1、INTERNATIONAL TELECOMMUNICATION UN ION ITU-T TELECOMMUNICATION STAN DARD IZATION SECTOR OF ITU G.983.3 (03/2001) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital sections and digital line system - Optical line systems for local and access networks A broadband optical ac
2、cess system with increased service capability by wavelength allocation ITU-T Recommendation G.983.3 (Formerly CCIlT Recommendation) INTERNATIONAL TELECOMMUNICATION UN ION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU G.983.3 (03/200 I ) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTE
3、MS AND NETWORKS Digital sections and digital line system - Optical line systems for local and access networks A broadband optical access system with increased service capabi I ity by wavelength allocation ITU-T Recommendation G.983.3 (Formerly CCITT Recommendation) ITU-T G-SERIES RECOMMENDATIONS TRA
4、NSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS TRANSMISSION SYSTEMS INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE METALLIC LINES COORDINATIO
5、N OF RADIOTELEPHONY AND LINE TELEPHONY TESTING EQUIPMENTS TRANSMISSION MEDIA CHARACTERISTICS DIGITAL TERMINAL EQUIPMENTS DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARlUER- SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WIT
6、H General Parameters for optical fibre cable systems Digital sections at hierarchical bit rates based on a bit rate of 2048 kbi/s Digital line transmission systems on cable at non-hierarchical bit rates Digital line systems provided by FDM transmission bearers Digital line systems Digital section an
7、d digital transmission systems for customer access to ISDN Optical fibre submarine cable systems Access networks - Ix? I ptical line systems for local and access ne$vorks “ocal exchange T152814W3 Figure 4/G.983.3 - Example of OLT functional blocks 5.6 See 5.6/G.983.1. Optical Distribution Network fu
8、nctional block 6 Services Such a high speed access system could provide the complete range of all currently known and new services being discussed for the residential subscribers and business customers. Here transmission systems service independence has to be regarded. 10 ITU-T 6.983.3 (0312001) The
9、se services cover a broad range of network requirements like bit rate, symmetry/asymmetry or delay, and range from video distribution, with varying degrees of interactivity, to electronic data transfer, LAN interconnection, transparent Virtual Paths, and so on. What specific services should be provi
10、ded is clearer to some operators than to others and depends heavily on the particular regulatory conditions of each operators markets, as well as on the own markets potential. How these services are delivered in a cost effective way is a function not only of legal conditions, but also of factors inc
11、luding existing telecommunications infrastructure, dwelling distribution and residential and business customers mix. In spite of this varied market background there are some features which have been perceived as common to all parties. They can be summarized as follows: - some services require bit ra
12、tes higher than those supported by PSTN and basic ISDN. These services are best delivered on fibre-based or fibre hybrid networks; as the services evolve and newer services are introduced, the bandwidth and management requirements will increase. This requires the access network to be flexible and ea
13、sily upgradable; additional services, such as video distribution service overlaid ATM-PON, can be provided in an appropriate manner using the WDM scheme, where necessary. The choice of video modulation type will have an impact on the system requirements, but the video modulation system is beyond the
14、 scope of this Recommendation. - - 7 The location of UNI and SNI is preliminary given in the reference configuration (see Table 1). Other types of services such as video broadcast are for further study. User Network Interface and Service Node Interface Table UG.983.3 - UNI and SNI Service type Defin
15、ed in ITU-T G.982 UNI standard SNI standard ITU-T G.902 ITU-T G.902 - Digital broadband video system - Multimedia services - VPleasedline - ATMSVC 8 Optical network requirements ITU-T G.967.1 m-T 1.432 ITU-T G.967.2 IEEE 802.3 8.1 See 8.UG.983.1. Layered structure of optical network 8.2 The waveleng
16、th of the ATM-PON downstream signal (single fibre system) is in the 1.5 pm band and that of the ATM-PON upstream signal is in the 1.3 pm band in IT-T G.983.1. This Recommendation defines the new wavelength allocation to enable additional new services using the wavelength band defined in ITU-T G.983.
