Project P816-PF
Implementation frameworks for integrated wireless-
optical access networks
Deliverable 3
Implementation St...
EURESCOM PARTICIPANTS in Project P816-PF are:

•   Finnet Group
•   British Telecommunications plc
•   Community of Yugosl...
Deliverable 3                                              Implementation Strategies




Preface
     Today, one of the ke...
Implementation Strategies                                                 Deliverable 3




Executive Summary
     This de...
Deliverable 3                                                Implementation Strategies



therefore interesting cellular a...
Implementation Strategies                                                   Deliverable 3



•   the number of BS which ha...
Deliverable 3                                     Implementation Strategies




List of Authors
      Antti Siitonen      ...
Implementation Strategies                                                                                             Deli...
Deliverable 3                                                                             Implementation Strategies



  7...
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Abbreviations
     1G, 2G, 3G   ...
Deliverable 3                                          Implementation Strategies



HIPERLAN         High Performance Radi...
Implementation Strategies                                        Deliverable 3



WDM                Wavelength Division M...
Deliverable 3                                               Implementation Strategies




Introduction
     In Task 2 of t...
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1     Scenarios for the intro...
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                   ...
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1.2   Evaluation of introduction...
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            The architecture may...
Deliverable 3                                               Implementation Strategies



Distribution services are uni-dir...
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    provides the capacity of 1 G...
Deliverable 3                                                 Implementation Strategies




2     Deployment and implement...
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•    wide ...
Deliverable 3                                                 Implementation Strategies



mm-wave optical feeder: OSSB is...
Implementation Strategies                                                             Deliverable 3




  TEF             ...
Deliverable 3                                                         Implementation Strategies




        Technology    ...
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         ...
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2.3.2   UMTS Urban Microcellula...
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2.3.4   LMDS



              ...
Deliverable 3                                                Implementation Strategies




3     Comparative costings for ...
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3.2   The wireless architectur...
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                               ...
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•   Power Supply: Power supplies wi...
Deliverable 3                                               Implementation Strategies




4     Frequency survey and regul...
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                              U...
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DECT: Directive 91/287/EEC design...
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      Systems (MVDS). In the 2...
Deliverable 3                                                Implementation Strategies



