDM-PON系统ODN配置 面向5G前传的N×25Gbit/s WDM-PON的ODN采用点到多点的网络结构，由单模光纤、无热阵列波导光栅(简称AAWG)和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，并实现主干光纤和分支光纤之间的波长路由功能。N×25Gbit/s WDM-PON系统通过ODN中AAWG为各分支端口(连接分支光纤)所连接的ONU提供对应固定的工作波长(即ONU工作波长是由其和AAWG的分支端口的物理连接决定)。N×25Gbit/s WDM-PON的系统参考配置如图1所示。