17、1. The ATM-PON downstream wavelength band shall be compressed within the original 1.5 pm band and new wavelength bands shall be assigned for new additional services. Physical medium dependent layer requirements for the wavelength allocation ITU-T G.983.3 (03/2001) 11 Figure 5 and Table 2 define the
18、new wavelength allocation. This reduces the ATM-PON downstream allocation currently defined in IT-T G.983.1 to a portion of the available downstream optical spectrum. This portion for the ATM-PON shall be referred to as the “Basic Band“. An additional wavelength band will then be made available and
19、be referred to as the “Enhancement Band.“ Uses for the Enhancement Band include at least video services and Wavelength Division Multiplexing (WDM) services. A guardband separates the Basic Band from the Enhancement Band. The interference between signals in these two bands causes signal degradation t
20、o each other, which shall be kept negligible. Required isolation between these bands depends on optical power level, modulation scheme and so on. An example of WDM filters is described in Appendix III. The specifications for Future L Band in the 1.5 pm band, and the “Reserved for Allocation by ITU-T
21、“ band in the Intermediate region, are for further study. NOTE - Wavelengths in Enhancement Band may be used not only for downstream but also for upstream signal transmission in the WDM scheme. 1.3 um wavelength band (upstream) 1260 1280 1300 1320 1340 1360 Intermediate wavelength band (upstream and
22、/or Downstream) Guardband. b Guardband should be more than 20 dB in optional cases which are described in Appendix UG.983.1. NOTE 2 - The values on ONU transmitter reflectance for the case that the value of minimum ORL of ODN at point O, and Or should be more than 20 dB in optional cases which are d
23、escribed in Appendix UG.983.1. NOTE 2 - The values on ONU transmitter reflectance for the case that the value of “minimum ORL of ODN at point O, and Or 8.2.6.2 for Spectral characteristics; 8.2.6.3 for Mean launched power; 8.2.6.3.1 8.2.6.4 for Minimum extinction ratio; 8.2.6.6 8.2.6.6.1 for OLT tra
24、nsmitter; and 8.2.6.6.2 for ONU transmitter. Transmitter at Old and o, for Launched optical power without input to the transmitter; for Mask of transmitter eye diagram; 8.3.6.1 Reflections from equipment (ONWOLT) back to the cable plant are specified by the maximum permissible reflectance of equipme
25、nt measured at old/om. It shall be in accordance with Table 4. Maximum reflectance of equipment, measured at transmitter wavelength 8.3.6.2 The specified transmitter performance must be met in the presence at S of the optical reflection level specified in Table 4. Tolerance to the reflected optical
26、power 8.3.7 See the following clauses in ITU-T G.983.1 for each item: 8.2.7.2 8.2.7.3 Optical path between qd/o, and OrdO1u for Minimum optical return loss of the cable plant at point WS, including any connector; and for Maximum discrete reflectance between points S and R. 8.3.7.1 Attenuation range
27、Three classes of attenuation ranges are being specified as defined in ITU-T G.982: - 10-25 dB: Class B; - 15-30 dB: Class C. - 5-20 dB: Class A; ITU-T G.983.3 (03/2001) 19 Attenuation specifications are assumed to be worst-case values including losses due to splices, connectors, optical attenuators
28、(if used) or other passive optical devices, and any additional cable margin to cover allowances for: 1) fture modifications to the cable configuration (additional splices, increased cable lengths, etc.); 2) fibre cable performance variations due to environmental factors; and 3) degradation of any co
29、nnector, optical attenuators (if used) or other passive optical devices between points S and R, when provided. 8.3.7.2 Dispersion Systems considered limited by dispersion have maximum values of dispersion (ps/nm) specified in Table 4. These values are consistent with the maximum optical path penalti
30、es specified. They take into account the specified transmitter type, and the fibre dispersion coefficient over the operating wavelength range. Systems considered limited by attenuation do not have maximum dispersion values specified and are indicated in Table 4 with the entry “NA“ (not applicable).