based on different technologies ...
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  1. 1. Project P816-PF Implementation frameworks for integrated wireless- optical access networks Deliverable 3 Implementation Strategies Suggested readers: • Public network operators studying potential upgrade possibilities for their access network architectures. • Manufacturers of radio and optical equipment. For Full Publication February 2000
  2. 2. EURESCOM PARTICIPANTS in Project P816-PF are: • Finnet Group • British Telecommunications plc • Community of Yugoslav Posts, Telegraphs and Telephones • Telecom Italia S.p.a. • Deutsche Telekom AG • MATÁV Hungarian Telecommunications Company Ltd. • Slovenské telekomunikácie, a.s. • Telenor AS • Telia AB This document contains material, which is the copyright of certain EURESCOM PARTICIPANTS, and may not be reproduced or copied without permission. All PARTICIPANTS have agreed to full publication of this document. The commercial use of any information contained in this document may require a license from the proprietor of that information. Neither the PARTICIPANTS nor EURESCOM warrant that the information contained in the report is capable of use, or that use of the information is free from risk, and accept no liability for loss or damage suffered by any person using this information. This document has been approved by EURESCOM Board of Governors for distribution to all EURESCOM Shareholders. © 1998 EURESCOM Participants in P816
  3. 3. Deliverable 3 Implementation Strategies Preface Today, one of the key features describing the global development of telecommunications is the continuing increase in customer demand for bandwidth intensive applications and mobile and personal communications. Customers require higher and higher data rates, extending broadband from the fixed into the wireless/mobile networks. There are different access media solutions for the last mile to the subscriber. An essential technology for integrating wireless and optical access is Hybrid Fibre Radio (HFR). This combines two media, fibre optics and radio, where radio provides flexible broadband access to a remotely located antenna site, which in turn is connected via fibre to the telecommunications network. The P816 Project studied extensively how the synergy effect based on the integration of broadband wireless and optical networks will lead to a flexible access network structure, capable of offering broadband mobility functions to the users of telecommunication services. The present P816 Deliverable 3 is providing an identification and comparison of hybrid radio/optical access implementation strategy, introduction scenarios, and recommendations for the operators with respect to regulatory, technical, and economic aspects. Deliverable 3 is recommended to readers such as managers and planners looking for ways to upgrade their access network architecture, and for manufacturers of radio and optical equipment interested in tapping this future market. © 2000 EURESCOM Participants in Project P816-PF page i (ix)
  4. 4. Implementation Strategies Deliverable 3 Executive Summary This deliverable provides an overview of possible implementation strategies of integrated wireless-optical access networks with a focus on hybrid fibre-radio (HFR) technology. Commercial analogue optical feeders are already available for 1st and 2nd generation (1G and 2G) cellular systems, and they are useful for connecting remote antenna units and at the same time allow to centralise base station equipment. There are different types of feeders on the market with different performance parameters and complexity. These feeders are currently mainly deployed in niche markets. As 3G radio systems are gradually deployed, HFR will become an important technology that can reshape the cellular and fixed wireless access networks. Who should read this, and why it is important This document is aimed at network operators studying potential upgrade possibilities of their access network architectures. It also addresses manufacturers of radio and optical equipment in order to get a common understanding of operators requirements. The document provides recommendations on the implementation of optical feeders for different scenarios. These recommendations are supported by economical studies. The benefits for your company HFR can give the following benefits: • Reliability and low maintenance costs • Future proof architecture, no exploding costs for each new arriving application. • Adaptation to varying regulatory constraints, and the ability to support multiple radio services Aspects addressed by this deliverable HFR systems are reviewed and their integration in existing and planned networks is evaluated. The results are also compared with broadband access technologies such as Hibryd Fibre Coax (HFC) and Fibre to the Home (FTTH). The economic aspects for a range of HFR systems and their integration in different wireless access technologies are analysed. Frequency issues, licensing and commercial availability in different time frames have been considered. Together with a detailed manufacturer survey this lead to recommendations and implementation guidelines. The main results HFR may be integrated in the following wireless systems: • Fixed wireless access: WLL, HIPERACCESS, LMDS. • Cellular systems : GSM-900, DCS-1800, IS-95, WCDMA, etc. • Indoor W-LANs: HIPERLAN 2, IEEE802.11. • Satellite access systems Current applications of HFR are mainly focusing on installing antennas in distant radio dark locations which are otherwise difficult to reach. However, HFR may find a larger market acceptance in wireless hotspot places, where cell sizes are in the micro and picocell domain, e.g. in town centres, as it allows to centralise base stations. HFR feeders for 2G and 3G radio systems (fradio < 10GHz) are already available. GSM, GPRS, EDGE (~2001) and UMTS (~2003) in urban and suburban areas are page ii (ix) © 2000 EURESCOM Participants in Project P816-PF
