1、INTERNATIONAL TELECOMMUNICATION UNION HANDBOOK DIGITAL RADIO-RELAY SYSTEMS RADIOCOMMUNICATION 6UREAU Geneva, 1996 COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesTHE RADIOCOMMUNICATION SECTOR OF THE ITU The role of the Radiocommunicati
2、on Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and p
3、olicy hnctions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assem- blies supported by Study Groups. Contact address for inquiries about radiocommunication matters: ITU Radiocommunication Bureau Place des Nations CH - 12 1
4、1 Geneva 20 Switzerland Telephone +41 22 730 5800 Fax +41227305785 Internet brmailitu.int X.400 S=brmail; P=itu; A=400net; C=ch Contact address for orders of ITU publications: ITU Sales and Marketing Service Place des Nations CH-121 1 Geneva 20 Switzerland Telephone +41 22 730 6141 English Telephone
5、 +41 22 730 6142 French Telephone +4 1 22 730 6 143 Spanish Fax +41227305194 Telex 421 O00 uit ch Telegram ITU GENEVE Internet salesitu.int X.400 S=sales; P=itu; A=400net; C=ch O ITU 1997 All rights reserved. No part of this publication may be reproduced or utilised in any form or by any means, elec
6、tronic or mechanical, including photocopying and microfilm, without written permission from the ITU. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesINTERNATIONAL TELECOMMUNICATION UNION HANDBOOK DIGITAL RADIO-RELAY SYSTEMS RADIOCOMMUN
7、ICATION 6UREAU Geneva, 1996 COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesSTD*ITU-R HDBK HDR-ENGL L77b E 4855232 0543734 033 E . . 111 . TABLE OF CONTENTS Page CHAPTER 1 . INTRODUCTION 1 1 . 1 INTENT OF HANDBOOK . 1 1.2 EVOLUTION OF
8、DIGITAL RADIO-RELAY SYSTEMS 2 1.3 DIGITAL RADIO-RELAY SYSTEMS AS PART OF DIGITAL TRANSMISSION NETWORKS . 3 1.4 GENERAL OVERVIEW OF THE HANDBOOK 5 1.5 OUTLINE OF THE HANDBOOK . 5 CHAPTER 2 . BASIC PRINCIPLES 7 2.1 DIGITAL SIGNALS. SOURCE CODING. DIGITAL HIERARCHIES AND MULTIPLEXING 7 2.1 . 1 Digitiza
9、tion (A/D conversion) of analogue voice signals . 2,1.2 Dlglhzatlon of video signals 2.1.3 Non voice services, ISDN and data signals . 2.1.4 Multiplexing of 64 kbit/s channels 2.1 . 5 Higher order multiplexing, Plesiochronous Digital Hierarchy (PDH) 2.1.7 Synchronous multiplexing, Synchronous Digita
10、l Hierarchy (SDH) . 2.1.6 Other multiplexers . 2.1.7.1 General pnnclples 2.1.7.2 Synchronous multiplexing scheme 2.1.7.3 Overhead functions 2.1.7.4 The Sub-STM-1 signal format 2.1.7.5 ATM transport in the SDH, SDH transport via PDH signals 2.1.8 Interconnection at baseband, physical interface charac
11、teristics 2.1.9 Jitter and wander timing and synchronization . 7 8 8 8 8 11 11 11 12 15 16 18 19 20 2.2 FUNDAMENTALS OF TERRESTRIAL DIGITAL RADIO-RELAY SYSTEMS . 20 2.2.1 Architecture of digital radio-relay systems . 22 2.2. 1 . 1 Digital transmitter . 22 2.2.1.2 Digital receiver 24 2.2.1.3 Radio tr
12、ansmitter and receiver 26 2.2.1.4 Channel combining and antenna considerations . 28 2.2.1.5 Radio switching section 29 Previous page is blank COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesSTD-ITU-R HDBK HDR-ENGL L976 lsl 4855212 0543
13、735 T7T m . iv . CHAPTER 3 . LINK DESIGN CONSIDERATIONS . 3.1 APPLICATIONS OF DIGITAL RADIO-RELAY SYSTEMS 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 General . Available frequency bands Coexistence between analogue and digital radio systems . Digital channel capacity Digital networks 3.1 .5 . 1 Long haul di
14、gital radio systems 3.1 S.2 Short haul digital radio systems 3.1 S.3 Digital radio access networks Radio Local Area Networks (RLAN) 3.1.6.1 General 3.1.6.2 Frequency bands 3.1.6.3 Multiple access and modulation 3.1.6.4 System configuration . 3.1.6.5 Examples of RLANs . 3.2 PERFORMANCE AND AVAILABILI