31、8.3.8 All parameters are specified as follows, and shall be in accordance with Table 4. See the following clauses in ITU-T G.983.1 for each item: 8.2.8.1 for Minimum sensitivity; 8.2.8.2 for Minimum overload; 8.2.8.3 8.2.8.5 8.2.8.6 for Clock extraction capability; 8.2.8.7 for Jitter performance; 8.
32、2.8.7.1 for Jitter transfer; 8.2.8.7.2 for Jitter tolerance; 8.2.8.7.3 for Jitter generation; 8.2.8.8 8.2.8.9 8.2.8.10 Receiver at Ord and 01, for Maximum optical path penalty; for Differential optical path loss; for Consecutive identical digit (CID) immunity; for Tolerance to reflected power; and f
33、or Transmission quality and error performance. 8.3.8.1 Reflections from equipment (ONU/OLT) back to the cable plant are specified by the maximum permissible reflectance of equipment measured at Ord and 01,. It shall be in accordance With Table 4. Maximum reflectance of receiver equipment, measured a
34、t receiver wavelength 8.4 Optical parameters, line code, modulation scheme and so on for the Enhancement Band are out of scope of this Recommendation. However, reflection ffom ONU and OLT may cause signal degradation in the Enhancement Band services. Therefore the Maximum reflectance of equipment me
35、asured at transmitter wavelength and the Maximum reflectance of equipment measured at receiver wavelength for the ONU and the OLT should be specified in the Enhancement Band wavelength. The specification for reflectance of the ONU and OLT are for further study. Physical medium dependent layer requir
36、ements for the Enhancement Band 20 ITU-T G.983.3 (03/2001) 9 See clause 9/G.983.1. Operations Administration and Maintenance (OAM) functionality Applied example OLT Indoor ONU Outdoor ONU (Note 2) 10 Performance See clause 10/G.983.1. Temperature (C) Relative humidity (YO) Normal Short term Normal S
37、hort term Remarks 5to40 O to 50 5 to 85 5 to 90 IEC 60721-3-3 -5 to 45 -45 to 45 - 8 to 100 - ETS 300 019-1-4 (Note 1) (Note 1) class 3k3 class 3k5 - 5 to 95 - IEC 60721-3-3 (Note 3) class 4.1E 11 Environmental condition For the OLT and indoor ONU, the conditions of IEC 6072 1-3-3 are recommended. F
38、or the outdoor ONU, the conditions of IEC 60721-3-4, with the expanded environmental range (4.1E) specified in ETS 300 019-1-4, are recommended. The conditions of IEC 6080 1-2 and 60801 -3 for electro magnetic compatibility are recommended. Examples of the applied environmental conditions for the OL
39、T and ONU temperature and relative humidity are described in Table 5. The other environmental conditions such as environmental pollutants and chemicals are for further study. 12 Safety Safety is defined in -T G.983.1. ITU-T G.9833 (03/2001) 21 APPENDIX I Items Optical interface parameters examples f
40、or ODN unit Specifications 1.1 Introduction Tentative optical parameters for ODN are described below (see Table 4) and are given in this Appendix I as examples for implementation. If appropriate parameters are approved and entered into Table 4, this Appendix will be removed. Mean launched power MIN
41、Mean launched power MAX 1.2 Examples Specified numerical values described in the following table indicate tentative values for items described in Table 4. dBm -7.5 -2.5 -0.5 dBm -3 +2 +4 ODN Class Minimum sensitivity Minimum overload ClassA CIassB ClassC dBm -28.5 -28.5 -3 1.5 dBm -8 -8 -1 1 Items u
42、nit Specifications ONU Receiver (optical interface Ora) ODN Class ClassA Mean launched power MIN dBm -5.5 Mean launched power MAX dBm -1 ClassB ClassC -0.5 -0.5 +4 +4 Minimum overload I dBm I -6 I -6 I -11 ODN Class ClassA Minimum sensitivity dBm -26.5 22 ClassB ClassC -26.5 -31.5 ITU-T G.983.3 (03/2001)