  5. 5. Deliverable 3 Implementation Strategies therefore interesting cellular applications for HFR. The EURESCOM P921 Project UMTS has shown that signals can be transmitted successfully using different analogue optical feeders. Cellular HFR can offer a future-proof network architecture, as there will be a lot of commonality between 2G and 3G systems from an architectural point of view. In 2G systems a mature micro-cellular and pico-cellular technology is already realised. However, in some cases it is an advantage to have the digital signal processing as close as possible to the antenna, and HFR may not be the best choice. Examples are places suffering strong interference from other cells or if using antenna arrays for diversity reception. For indoor application like WLANs, which are at the low end in terms of potential operator revenue, it may be difficult to get access to the privately owned fibre infrastructure. On the other hand, this could provide an opportunity to ensure indoor penetration for public systems like GSM and UMTS using HFR. For wireless systems working at frequencies above 10GHz, like LMDS, the use of HFR within the next 5 years is questionable, as commercial analogue optical feeders are not available yet. Intermediate radio frequency transmission. e.g. at around 1GHz, using commercial HFR equipment and frequency up- and down conversion at the RAU, may be used in the mean time to centralise radio equipment. The topology can be star, tree, bus or a mixture of these. In the star topology each RAU (every transceiver in the base station) is connected via independent fibre pairs. Active RAUs are assumed, hence powering must be provided. This scenario requires the highest volume of fibre. WDM technology (λ = 1.3/1.55µm) may be used to half the fibre count. Although DWDM technology makes the best usage of the huge bandwidth of the optical fibre and can be also used for more complex topologies like bus or tree, it is currently seen as too expensive for the access network market. Single Mode Fibre (SMF) is recommended for HFR implementation, because the dispersion penalties are low for fibre lengths up to 20km and radio frequencies below 20GHz. Multimode and plastic fibre may be also used for indoor applications, as costs are cheaper. However, the usable fibre length for multimode and plastic fibre will be below ~1 km and ~100 metre respectively, for fRadio < 5GHz HFR technologies have been compared in terms of economics for different radio systems by including maintenance costs, site rental, site acquisition and power supply costs. The study has been done looking at the next 5/10 years from today’s perspective and the technologies have been compared against a digital base band HFR implementation. The installation costs and revenues have not been considered in this study. The main results obtained from the techno – economical evaluation include: • Non-base band HFR technology can cost in for the above listed wireless systems (with the exception of ‘Wireless LANs’), based on reduced site costs and increased reliability. • The passive EAM-based solutions can yield the lowest complexity at the RAU, but due to the short range the main application will be for indoor room-cell applications. • The important factors are associated with architectural rather than technological differences in the feeders Future economic studies will therefore need to consider the following points © 2000 EURESCOM Participants in Project P816-PF page iii (ix)
  6. 6. Implementation Strategies Deliverable 3 • the number of BS which have to be centralised • the consideration of multiple radio transmission to the same RAU, e.g. for the indoor environment in order to become cost efficient • the simultaneous transmission of analogue and digital signals over the same fibre In summary, current HFR implementations can be found in public/industrial places like airports, sport stadiums, mines, subways, etc.. , However, until now there are only a couple of commercial HFR equipment suppliers on the market. In the next 5 years HFR may find a larger market in the indoor picocell and outdoor microcell wireless networks, as it allows operators to upgrade their systems smoothly from current 2G systems to 2.5G and 3G systems. For the implementation of HFR guidelines have been worked out considering: (1) radio aspects, (2) optical feeder technologies, (3) type of fibre, (4) radio cell size and (5) optical architecture. New base station design concepts are needed in order to make use of the full economical benefits of centralised base stations by allowing dynamic channel allocation between all cells served by the centralised head end. page iv (ix) © 2000 EURESCOM Participants in Project P816-PF
  7. 7. Deliverable 3 Implementation Strategies List of Authors Antti Siitonen AF Seppo Parkkila AF Dave Wake BT Steve Buttery BT Sen Lin Zhang BT Mihai Mateescu DT Ralf Schuh DT Andrea Bausz HT Balazs Kiacz HT Mauritz Lahti ST Milan Jankovic YU Borislav Odadzic YU © 2000 EURESCOM Participants in Project P816-PF page v (ix)
  8. 8. Implementation Strategies Deliverable 3 Table of Contents PREFACE....................................................................................................................................I EXECUTIVE SUMMARY.......................................................................................................II LIST OF AUTHORS.................................................................................................................V TABLE OF CONTENTS.........................................................................................................VI ABBREVIATIONS...............................................................................................................VIII INTRODUCTION.......................................................................................................................1 1 SCENARIOS FOR THE INTRODUCTION OF INTEGRATED WIRELESS OPTICAL NETWORK ACCESS.............................................................................................2 1.1 STUDY OF HFR INTRODUCTION IN EXISTING AND PLANNED NETWORKS............................................2 1.2 EVALUATION OF INTRODUCTION SCENARIOS .................................................................................5 1.3 COMPARISON OF HFR VERSUS HFC AND OPTICAL ACCESS...........................................................6 1.3.1 Comparison of service characteristics of HFR versus HFC and optical access.........6 1.3.2 Service comparison......................................................................................................6 2 DEPLOYMENT AND IMPLEMENTATION CONSIDERATION FOR HFR-BASED