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 30 (10/2016) 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 Setting up a low-cost sustainable telecommunication network for rural communications in developing countries using cellular network with capacity transfer ITU-T L-series Recommendations Supplement 30 ITU-T L-SERIES RECOMMENDATIONS ENVIRONMENT AND ICTS, CLIMATE CHAN
3、GE, E-WASTE, ENERGY EFFICIENCY; CONSTRUCTION, 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 Infrastructur
4、e including node element (except cables) L.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 PASSI
5、VE OPTICAL DEVICES L.400L.429 MARINIZED TERRESTRIAL CABLES L.430L.449 For further details, please refer to the list of ITU-T Recommendations. L series Supplement 30 (10/2016) i Supplement 30 to ITU-T L-series Recommendations ITU-T L.1700 Setting up a low-cost sustainable telecommunication network fo
6、r rural communications in developing countries using cellular network with capacity transfer Summary Supplement 30 to ITU-T L-series Recommendations provides a description of the cellular network with capacity transfer system that has been developed taking into account specific requirements for comm
7、unications in rural and remote areas with special attention to low expenditure on all components of the system, focusing on low operating cost, low power consumption, very effective coverage zones and low requirements for maintenance of the system. The key benefit is achieved by relaying of the cell
8、ular air interface in a frequency band other than standard cellular, which allows the substitution of a significant part of the base station (BS) and microwave link (ML) or optical fibre links interconnecting them. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L Suppl. 30
9、2016-10-14 5 11.1002/1000/13153 Keywords Base station (BS), capacity transfer repeater (CTR), cellular network, coverage area, global system for mobile communication (GSM), long-term evolution (LTE), long-term evolution-advanced (LTE-A), microwave links (ML), universal mobile telecommunication syste
10、m (UMTS). * To access the Recommendation, 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 30 (10/2016) FOREWORD The International Telecommunication
11、Union (ITU) is the United Nations 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 question
12、s and issuing Recommendations on 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
13、 these topics. The approval of 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 exp
14、ression “Administration“ is used 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
15、) and compliance with the publication 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 publicat
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18、ver, implementers are cautioned 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 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the pr
19、ior written permission of ITU. L series Supplement 30 (10/2016) iii Table of Contents Page 1 Scope . 1 2 Abbreviations and acronyms 1 3 System description 2 3.1 General overview 2 3.2 Functional description 5 3.3 Developed equipment performance and capacity . 10 3.4 General specification of GSM CTR
20、equipment . 11 3.5 General specification of UMTS or LTE CTR equipment 12 4 Best practice 13 4.1 Capacity transfer repeater implementation to provide highways and railways network coverage . 13 4.2 Capacity transfer repeater implementation to provide coverage in settlements situated up to 30 km away
21、from main routes 13 4.3 Capacity transfer repeater implementation in sparsely populated areas. 14 4.4 Capacity transfer repeater implementation in towns and settlements 15 4.5 Capacity transfer repeater sharing 16 4.6 Field test of a cellular system with capacity transfer . 17 5 Conclusion 18 Biblio
22、graphy. 19 iv L series Supplement 30 (10/2016) Introduction Existing mobile network systems are primarily defined for urban areas where the necessary support infrastructure (adequate power, building or shelter, accessibility, skilled manpower to operate etc.) for setting up a telecommunication netwo
23、rk is assumed to be in place. Hence current systems do not meet rural specific requirements and cannot be mass deployed. A cellular network with capacity transfer is a very attractive mobile network system that can be used in rural areas and provides a very low capital and operating cost, a very low
24、 power consumption, a very effective coverage of sparsely populated and scattered population clusters, a very quick deployment of the system to give “last-mile“ service for customers with high economic efficiency. Fundamentally, the key benefit is achieved by relaying of the cellular air interface i
25、n a frequency band other than standard cellular, which allows the substitution of significant part of the base station (BS) and microwave link (ML) or optical fibre links interconnecting them. L series Supplement 30 (10/2016) 1 Supplement 30 to ITU-T L-series Recommendations ITU-T L.1700 Setting up
26、a low-cost sustainable telecommunication network for rural communications in developing countries using cellular network with capacity transfer 1 Scope This Supplement provides a system description of the cellular network with capacity transfer, functional description, system performance and capacit
27、y, coverage areas and provided advantages in comparison with standard cellular network in economic, power consumption, capital and operating cost, maintenance, rapid deployment and quality of service. 2 Abbreviations and acronyms This Supplement uses the following abbreviations and acronyms: BS Base
28、 Station BS-R transfer unit CAPEX Capital Expenditure CDMA Code Division Multiple Access CTR Capacity Transfer Repeater DRM+ Digital audio broadcasting system DU Digital Unit EDGE Enhanced Data rates for GSM Evolution ERP Effective Radiated Power GPRS General Packet Radio Service GSM Global System f
29、or Mobile communications HSPA High-Speed Packet Access LTE Long-Term Evolution LTE-A Long-Term Evolution-Advanced ML Microwave Link MS Mobile Station (subscriber terminal) OFC Optical Fibre Cable OPEX Operating Expense PS Power Supply QoS Quality of Service RAN Radio Access Network RC Radio frequenc