15、TY OBJECTIVES 3.2.1 Hypothetical digital connection. path and section . 3.2.2.1 Error performance parameters and objectives based on ITU-T Recommendation G.82 1 3.2.2.2 Error performance parameters and objectives based on ITU-T Recommendation G.826 3.2.3 Availability performance parameters and objec
16、tives 3.2.4 Bringing-into-service and maintenance . 3.2.4.1 Relationship between performance limits and objectives . 3.2.4.2 Performance limits for bringing-into-service 3.2.2 Error performance parameters and objectives . 3.3 UPGRADING FROM ANALOGUE TO DIGITAL RADIO SYSTEMS 3.3.1 3.3.2 3.3.3 3.3.4 3
17、.3.5 3.3.6 3.3.7 3.3.8 3.3.9 Advantages ofa new digital microwave system . Existing analogue microwave system characteristics Difficult digital microwave paths Antenna feeder systems . Digital microwave system overbuild . Analogue/digital RF coupling arrangements . Analogue spur links . Analogue-to-
18、digital circuit cutover phases The clrcult cutover . 3.4 W CHANNEL ARRANGEMENTS 3.4.1 Introduction . 3.4.2 Spectrum related parameters . 3.4.3 Type of channel arrangement 3.4.5 Intra-system and inter-system interference criteria . 3.4.4 Homogeneous pattern and channel subdivision 34 34 34 35 38 39 4
19、1 41 41 42 42 42 43 43 44 45 46 46 47 47 47 49 54 57 58 59 60 60 62 62 63 63 63 64 64 64 65 65 65 66 69 70 COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services-v- 3.5 BAND SHARING WITH OTHER SERVICES 3.5.1 Assessment of interference from o
20、ther services 3.5.1 1 General 3 . 5. 1.2 Degradation in performance and availability 3.5.1.3 Assessment of aggregate effects of interference from various . sources . 3.5.2 Basic parameters for sharing considerations . 3 52.1 Receiver side . 3.5.2.2 Transmitter side . Study Group 9 . 3.5.3 Status of
21、studies on frequency sharing within Radiocommunication References to Chapter 3 . CHAPTER 4 . DESIGN PARAMETERS . 4.1 PROPAGATION RELATED ISSUES 4.1.1 Concept of free space loss . 4.1.2 Visibility 4.1.2.1 Refractive aspects 4.1.2.2 Path profiles, clearance and obstructions 4.1.2.3 Diffraction aspects
22、 . 4.1.3 Surface reflection . 4.1.3.1 Introduction . 4.1.3.2 Specular reflection from a plane Earth surface . 4.1.3.3 Specular reflection from a smooth spherical Earth . 4.1.4 Atmospheric multipath 4.1.4.1 Introduction . 4.1.4.2 Fading due to multipath and related mechanisms . 4.1.4.4 Outage computa
23、tion methods 4.1.5 Precipitation attenuation 4.1.3.4 A practical method to determine specular ground reflections . 4.1.4.3 Atmospheric multipath modelling . 4.1.6 Scattering property 4.1.6.1 Rain scattering . 4.1.6.2 Terrain scattering . 4.1.7 Polarization 4.1.7.1 General aspects 4.1.7.2 Explanation
24、 for XPD degradation mechanisms 4.1.7.3 Computation of cross-polarization degradation 4.1 . 8 Gaseous attenuation . 4.2 EQUIPMENT RELATED ASPECTS . 4.2.1 Baseband processing . 4.2. 1 . 1 General baseband processing function 4.2.1.2 Radio specific processing functions for baseband signals 73 73 73 73
25、 75 77 77 79 82 83 86 86 86 87 87 91 93 98 98 98 98 102 103 103 104 110 116 119 123 123 124 124 124 125 126 128 131 131 131 133 COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesSTD-ITU-R HDBK HDR-ENGL 379b M 4855232 0543737 8YZ . vi . 4
26、.2.2 Modulation and demodulation . 4.2.2.1 Basic principles . 4.2.2.2 Linear modulation schemes . 4.2.2.3 Non-linear modulation schemes 4.2.2.4 Coded modulation . 4.2.2.5 Spectrum shaping 4.2.2.6 Probability of error for the additive white Gaussian noise channel . 4.2.2.7 Aspects relevant to demodul