SYSTEMS....................................................................................................................................9 2.1 KEY DEPLOYMENT CRITERIA....................................................................................................9 2.2 CANDIDATE HFR TECHNOLOGIES..............................................................................................9 2.3 CANDIDATE APPLICATIONS.....................................................................................................13 2.3.1 High Speed Wireless LAN: .......................................................................................14 2.3.2 UMTS Urban Microcellular Network:......................................................................15 2.3.3 GSM/DCS1800 Suburban Macrocellular Network...................................................15 2.3.4 LMDS.........................................................................................................................16 2.4 ASSESSING TECHNOLOGIES AGAINST APPLICATIONS......................................................................16 3 COMPARATIVE COSTINGS FOR HFR SYSTEMS.......................................................17 3.1 THE DEFINITION OF THE MODEL................................................................................................17 3.2 THE WIRELESS ARCHITECTURES CONSIDERED..............................................................................18 4 FREQUENCY SURVEY AND REGULATORY BACKGROUND.................................21 4.1 ORGANISATIONS RESPONSIBLE FOR FREQUENCY MANAGEMENT IN EUROPE.......................................21 4.2 EUROPEAN FREQUENCY CO-ORDINATION....................................................................................22 4.2.1 Long term planning: DSI...........................................................................................22 4.2.2 Frequency survey ......................................................................................................22 4.3 REGULATORY BACKGROUND....................................................................................................24 5 FEASIBILITY OF TECHNICAL SCENARIOS................................................................26 5.1 HFR ACCESS FOR DIFFERENT RADIO SYSTEMS............................................................................27 6 MANUFACTURE SURVEY................................................................................................30 6.1 HFR PRODUCT INFORMATION..................................................................................................30 6.2 CURRENT PRICES FOR HFR FEEDERS........................................................................................34 7 RECOMMENDATIONS FOR OPERATORS...................................................................35 7.1 CURRENT EMPLOYMENT OF HFR.............................................................................................35 7.2 HFR EMPLOYMENT IN THE NEAR FUTURE (< 4 YEARS)...............................................................35 7.3 HFR EMPLOYMENT IN THE FAR FUTURE (> 4 YEARS)..................................................................37 page vi (ix) © 2000 EURESCOM Participants in Project P816-PF
  9. 9. Deliverable 3 Implementation Strategies 7.4 IMPLEMENTATION GUIDELINES..................................................................................................38 © 2000 EURESCOM Participants in Project P816-PF page vii (ix)
  10. 10. Implementation Strategies Deliverable 3 Abbreviations 1G, 2G, 3G 1,2,3 Generation B/N-ISDN Broadband/Narrowband-ISDN BS Base Station BSC Base Station Controller BTS Base Transceiver Station BW Bandwidth CDMA Code Division Multiple Access CEPT European Conference of Postal and Telecommunications Administrations CO Central Office CPEAM Centrally Powered EAM DCA Dynamic Channel Allocation DCS Digital Cellular System DECT Digital Enhanced/European Cordless Telecommunication DFB Distributed Feedback laser DR Dynamic Range DSF Dispersion Shifted Fibre DS-FDD Discrete Sequence-FDD DWDM Dense Wavelength Division Multiplexing EAM Electroabsorption Modulator EDGE Enhanced Data rates for GSM Evolution EN External Network functional grouping ERC European Radiocommunications Committee ERO European Radiocommunications Office ETSI European Telecommunications Standards Institute FDD Frequency Division Duplex FOR Fibre Optic Repeater FTTB Fibre To The Base FTTC Fibre To The Curb FTTH Fibre To The Home GSM Global System for Mobile Communication HFC Hybrid Fibre Coax HFR Hybrid Fibre Radio HIPERACCESS High Performance Radio ACCESS page viii (ix) © 2000 EURESCOM Participants in Project P816-PF
  11. 11. Deliverable 3 Implementation Strategies HIPERLAN High Performance Radio LAN IF Intermediate Frequency IS-95 Industry Standard - 95, CDMA-based cellular phone standard ISDN Integrated Service Digital Network ITU-T/R International Telecommunication Union – Radio communication Sector/ Telecommunication Standardisation Sector LAN Local Area Network LMDS Local Microwave Distribution System LNA Low Noise Amplifier LPEAM Locally Powered EAM LT Line Termination MBS Mobile Broadband System MMDS Multipoint Microwave Distribution System MSC Mobile services Switching Centre MTBF Mean Time Between Failure MWS Multimedia Wireless Systems NPV Net Present Value NT Network Termination OSSB Optical Single Side Band PA Power Amplifier PCS Personal Communication System PEAM Passive EAM POTS Plain Old Telephony Service PSTN Public Switched Telephone Network QoS Quality of Service RAU Remote Antenna Unit RF Radio Frequency SCMA Sub Carrier Multiplex Access SMF Single Mode Fibre S-UMTS Satellite-UMTS interface TEF Terminal Equipment Functional grouping, TDD Time Division Duplex UMTS Universal Mobile Telecommunication System VDSL Very-high-speed-Digital Subscriber Line VoD Video on Demand WCDMA Wideband CDMA © 2000 EURESCOM Participants in Project P816-PF page ix (ix)
  12. 12. Implementation Strategies Deliverable 3 WDM Wavelength Division Multiplexing WLAN Wireless-LAN WLL Wireless Local Loop WRC World Radio Conference page x (ix) © 2000 EURESCOM Participants in Project P816-PF
