1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Series L TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 22 (04/2016) SERIES L: ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEM
2、ENTS OF OUTSIDE PLANT ITU-T L.1700 Low-cost sustainable telecommunication for rural communications in developing countries using fibre optic cable ITU-T L-series Recommendations Supplement 22 ITU-T L-SERIES RECOMMENDATIONS ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTIO
3、N, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT OPTICAL FIBRE CABLES Cable structure and characteristics L.100L.124 Cable evaluation L.125L.149 Guidance and installation technique L.150L.199 OPTICAL INFRASTRUCTURES Infrastructure including node element (except cables) L.
4、200L.249 General aspects and network design L.250L.299 MAINTENANCE AND OPERATION Optical fibre cable maintenance L.300L.329 Infrastructure maintenance L.330L.349 Operation support and infrastructure management L.350L.379 Disaster management L.380L.399 PASSIVE OPTICAL DEVICES L.400L.429 MARINIZED TER
5、RESTRIAL CABLES L.430L.449 For further details, please refer to the list of ITU-T Recommendations. L series Supplement 22 (04/2016) i Supplement 22 to ITU-T L-series Recommendations ITU-T L.1700 Low-cost sustainable telecommunication for rural communications in developing countries using fibre optic
6、 cable Summary Supplement 22 to ITU-T L-series Recommendations identifies a low-cost, sustainable optical cable solution for potential users of broadband digital services in remote or rural areas who are unlikely to have such services. This solution would quickly and inclusively close the digital di
7、vide which is a key target of the ITU Connect 2020 Agenda. Mature and proven technologies are best integrated into affordable and reliable solutions suitable for local, non-skilled people to install, operate, maintain and repair so that the system will become part of their community, thus leading to
8、 better system maintenance and quicker damage recovery. Best practice examples use lightweight, thin and robust optical cables and commodity-type media converters. The results of field trials are presented in this Supplement. The cost of such cables, with their simple construction, is estimated to b
9、e one tenth that of using conventional optical cables. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L Suppl. 22 2016-04-27 5 11.1002/1000/12964 Keywords Backhaul networks, digital divide, lightweight optical cable, robust networks, rural communities. * To access the Recom
10、mendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii L series Supplement 22 (04/2016) FOREWORD The International Telecommunication Union (ITU) is the United Natio
11、ns specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations o
12、n them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of
13、ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is use
14、d for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the publi
15、cation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publication is required of any party. I
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17、ether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are cautioned
18、 that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.
19、L series Supplement 22 (04/2016) iii Table of Contents Page 1 Scope . 1 2 Abbreviations and acronyms 1 3 Key points of consideration for cost-effective, sustainable optical fibre backhaul solutions 1 3.1 System overview 1 3.2 Optical cables . 2 3.3 Transmission equipment . 3 3.4 Cable laying 3 4 Bes
20、t practices for cost-effective optical fibre backhaul solution 3 4.1 Optical cables . 4 4.2 Transmission equipment . 8 4.3 Cable laying 9 4.4 Comparison of cable construction costs . 10 Appendix I The relationship between the metrics in ITU-T L.1700 and the best practice solution . 12 Bibliography.
21、14 L series Supplement 22 (04/2016) 1 Supplement 22 to ITU-T L-series Recommendations ITU-T L.1700 Low-cost sustainable telecommunication for rural communications in developing countries using fibre optic cable 1 Scope This Supplement identifies low-cost, sustainable optical cable solutions for pote
22、ntial users of broadband digital services in remote or rural areas who are unlikely to gain such services when based solely upon conventional urban practices needing a positive return on investment, thus quickly and inclusively closing the digital divide. Best practice examples are included using li
23、ghtweight, thin and robust optical cables and commodity-type media converters. The results of field trials are presented in this Supplement. The cost of cables and their construction are estimated to be a fraction of the costs when using conventional optical cables with underground ducts. 2 Abbrevia
24、tions and acronyms This Supplement uses the following abbreviations and acronyms: CAPEX Capital Expenditure DIY Do It Yourself MTBF Mean Time Between Failure MTTR Mean Time Between Repair ODA Official Development Assistance OPEX Operating Expense USF Universal Service Fund US FCC United Sates Federa
25、l Communications Commission 3 Key points of consideration for cost-effective, sustainable optical fibre backhaul solutions 3.1 System overview Figure 1 provides an example of an optical cable backhaul layout. The optical cable backhaul connects the point of presence in the backbone with remote centr
26、es in rural/remote areas, and also with fixed access or mobile base stations, Wi-Fi stations and/or worldwide interoperability for microwave access (WiMAX) stations to the end users. The backhaul can take a ring form with redundant configuration for link survivability and improved resilience. Figure
27、 2 illustrates the best-of-class relationship between signal capacity vs. transmission distances without demanding electric power for the cable. Currently, typical practical capacities and distances in the backhaul are 10 Gbit/s/fibre-pair and 100 km, respectively. An optical cable solution is very
28、attractive from an environmentally conscious standpoint; well over 100 km can be passively covered with passive optical cable, while respecting the landscape and allowing ease of construction, maintenance and disposal without the use of heavy machinery. Optical cable solutions require no power gener
