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 23 (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 series Low-cost sustainable telecommunications for rural communications in developing countries using microwave and millimetre radio links ITU-T L-series Recommendations Supplement 23 ITU-T L-SERIES RECOMMENDATIONS ENVIRONMENT AND ICTS, CLIMATE CHANGE, E-WASTE, ENE
3、RGY 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 Infrastructure including node
4、 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 PASSIVE OPTICAL DEVIC
5、ES L.400L.429 MARINIZED TERRESTRIAL CABLES L.430L.449 For further details, please refer to the list of ITU-T Recommendations. L series Supplement 23 (04/2016) i Supplement 23 to ITU-T L-series Recommendations ITU-T L.1700 series Low-cost sustainable telecommunications for rural communications in dev
6、eloping countries using microwave and millimetre radio links Summary Supplement 23 to ITU-T L-series of Recommendations provides technical information about the use of microwave radio systems which are available for use in telecommunication networks for rural communications in developing countries.
7、Example applications include: high-capacity backbone networks, synchronous digital hierarchy (SDH) network systems, and use in enterprise networks and mobile backhauls. The attractive features of microwave systems for rural communications in developing countries are: independence from geographical f
8、eatures, such as mountains and archipelagos; rapid system integration at a low cost; robustness against disasters; and security against human interference. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L Suppl. 23 2016-04-27 5 11.1002/1000/12963 Keywords Microwave radio, m
9、illimeter-wave radio, mobile backhaul, mobile networks. * 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 23 (04/2016)
10、 FOREWORD The International Telecommunication 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 stu
11、dying technical, operating and tariff questions 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 gro
12、ups which, in turn, produce Recommendations on 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
13、ISO and IEC. NOTE In this publication, the expression “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 e
14、nsure, e.g., interoperability or applicability) 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
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17、e required to implement this publication. However, 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 2016 All rights reserved. No part of this publication may be repro
18、duced, by any means whatsoever, without the prior written permission of ITU. L series Supplement 23 (04/2016) iii Table of Contents Page 1 Scope . 1 2 Abbreviations and acronyms 1 3 System description 2 3.1 General overview 2 3.2 RF frequency and channel separation . 3 4 Technology . 4 4.1 Multi-lev
19、el QAM MODEM . 4 4.2 Equalizer . 4 4.3 Cross polarization interference canceller . 5 4.4 Automatic transmit power control 5 4.5 Forward error correction . 5 4.6 Adaptive coding and modulation 5 4.7 Protection 6 5 System performance and capacity 6 5.1 Capacity 6 5.2 Link budget . 6 Appendix I Technic
20、al characteristics of the 6-42 GHz band wireless link . 11 Appendix II Technical characteristics of the E-band (71-76 GHz, 81-86 GHz) wireless link 12 iv L series Supplement 23 (04/2016) Introduction Microwave radio is the most popular method used to connect multiple base stations of mobile communic
21、ation systems all over the world, and thus has been mass deployed in rural areas. Microwave systems have many advantages, such as: 1) high economic efficiency during construction period: short work period; work on points, not lines. 2) high reliability: established link designs; redundancy (optional
22、). 3) low cost in operation: small power consumption; highly integrated circuit; many advanced technologies for imperfection compensation. These advantages bring many benefits to the people in developing countries through provision of the economical mobile communication infrastructures. Microwave ra
23、dio systems should be included in guides on good practices for setting up low-cost sustainable telecommunication infrastructure for rural communications in developing countries. Moreover, considering the increase in demand for high capacity, millimeter-wave systems will be useful for concentrated st
24、ations. L series Supplement 23 (04/2016) 1 Supplement 23 to ITU-T L-series Recommendations ITU-T L.1700 series Low-cost sustainable telecommunications for rural communications in developing countries using microwave and millimetre radio links 1 Scope This Supplement provides technical information ab
25、out the use of microwave radio systems which are available for use in telecommunication networks for rural communications in developing countries. Example applications include: high-capacity backbone networks, synchronous digital hierarchy (SDH) network systems, and use in enterprise networks and mo
26、bile backhauls. The attractive features of microwave systems for rural communications in developing countries are independence from geographical features, such as mountains and archipelagos; short-term system integration at a low cost; robustness against disasters; and security against human interfe
27、rence. 2 Abbreviations and acronyms A/D Analogue to Digital converter ACM Adaptive Coding and Modulation ANSI American National Standards Institute ATPC Automatic Transmit Power Control CNR Carrier-to-Noise Ratio CS Channel Separation D/A Digital to Analogue Converter DC Direct Current DWRR Deficit
28、Weighted Round-Robin ETSI European Telecommunications Standards Institute FDD Frequency Division Duplex FEC Forward Error Correction FS Fixed Microwave Service IDU Indoor Unit IP Internet Protocol LDPC Low-Density Parity-Check LSI Large Scale Integrated circuit Mbps Mega bit per second NF Noise Figu
29、re ODU Outdoor Unit P-MP Point to Multi-Point P-P Point to Point QAM Quadrature Amplitude Modulation QPSK Quadruple Phase Shift Keying 2 L series Supplement 23 (04/2016) RF Radio Frequency RSL Received Signal Level Rx Receiver Tx Transmitter XPIC Cross polarization Interference Canceller 3 System de