  13. 13. Deliverable 3 Implementation Strategies Introduction In Task 2 of the P816 project (see Deliverable D1) different analogue optical feeder technologies and their usage for transmitting a variation of existing and future radio standards are discussed. The D1 report gives a detailed theoretical background by dealing with the performance parameters of such analogue optical feeders. In this deliverable the focus is on the implementation and integration of such feeders in current and future wireless systems. Questions which will be answered within this report are: • Which optical feeder for which radio system • How does HFR compare with other access technologies like HFC or fibre to the home • Frequency issues when implementing different radio systems • Which architecture should be used • What are the economical benefits • Implementation guidelines for operators The deliverable also contains a detailed study of commercial HFR systems from different manufacturers. The implementation, architectures and prices of these systems are evaluated. © 2000 EURESCOM Participants in Project P816-PF page 1 (41)
  14. 14. Implementation Strategies Deliverable 3 1 Scenarios for the introduction of integrated wireless optical network access 1.1 Study of HFR introduction in existing and planned networks In wireless networks optical transmission can be used in the following areas: (a) Transmission between the switch (LE or MSC) and the base station controllers (if they are not co-located); (b) Transmission between the BSC and the BTSs (if they are not co-located); (c) Transmission between the BTS and the RAU. The points mentioned in (a) and (b) are in order to provide a complete survey. They realise a “hybrid access” configuration, where fibre and radio are applied as independent technologies. Fibre is deployed in the feeder part using digital base band transmission, and radio is used in the distribution and drop segments of the access network. This is already a real-life scenario. It is attractive since it can utilise the existing fibre infrastructure. A disadvantage may be that the existing feeder plan makes some constraints on the radio plans so optimised coverage planning is not in the forefront. Case (c) describes the HFR solution which is also the main focus within this report. The radio signals of the base station are transmitted to remote antenna units via optical fibre. One of the main advantages of HFR is the ability of shifting radio specific functionality from the BTS to some centralised point, e.g. the central office (CO). This allows a central wireless control of the access network. HFR may be integrated in different current/future radio systems: • Fixed wireless access: WLL, HIPERACCESS, LMDS and MMDS systems. • Cellular systems like GSM-900, DCS-1800, IS-95, WCDMA, etc. • Indoor WLANs: Hiperlan 2, IEEE802.11(a). • Satellite access systems The report focuses on the following HFR technologies (see D1 for more detail): • Baseband digital • Analogue direct-modulation direct-detection (e.g. DFB and PIN diode), fradio ~< 10GHz • Electro absorption modulator (EAM) – transceiver (passive, centrally or locally powered), fradio ~< 10GHz • mm-wave optical feeders, e.g. optical single side band (OSSB) ,10GHz ~< fradio ~< 100GHz Figure 1 shows the two basic principals of the optically embedded radio feeders, namely baseband and analogue. page 2 (41) © 2000 EURESCOM Participants in Project P816-PF
  15. 15. Deliverable 3 Implementation Strategies Centralised Office Remote Antenna Unit (a) Baseband (BB) feeder E O BB Service Node NT O E RF (b) Analogue optical feeder BB E O Service Node NT E RF O NT: network termination Figure 1 HFR baseband feeder and analogue feeder Beside shifting base station complexity to a centrally controlled location in order to reduce maintenance costs and the possibility to allow dynamic channel allocations, HFR has the goals: • to transmit as many as possible radio services over the same fibre to some remote antenna site, in order to utilise the full spectrum of the optical fibre • to allow simple upgrade to further upcoming radio standards, e.g. from GSM to UMTS However, there are some restrictions given by the optical feeders as: maximum radio frequency, maximum fibre length, dynamic range (DR), etc. This makes it necessary to choose the proper optical feeder design right from the start of implementation. A very important economical point for HFR introduction in planned networks is the existing fibre infrastructure. In P816 Task 4 some assumptions have been taken for the availability of ducts / optical fibre access points in different areas , see Table 1. Area # of Distance Area type Access Area Parameters radius access among access [km] areas areas [km] Radius Living unit Duct avail. Bus/Res [km] density ratio Downtown 1 9400 80% 1 1 0 Urban 1.5 2400 60% 2.7 4 0.4 Rural 1.5 80 10% 10.0 9 3 Table 1Area type segmentation, from P816 Task 4 From Table 1 we can see that the number of fibre access points in downtown areas can be quite high, which is promising for HFR implementation as this fibres may be used to carry the radio signals together with digital transmission. For indoor HFR access the case is slightly different as these are normally privately owned premises and even in the case of existing indoor fibre infrastructure (e.g. plastic fibre), operators maybe not easily allowed to use it for radio indoor coverage. WDM access networks: An increasing number of European telecom operators are currently performing trials using DWDM technology, in order to overcome capacity bottlenecks and to use passive optical routing. Relatively high insertion loss and prices are currently some of the main drawbacks for full DWDM implementation. However, © 2000 EURESCOM Participants in Project P816-PF page 3 (41)