27、ation process 4.2.2.8 Modem functional blocks 4.2.3 Transmitter 4.2.3.1 Local oscillator (LO) . 4.2.3.2 Frequency conversion in the mixer . 4.2.3.3 Transmission power versus peak factor and modulation format “(back-off)” with and without linearisation 4.2.3.4 Power amplifier . 4.2.3.5 Spurious emiss
28、ions (types and requirements) interndexternal) . 4.2.3.7 Filtering (WAF) 4.2.4 Receiver . 4.2.4.1 Frequency conversion 4.2.4.2 Filtering . 4.2.4.3 Noise figure . 4.2.4.4 Required bandwidth 4.2.4.5 Signature 4.2.5.1 General 4.2.3.6 Linearisation (requirements and techniques) 4.2.5 Radio protection sw
29、tchmg 4.2.5.2 Types of protection arrangements . 4.2.5.3 Architecture of radio protection switching 4.2.5.4 Protection switching on set stand-by basis 4.2.5.6 Factors influencing the choice of switching criteria . 4.2.5.7 Calculation of link unavailability 4.2.6 Antennas and feeder systems . 4.2.6.1
30、 Fundamentals of radio-relay antennas . 4.2.6.2 Parabolic antenna 4.2.6.3 Horn reflector antenna . 4.2.6.4 High performance antenna 4.2.6.5 Fundamentals of feeder systems 4.2.6.6 System multiplexing filter . 4.2.5.5 Multi-line switching 4.3 COUNTERMEASURES . 4.3.1 General explanation . 4.3.1.1 Purpo
31、se of countermeasures 4.3.1.2 Classification of countermeasures . 4.3.1.3 Evaluation of countermeasures . 135 135 136 138 139 141 146 150 159 168 168 169 170 170 174 174 177 177 177 178 181 182 182 182 182 182 183 184 184 185 186 186 186 190 193 194 197 203 205 205 205 206 208 COPYRIGHT Internationa
32、l Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services4.3.2 4.3.3 4.3.4 4.3.5 4.3.6 4.3.7 4.3.8 4.3.9 Adaptive equalization 4.3.2.1 Basic principles . 4.3.2.2 Equalization structures 4.3.2.3 Adaptation algorithms . Interference cancellers . 4.3.3.2 Interference c
33、ancellers . 4.3.3,l Basic principles . 4.3.3.3 Cross-polarization interference cancellers Adaptive transmitter power control . 4.3.4.1 Basic principles . 4.3.4.2 Applications Data coding and error correction . 4.3.5.1 Forward error correction . 4.3.5.2 Coded modulation . Space diversity . 4.3.6.1 Ba
34、sic principles . 4.3.6.2 Methods of obtaining diversity signals . 4.3.6.3 Signal control methods 4.3.6.4 Improvement effects 4.3.6.5 Triple and quadruple diversity Angle diversity 4.3.7.1 Basic principles . 4.3.7.2 Applications Polamation diversity . Frequency diversity . 4.3.9.1 Concept of frequenc
35、y diversity . 4.3.9.2 Improvement effect . 4.3.1 O Synergistic effects . 4.3.1 O . 1 Space diversity and adaptive equalizers 4.3.10.2 Space and frequency (hybrid) diversity . 4.3.1 1 Multi-canier transmission . References to Chapter 4 . CHAPTER 5 . LINK ENGINEERING . 5.1 GENERAL NETWORK AND LINK DES
36、IGN CONSIDERATIONS 5.1.1 Performance objectives and network planning aspects . 5.1.2 Link and hop design objectives . 5.2 PRELIMINARY RADIO ROUTE AND SITE SELECTION 5.2.1 Introduction . 5.2.2 Contour maps 5.2.3 Identification of route alternatives . 5.2.4 Use of existing infrastructure and site shar
37、ing 5.2.5 Preliminary path profiles . 5.2.6 Preliminary performance prediction calculations 208 208 209 211 214 214 215 216 219 219 220 221 221 222 230 230 231 234 238 247 252 252 252 256 257 257 257 259 259 261 262 266 273 273 273 273 274 274 274 274 275 275 276 COPYRIGHT International Telecommunic
38、ations Union/ITU RadiocommunicationsLicensed by Information Handling ServicesSTD.ITU-R HDBK HDR-ENGL L77b m 4855232 0543939 bL5 W . . VI11 . 5.2.7 Selection of route alternatives . 5.2.8 Cost assessment . 5.2.9 Selection of “best route alternatives” 5.2.1 O Field surveys 5.2.10.1 The purpose of fiel