30、y Converter RF Radio Frequency RRH Remote Radio Head SDR Software-Defined Radio 2 L series Supplement 30 (10/2016) TRX Transceiver UMTS Universal Mobile Telecommunication System X CTR transceiver 3 System description 3.1 General overview The cellular network with capacity transfer principle is illus
31、trated in Figure 1. In the traditional cellular network topology, the capacity is statically distributed among BSs of the radio access network (RAN). The cellular network with capacity transfer is built around a central BS where radio resource is concentrated and distributed to light repeater-like s
32、ervice stations. That principle allows the achievement of high efficiency and flexibility in the cellular network. Figure 1 Cellular network with capacity transfer principle The cellular network with capacity transfer principles are implemented in the capacity transfer repeater (CTR). CTRs are bidir
33、ectional amplifiers that perform reception, selection (filtering) and amplification of radio signals, as well as the conversion of their carrier frequency from the cellular band to a different frequency range (usually higher) and vice versa. Variable gain allows the establishment of the necessary zo
34、ne of radio coverage. CTR transfers radio signals from the base station (BS) of a cellular network to the mobile station (MS) subscriber terminal and in the reverse direction. The solution allows the expansion of the coverage zone of the BS with a simultaneous increase of the overall channel capacit
35、y of the cellular network with the relay of the whole sector. As a result, the number of required BSs and corresponding microwave links (MLs) in a cellular network is significantly reduced, as well as the total cost of the system. L series Supplement 30 (10/2016) 3 The expanded coverage zone consist
36、s of relayed sectors of a single BS with no intercell handovers between service areas of the CTRs connected to the same BS. In this case, only intra-cell inter-sector handovers take place, which, depending on the standard and the equipment, could be handled by the BS itself. This fact enables signif
37、icant reductions of signalling overhead and call drops, which in turn improve quality of service (QoS), especially in complex coverage areas. Usage of the frequency bands outside the cellular frequency band by CTRs for relaying dramatically reduces the impact of intersystem interference in compariso
38、n with common repeaters. There are a number of options for relay channel arrangement. Out of the cellular bands: ML bands; whitespaces; licensed and unlicensed bands. In the cellular bands: regionally unused cellular bands and sub-bands; locally unused cellular spectrum; reformed bands and sub-bands
39、. The low power consumption of CTRs allows usage of alternative sources of power (solar panels, wind power) that greatly facilitates the provision of radio coverage in sparsely populated and remote areas. See Figure 2. 4 L series Supplement 30 (10/2016) a) Typical site of a base station b) Typical c
40、apacity transfer repeater site Figure 2 The cellular network with capacity transfer assumes changes in cellular network topology. However, it does not require changes to cellular communication standards. It provides a number of considerable advantages to traditional cellular networks: One CTR, consu
41、ming less than 180 W per sector for the global system for mobile communications (GSM) and 60 W per sector for universal mobile telecommunication system/long-term evolution (UMTS/LTE), substitutes for BS, ML or optical fibre and power supply (PS) that can consume 1.5-3 kW; Reduction of operating expe
42、nse (OPEX) by more than two to three times, while preserving an equivalent coverage and capacity; Cooperative service for two to three different operators (RAN sharing) with capital expenditure (CAPEX) and OPEX reduction by two to four times per site for each operator; L series Supplement 30 (10/201
43、6) 5 Exclusion of inter-cell handovers between CTR sites connected to one BS; Reduction of relay channel bandwidth compared to standard ML by 1.3 to six times depending on cellular standard and conditions; RAN capacity redistribution to handle local areas overloads; Variable topology of cellular net
44、work achieving call drops reduction, improved QoS, indoor and underground coverage without handovers to above-ground network; Compatibility with any vendor BSs; Compatibility with any BS software versions, no need for software updates; Invariance to cellular standards and their versions. Principles
45、of cellular network with capacity transfer are described in b-RU 2279764 C1, b-US 8,289,888 B2, b-EP 1890399 B1, b-CN 101006665 B, b-India 258620 and b-UA 91347 C2. 3.2 Functional description The main functional purpose of the CTR is to transfer capacity of one or more sectors of the BS to remote ar
46、eas. In this case, the entire infrastructure needed for BS functioning is placed at the BS site. Figure 3 shows an example of the highway coverage by GSM BSs. Each BS includes two transceivers (TRXs), a digital unit (DU) and a PS. Base station BS1 is connected to the core network by an optical fibre
47、 cable (OFC). BSs are interconnected by MLs. All BSs at the sites are supposed to have a similar configuration each one is installed in the container close to the tower, on the top of which receiving and transmitting GSM antennas are installed, as well as an ML and its antenna equipment. Container B
48、Ss site design requires significant CAPEX. TRX cable connections of the BS installed in the container with the antennas make a significant attenuation of signals during transmission and reception to compensate, which is necessary to increase the power of the BS transmitter. Power consumption of the
49、site, taking into account the air conditioner installed in the shelter, is 3-5 kW. The use of distributed BSs, where radio frequency (RF) remote radio head (RRH) units are placed next to the antennas and baseband DUs are installed in a climatic cabinet, helps reduce the power consumption of the sites down to 1-2 kW. 6 L series Supplement 30 (10/2016) Figure 3 Cellular network with standard BSs Figure 4 shows the scheme of coverage of the same route using capacity transfer repeaters