  16. 16. Implementation Strategies Deliverable 3 the insertion loss may be as low as 3 dB in the future, and price can be expected to fall, as DWDM will be used as a standard technology to extend transmission capacity. In the case of HFR different optical wavelengths may be used to carry different radio services over the same fibre to some remote located antenna unit. Moreover, WDM or DWDM would allow a passive bus or tree network architecture. But as currently DWDM components prices and insertion losses are to high, HFR access with star architecture seems more reasonable, which implies that there are at least two fibres for every transceiver at the CO. Figure 2 shows a possible outdoor HFR architecture for cellular systems with the base transceiver station (BTS) and base station controller (BSC) at a centralised location. As 2G and 3G cellular systems are working below 10GHz analogue feeders using direct-modulation and direct-detection can be used. The fibre length in order to avoid dispersion penalties should be below ~20km. Different architectures for the above shown scenario are possible, depending if using one wavelength or WDM / DWDM technology. 1. In the case if using one wavelength (e.g. at 1.55µm) for the down and up-link two fibre pairs are necessary for every transceiver (radio channel / radio service). As every RAU needs its own fibre pair from the CO, the access network could be a star architecture. 2. If using WDM technology one fibre would be sufficient per transceiver. For the down-link we may transmit at λ = 1.55 µm and for the up-link at λ =1.3 µm. 3. The use of DWDM is the most novel one as it can provide different services over just one fibre. In the case of sectorisation this may be used to differentiate the signal in the fibre between the sectors. Similar architectures we could draw for fixed wireless access (e.g. LMDS) or indoor HFR access (e.g. WLANs), as the main difference beside the radio cell size would be in the actual optical feeder and this is not shown explicitly in the figure above. λ to 8 5 , fS,6 to 10 λ , fS,2 2 S ate llite a cces s λ , fS ,1 1 Couple r Ce ntra l Office fR,1 fS ,1 λ1 WDM λ Loca l BS x couple rs , fS,5 to 7 s e rve r fS ,n λ fR,n n S witching Ra dio RF/IF to Optic Ce ntre Units Inte rfa ce λ , fS ,1 x λ , fS,2 x Core 2 fibre s Ne twork λ 1 to 3 Figure 2 HFR access system for current and future cellular systems page 4 (41) © 2000 EURESCOM Participants in Project P816-PF
  17. 17. Deliverable 3 Implementation Strategies 1.2 Evaluation of introduction scenarios The introduction of HFR is mainly interesting in the micro- and picocell domain as output power and DR of the optical feeders are limited (at least for the feeders with low complexity). The saving of maintenance cost, as will be seen in the following sections, is on of the most driving forces for HFR implementations. Therefore the number of BSs which can be centralised in such relatively small cells is an important question. For the successful introduction of HFR in the different wireless domains different points have to be considered. Cellular mobile networks are generally categorised as 1st, 2nd and 3rd generation systems. 1st generation (analogue) systems are loosing market share and will be closed within 4-10 years. 3rd generation has too much uncertainty for the time being and will not be widely used before ~2003. For HFR evaluation 2G (2.5G) systems like GSM, IS-95, EDGE, IS-136HS. are the most interesting at the moment. Some of the pros and cons for cellular HFR are: + Future proof network architecture, as there will be a lot of commonality between 2nd and 3rd generation systems from an architectural point of view, and matured micro-cellular and pico-cellular technology is already realised. + 2G and 3G cellular systems are working below 10GHz and commercial analogue optical feeders are existing. - In 2nd generation mobile systems the majority of radio resource management tasks are performed in the BSC which is a major change and achievement compared to 1st generation systems. As systems develop, more and more tasks will be removed from the mobile services switching centre (MSC) to meet the challenges coming from the market pressure for new services. Therefore the idea of centralising the radio management for the sake of cutting costs in the base station network using optical fibre is against the main trends, unless the size of the actual network served by the HFR network is limited. - In places with strong interference from other cells or if antenna arrays for diversity reception is used, it is from advantage to have the digital signal processing as close as possible to the antenna. It should be also noted that dynamic channel allocation (DCA) with its obvious advantages, contributes to operator differentiation along with pricing and services. For indoor application like WLANs which are at the low end market operators may find it any case difficult to get access to the privately owned fibre infrastructure. On the other hand if employed this could provide an opportunity to ensure indoor penetration for public systems like GSM and UMTS. As multimode or plastic fibre may be the preferred medium for indoor cabling, the optical analogue feeders must be able to adapt to this requirement. The maximum usable fibre lengths for multimode fibre will be around 1 km. For wireless services working above 10GHz like LMDS and having radio coverage >> 1km (e.g. MVDS) the use of HFR within the next 5 years is questionable, as commercial analogue optical feeders are not available yet and huge cell sizes (>>10km) does not give very much need for centralisation. For smaller cells (e.g. LMDS in suburban areas) an intermediate radio frequency transmission. e.g. at around 1GHz, using commercial HFR equipment and frequency up- and down conversion at the RAU may be used. © 2000 EURESCOM Participants in Project P816-PF page 5 (41)
  18. 18. Implementation Strategies Deliverable 3 The architecture may be star, tree, bus or a mixture of these architectures. In the star architecture each RAU (every transceiver in the base station) is connected via independent fibre pairs. Active RAUs are assumed, so powering must be provided. This scenario requires high volume of fibres. WDM technology may be used to half the fibre count. Although DWDM technology can be used to further reduce the fibre count and could be used for more complex architecture like bus or tree architectures, it is currently seen as to expensive for the access network. 