29、ators, solar panels, antennas or towers; only lightweight, manually-deployable robust cables are needed. In order for optical cable solutions to be widely and quickly deployed across difficult terrains and environments, the solutions should seek cooperation with the local community. This relationshi
30、p 2 L series Supplement 22 (04/2016) could reduce human interference, such as theft and/or vandalism. Affordability (capital expenditure (CAPEX) and operating expense (OPEX) including long-term total cost of ownership) would be improved if installation, operation, maintenance and repair of the infra
31、structure are supported by the benefitting local community, as they would be involved in a do-it-yourself (DIY) manner. 3.2 Optical cables Thin, lightweight robust optical cables accommodating up to 24 to 48 fibres are key to enabling a low CAPEX/OPEX backhaul solution across difficult terrains and
32、changeable landforms. With such cables, local communities can take part in system deployment, daily operations/maintenance, and service provisioning. Cables need to be waterproof, rodent-proof, highly durable against lateral pressure, and fire resistant to a certain extent. It is best if the same ca
33、ble structure allows direct burial application, direct surface application and, if required, aerial application. In fact, ITU-T SG15 is currently developing planned Recommendation on “Optical fibre cables for direct surface application (DSA)“. Since a length of such a cable, when installed on the su
34、rface, could later become covered by soil, sand, snow or a flood, and may need to be aerially suspended to cross a river, valley or road, planned Recommendation will be identifying the requirements for withstanding direct burying, submerging and aerial wiring. Figure 1 Optical cable backhaul layout
35、example L series Supplement 22 (04/2016) 3 Figure 2 Optical cable signal capacity vs. maximum transmission distances without amplification The use of such cables can avoid the need for precise cable-route surveys, cable-type selection, cable laying selection and cable length adjustment, and the need
36、 for joining different cable types at the construction site. Thus, the cable laying construction can be made simple and at low-cost over difficult terrain and changeable landforms. 3.3 Transmission equipment To simplify the construction, operation, maintenance and repair of the system, the use of co
37、mmodity-type transmission equipment is relatively low cost and readily available. The transmission equipment can be placed in a waterproof outdoor storage box to avoid the use of costly air-conditioned buildings. Power consumption of the equipment could then be covered by, for example, a solar panel
38、 and battery. Direct connection to the electric grid is not always necessary. 3.4 Cable laying Thin, lightweight and robust long-length optical cables are desired for direct surface, shallow direct burying, aerial wiring, long-length suspension and even submerged application for changeable terrain.
39、The cable laying cost can be further reduced if cable laying is largely provided by non-skilled local labour in a DIY manner, without the need for heavy machinery or special infrastructure such as cable ducts, trenches and poles. The direct underground burial of the cable, even shallowly by using ha
40、nd spades and pickaxes, would secure the link. Over specific terrain and landforms where cable laying through the ground is difficult, cable laying using a helicopter may be considered as a last resort. 4 Best practices for cost-effective optical fibre backhaul solution According to a 2013 report co
41、mmissioned by the Groupe Speciale Mobile (GSM) Association, more than one-third of the 64 Universal Service Funds (USFs) studied have yet to disburse any of the funds they have collected. Although the reason for this might be not very simple, it could partially be because meaningful and cost-effecti
42、ve real broadband solutions have not yet been made available, as evidenced by field data. It is desired that the best practice solution presented in this Supplement will lead to funding by USFs, subsidies or public funds, which will contribute to effectively reducing the digital divide. 4 L series S
43、upplement 22 (04/2016) 4.1 Optical cables All three types of optical cables shown in Figure 3 are thin, lightweight, robust, waterproof, rodent-proof, highly durable against lateral pressure, and fire resistant to a certain extent; thus, direct surface and direct-buried applications are acceptable.
44、Figure 3 Example optical cable types for direct surface and direct buried application The welded steel pipe, shown in Figure 3, accommodates up to 48 single-mode standard optical fibres. It is not necessary to use different types of cable structures for different outdoor environments, such as direct
45、-buried, submerged, aerial wiring or exposure to open air on ground surfaces. This not only avoids the need for a cable-route pre-survey, cable-type selection and cable length adjustment, but also the need for joining different cable types at the construction site. Thus, although the cable cost is a
46、 slightly higher than conventional optical cables without welded steel pipe, their cable laying construction over difficult terrain can be made at significantly low cost and more quickly. Figures 4 and 5 show a side view and cross-sectional view of an optical cable with a welded stainless-steel pipe
47、, where perfect welding is electrically confirmed in the process. This type of cable is widely commercially available, including for the submerged use under lakes and slow-moving rivers. Figure 4 Example optical cable with welded stainless-steel pipe L series Supplement 22 (04/2016) 5 Figure 5 Examp
48、le optical cable cross-sectional view of welded stainless-steel pipe Figure 6 shows a fire test at 1180 degrees C for 15 minutes. Figure 7 shows a lateral-pressure test where the fibre indicated no optical loss for up to 2 tons/100 mm of pressure applied from a heavy vehicle. Figure 6 Fire test resu
49、lts for optical cable with welded stainless-steel pipe 6 L series Supplement 22 (04/2016) Figure 7 Crush test results for optical cable with welded stainless-steel pipe Figure 8 shows optical cable rodent-proof testing. Whereas rats were able to fatally damage the conventional optical cable, the fibres survived when protected by the steel pipe. Figure 9 shows a cable vibration test for aerial wiring; no damage was observed against simulated cable vibration of one million cycles. Figure 8 Rodent-proof test results for optic