39、d surveys . 5.2.10.2 Location of sites, obstacles and roads . 5.2.10.3 Geographical characteristics of roads and sites . 5.2.10.4 Survey of the terrain in between sites . 5.2.10.5 Additional issues regarding surveys of existing stations 5.2.10.6 Survey reporting 5.2.1 1 Final radio route and site se
40、lection 5.3 LINK DESIGN PROCEDURES . 5.3.1 Introduction . 5.3.2 Error performance and availability objectives . 5.3.3 Frequency band and channel selection 5.3.3.1 Frequency band characteristics . 5.3.3.2 Frequency band and channel selection 5.3.4 Path engineering 5.3.4.1 General considerations 5.3.4
41、.2 Free-space propagation, receiver threshold, system gain and flat fade margin 5.3.4.3 Outage time prediction for single frequency clear air fading 5.3.5 Interference considerations 5.3.5.1 Spectrum masks and cross-polarization discrimination PD) 5.3.5.2 The threshold-to-interference ratio 5.3.6 Ou
42、tage prediction for rain . 5.3.7 Short-hand design guide 5.4 LINK AVAILABILITY ENGINEERING 5.4.1 Introduction . 5.4.2 Factors affecting availability . 5.4.3 Apportionment of availability objectives 5.4.4 Equipment contribution to unavailability 5.4.5 Effectiveness of maintenance arrangements 5.4.6 C
43、alculation of equipment unavailability . 5.4.7 Clear air propagation contribution to unavailability . 5.4.8 Ram-induced unavallablhty 5.4.9 Use of redundancy to improve link availability . . 5.4.1 O Calculation of link unavailability ANNEXES to Chapter 5 . Performance prediction methods . Introducti
44、on 276 276 276 276 276 277 277 277 277 278 278 278 278 279 281 281 282 282 282 282 283 285 285 285 289 291 293 293 293 293 294 294 295 295 295 296 296 297 297 COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesSTD-ITU-R HDBK HDR-ENGL 1796
45、 E 4655212 0543740 337 E . ix- ANNEX I to Chapter 5 . Performance prediction. method 1 (fade margin method) . 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 Introduction . Single frequency fading . Broadband or dispersive fading . 5.1.3.1 A channel model 5 .I. 3.2 Equipment signature 5.1.3.3 Radio outage
46、 due to dispersive effects 5.1.3.4 Scaling of signatures with symbol rate . The total outage . Outage time reduction achieved by diversity systems 5.1.5.1 The concept of dispersive fade margin 5.1.5.3 Outage time reduction by diversity systems . 5.1.5.5 Total outage time in diversity systems Outage
47、time reduction achieved by equalizers Combined use of equalizer and diversity - the . synergistic effect 5 .I. 3.5 Results of propagation measurements . 5.1.5.2 Relationship with the Bellcore dispersive fade margin . 5 .I. 5.4 Space diversity and frequency diversity improvement factors ANNEX II to C
48、hapter 5 . Performance prediction. method 2 (normalized signature method) 5.11.1 Flat fade margin and noise contribution 5 .I I. 1 . 1 Noise budget assignment . 5 .I I. 1.2 Calculation of noise component 5.11.2 Dispersive fade margin based on normalized signature method 5.11.3 Improvement of outage
49、probability by countermeasures 5 .II. 3.1 General 5.11.3.2 Examples of improvement factors . 5.11.4 General assessment procedure . ANNEX III to Chapter 5 - Performance prediction, method 3 (“Linear amplitude dispersion” (LAD) 5.111.1 5 .II 1.2 5 .II 1.3 5.111.4 5.111.5 5.111.6 5.111.7 5.111.8 statistics method) . Basis of the method . The fading model. parameter distributions and assumptions Signature scaling and normalised system parameters . Outage prediction for diversity Simplified outage prediction for non-diversity and diversity Example application of the prediction method and comp