1.3 Comparison of HFR versus HFC and optical access 1.3.1 Comparison of service characteristics of HFR versus HFC and optical access Studying the service characteristics, the most important difference between HFR, HFC and fibre access is the available bandwidth, which defines the set of supported services. Radio systems are optimised to support a pre-defined set of services within a given “limited” bandwidth. For the optical access the following cases are covered: fibre-to-the-home (FTTH) and fibre-to-the-curb (FTTC) with very-high-speed-digital subscriber line to the home (VDSL). Some of the fundamental difference between available bandwidth of HFR, HFC and the optical accesses are: t In HFR networks the applied radio technology forms the bottle-neck of the system regarding bandwidth and quality issues. For HFR factors like customer density matters for the available bandwidth per user. Ë HFC, as an integrated broadband multi-service system, is able to offer large bandwidth for the user especially in the downstream, however it has limitations on the reverse path. s For the FTTH case, there are in practice no limitations on the bandwidth that can be offered to the customer. The bandwidth offered by a FTTC/B system will in most cases be higher than for a HFR case. t In case of fixed wireless access systems terminal installation and power supply will be an issue at the customer premises, and battery backup may be required as well. Ë For HFC, power supply and backup is solved at the optical node, from where the coaxial cable can carry power to the customer premises. s Fibre access like HFR requires the provision of local power at the customer premises due to the lack of metallic access lines for powering from the access node. From the installation point of view HFR has the advantage of fast implementation, however factors as: aerial alignment and new cabling between the outdoor and indoor units have to be considered. It should be noted that a HFC network can be used to connect BTSs to the BSC. 1.3.2 Service comparison Both HFC and HFR are in the early phase of standardisation. Currently, service capabilities and characteristics depend on proprietary solutions to a great extent. Therefore any comparison of HFC and HFR systems can only be based on information available from manufacturers. Unfortunately, this information cannot be considered as consistent and the comparison can be made at a general level only. page 6 (41) © 2000 EURESCOM Participants in Project P816-PF
  19. 19. Deliverable 3 Implementation Strategies Distribution services are uni-directional services, where no return channel is required. t For most of the radio technologies the bandwidth requirement are excessive, which makes fixed wireless systems such as MMDS/MVDS (called also “wireless CATV”) and LMDS the only real radio alternatives suitable for this service. HFR has the advantage of providing the broadcast functionality inherently in the access medium. Ë CATV systems based on HFC traditionally provided analogue distribution services: analogue television and analogue audio. In addition modern HFC systems can support digital broadcast services as digital television, digital audio and broadcast data as well. s CATV is essentially a one-way broadcast service. For FTTH, broadcast functionality must be provided separately resulting in additional cost. For FTTC/B, the limited bandwidth available in the VDSL path makes real CATV emulation impossible. Telephone service (switched narrowband services) cover POTS, ISDN and n*64kb/s services. t HFR systems based on broadband systems like LMDS are able to provide high quality telephony services. Data rates of B-ISDN, E1 and E3 are usually available. However, it should be noted that the primary purpose of these systems is to provide higher data rates and multimedia services. HFR systems based on cellular and cordless radio standards, which were basically developed for telephony purposes, provide POTS/ISDN services. The main differentiator for HFR is the ability to provide mobility. Due to the mobile nature of these systems quality of service issues like latency and loss requirements are different from wireline networks. Mobile systems have a slower connection set up phase because of authentication and mobility management matters and a higher transmission delay due to speech coding and other radio related issues. Since quality aspects are affected by the radio path as well, proper radio planning is essential to ensure the possible best performance of the system. Ë In HFC networks cable telephony may be an independent technical sub-system. At the customer premises subscribers are provided with cable telephone terminals which connect the traditional terminals - telephone, PBX, fax and modem to the network. Since in HFC systems the upstream bandwidth is a limit, careful engineering is needed to plan the network for the return path, as the dial tone must be available with the usual POTS probability for each subscriber. An other important issue is to improve reliability, especially for those CATV operators, who upgraded their earlier CATV network to provide telephony services as well. While loss of video service is just an inconvenience for the user, loss of telephone service can be threatening to life. Therefore service availability must be in line with POTS/ISDN requirements. s Fibre access in general provides superior performance with very low bit error rate and transit delay. Asymmetric broadband services like video on demand or internet access, which can require huge downstream bandwidth: t In HFR systems LMDS is able to provide VoD. HFR based on LMDS supports client/server communication with dedicated or shared capacity. LMDS usually © 2000 EURESCOM Participants in Project P816-PF page 7 (41)
  20. 20. Implementation Strategies Deliverable 3 provides the capacity of 1 Gbit/s per sector. The supplied rates are 10 Mbit/s-55 Mbit/s per customer in the downstream and 64 kbit/s- 40 Mbit/s (primarily 1-2 Mbit/s) per customer in the upstream. HFR based systems are also suitable to provide Internet access. The available bit- rate depends on the radio technology. HFR based on mobile technologies may provide mobility, which will be an important issue for Internet access in the future. Emerging mobile standards will support asymmetric traffic as well. Ë HFC network can serve as a platform for high speed data services. In HFC systems within the bandwidth of a TV channel the downstream traffic is about 10-30 Mbit/s, the upstream is up to 2, 5 Mbit/s. However, both directions are shared by the active users connected to the same optical node. The available bandwidth per user depends on the number of active modems and on the limitation, which can be set by the service provider. During the peak period a typical example is 100 kbit/s in downstream and 10 kbit/s in the upstream