30、scription 3.1 General overview Microwave radio systems are available in telecommunication and other communication networks at various locations. Figure 1 shows various applications of microwave systems: high-capacity backbone networks, SDH network systems, configure a companys enterprise network, an
31、d the last is used in mobile backhauls, which communicate between mobile base stations. Figure 1 Applications of fixed wireless service systems The attractive features of microwave systems are independence from geographical features such as mountains and archipelagos, a short-term, low-cost system i
32、ntegration period, robustness against disasters, and tightness in security such as in terrorism countermeasures that are increasing in importance. These features of microwave systems contribute to rapid and large-scale network L series Supplement 23 (04/2016) 3 deployments in order to quickly acquir
33、e cellular phone subscribers. This factor is one that promotes rapid growth in the market. Generally, millimeter-waves means from 30 GHz to 300 GHz frequency range. However, in this Supplement, over 60 GHz is called millimeter-waves, because up to 42 GHz is covered in the microwave systems. The 60 G
34、Hz band (sometimes called V-band) and 71-76/81-86 GHz band (E-band) are assigned for communication usage. Millimeter-wave systems also have attractive features like microwave systems as wireless solutions. The additional features of millimeter-waves are high-capacity transmission due to its wide ban
35、dwidth. Millimeter-waves are suitable for high-capacity transmission. However, its available link distance is limited due to absorption by air and rainfall. The link distance of V-band is strongly limited even under fine weather conditions due to oxygen absorption. Therefore, V-band is not suitable
36、for long link distances. On the other hand, this feature is preferable for avoiding interference to or from other systems. In terms of radio equipment hardware, millimeter-waves have good features, since the “all outdoor type“ configuration can be applied. An all outdoor type configuration means tha
37、t all functionalities of radio transmission equipment are included in one box, which can be installed on a pole with an antenna. This configuration has many preferable features for low-cost and sustainable infrastructures, low-cost, low-power consumption, no need for a shelter for an indoor unit (ID
38、U), etc. Figure 2 Features of a mobile backhaul The required capacity depends on the link characteristics. Microwave radio equipment can change the parameters, modulation and channel separation (CS). Same hardware can be applied to the various links. 3.2 RF frequency and channel separation Table 1 s
39、hows the major radio frequency (RF) bands and CSs applied to mobile backhaul and specified in the European Telecommunications Standards Institute (ETSI). For higher-frequency bands, more than 100 MHz CS will be available in the near future. Such wideband can support high-capacity transmission of mor
40、e than 500 Mbps. However, higher frequency bands have relatively large attenuation due to atmospheric gases, rainfall, and free space loss. Appropriate RF bands should be selected depending on the required conditions. Available minimum CS depends on the modulation scheme. 4 L series Supplement 23 (0
41、4/2016) Table 1 Major radio frequency bands and channel separations applied to mobile backhaul Band (GHz) Recommendation ITU-R Channel separation (MHz) 10.5 ITU-R F.747 7, 14, 28, 56 11 ITU-R F.387 7, 14, 28, 40, 56 13 ITU-R F.497 7, 14, 28, 56 15 ITU-R F.636 7, 14, 28, 40, 56 18 ITU-R F.595 13.75,
42、27.5, 55, 110 23 ITU-R F.637 7, 14, 28, 56, 112 26, 28 ITU-R F.748 7, 14, 28, 56, 112 31 ITU-R F.746 7, 14, 28, 56 32 ITU-R F.1520 7, 14, 28, 56, 112 38 ITU-R F.749 7, 14, 28, 56, 112 42 ITU-R F.2005 7, 14, 28, 56, 112 The entire V-band is from 57 to 66 GHz. The usable range in V-band is different f
43、or each country. The common usable range is from 59 to 63 GHz. The minimum CS is 50 MHz. The combining of multiple CSs, 100 MHz, 150 MHz, etc., is allowable. The E-band is 71-76/81-86 GHz. The set of 5 GHz bandwidth is used for dual direction communication. The minimum CS is basically 250 MHz. The o
44、ne-quarter or one-half is also available as the narrow band. The maximum CS depends on the regulation in each country. ETSI standard provides the specifications for up to 2 GHz CS. 4 Technology 4.1 Multi-level QAM MODEM Quadruple phase shift keying (QPSK) and multi-level quadrature amplitude modulat
45、ion (QAM) from 16 QAM to 256 QAM are generally adopted for a modulation scheme for microwave systems. Recently, according to market demands for high capacity, over-256 QAM modulation schemes have been introduced. However, the higher modulation requires a higher carrier-to-noise ratio (CNR). In the d
46、emodulator, coherent detection is executed precisely with many functions, such as equalization and clock synchronization. Recently, these complex functionalities including modulator are implemented in one highly integrated large-scale integrated (LSI) circuit. Therefore, the cost of the MODEM portio
47、n has become dramatically cheaper during the past two decades. The same hardware can be available for a wide range of symbol rates by changing sampling rate at the digital to analogue converter (D/A), analogue to digital converter (A/D) and digital signal processing circuits. 4.2 Equalizer In the lo
48、wer RF band below 10 GHz, fixed microwave service (FS) applications are usually for transport networks where FS links are deployed with long-hop distance. In such cases, the system must prepare a counter measure against fading. Adaptive equalization is a mandatory function. Even for the higher RF ba
49、nd, an equalizer is needed to compensate for imperfections in hardware. The equalizers contribute to performance improvement and equipment cost reduction, because introduction of an equalizer enables the use of cheaper RF devices that have insufficient frequency characteristics in the wireless equipment. L series Supplement 23 (04/2016) 5 4.3 Cross polarization interference canceller Polarization multiplexing can achieve double capacity without bandwidth expansion. However, the interference between two polarizations causes deg