for one user; off-peak values can be an order of magnitude higher. s Video on Demand service providing individual video streams for all active customers requires extreme bandwidths. This is a service well suited for FTTH. For FTTC/B the limited bandwidth will be in the VDSL section, and puts some constraints on the total number of simultaneous video on demand streams on a single physical pair. Symmetric broadband services cover digital services, which need the same high bit rate both for downstream and upstream traffic. Typical examples are point-to-point connections for dedicated subscribers, such as high quality video phone, video conferencing and LAN-interconnection. Both HFC and HFR are in general able to carry such traffic. For the interconnection of two or more LAN segments, FTTH provides the advantages of higher potential bandwidth and better QoS parameters. Mobility support, which is a key characteristic of HFR, is of minor value for this service. From the above we can conclude: • HFR provides mobility support • HFR can inherently support broadcast services • HFR requires no new cabling / ducting to individual customers but on the other hand • HFR has limited bandwidth due to radio frequency allocation issues • HFR requires local powering at the customer premises equipment • HFR is less suited than HFC/FTTH for video on demand type of services page 8 (41) © 2000 EURESCOM Participants in Project P816-PF
  21. 21. Deliverable 3 Implementation Strategies 2 Deployment and implementation consideration for HFR-based systems 2.1 Key Deployment Criteria When deploying radio access systems, there are a number of parameters to be considered. These are introduced and discussed below: Frequency Range: Some HFR technologies impose restrictions on the range of frequencies that can practically be supported. In turn, this may impose restrictions on how certain radio signals are carried over a particular technology. Bandwidth and/or Capacity: HFR technologies will impose some restriction on the bandwidth of the signals that they can carry. This limitation can either take effect at radio frequencies (i.e. RF or IF bandwidth) or at baseband (in terms of capacity, expressed in terms of bit/s). However, all of the HFR technologies considered here can be designed to be broadband. In this case the HFR technologies will not have an impact on the bandwidth or capacity of the radio system. Radio System Gain: In practical terms, some HFR technologies will introduce limits in terms of receiver sensitivity and/or transmit power of the radio elements of the system. The combined impact of these can be expressed as Radio System Gain (i.e. the path loss that can be tolerated by the system whilst delivering the specified level of performance). It is clear, therefore, that, for any given application/technology combination, the attainable radio cell size will be strongly linked to Radio System Gain. Dynamic Range: Like System Gain, the dynamic range of an HFR technology can also impose limits on the cell size attainable for a given service. Availability: The technology options considered within this report range from the well established to the state-of-the-art. Obviously, this is an important aspect of any technology as it defines the time scales within which it can be deployed ‘in anger’. It should be noted, however, that the impact that this has on cost will not be considered here, as such economic issues will be considered in the D2 report. Flexibility: The term ‘flexibility’ covers several different system aspects, including the ability to support different architectures, applications and services. Complexity: Complexity has an impact on a number of system behaviours, including cost and reliability. The location of a system’s most complex items is also important – a system with single complex ‘Controller’ is an entirely different proposition to a system with numerous complex base stations, even if the overall level of system complexity is equivalent. Reliability: The reliability of a technology is a key factor in determining its current account costs. Whilst the detailed economic impact of this will be covered in the D2 report, a broad indication of the reliability of the key component of each technology will be given here. 2.2 Candidate HFR Technologies This section draws and extends from the results of the D1 report. Six technology options have been chosen for this study based on one or more of the following principles: © 2000 EURESCOM Participants in Project P816-PF page 9 (41)
  22. 22. Implementation Strategies Deliverable 3 • wide range of technologies for purposes of comparison • high performance compared to similar alternatives • interesting and novel Each technology is assessed based on its most suitable and effective frequency range, the maximum cell size or radio range it supports, its relative complexity, component availability and the flexibility it offers in terms of system architecture, the results are summarised in Table 2. Figure 3 shows the generic reference configuration. Radio TEF NT link LT1 LT2 EN TEF – Terminal Equipment Functional grouping, NT – Network Termination functional grouping LT1 – Line Termination 1 functional grouping, LT2 – Line Termination 2 functional grouping EN – External Network functional grouping Figure 3 Generic Reference Configuration Baseband Digital: The transmission system consists of a baseband digital optical fibre link to a remote antenna unit (RAU) where the signal is detected, amplified, demultiplexed, remodulated and up-converted to the radio carrier frequency. TEF NT LT1 LT2 EN Radio link antenna laser/photodiode pair PA/LNA + diplexer optoelectronic control upconverter/downconverter amplifiers modulator/demodulator network interfacing multiplexer/demultiplexer power supply laser/photodiode pair optoelectronic control power supply Figure 4 Baseband Digital Mapped onto Generic Reference Configuration Analogue direct-modulation with direct-detection (DFB-PIN diode): The transmission system consists of a subcarrier analogue optical fibre link to a remote antenna unit (RAU) where the signal is detected and amplified. Up-conversion to the radio carrier frequency takes place only in the case of intermediate frequency (IF) transmission over the optical link (see below). The e/o conversion function is performed by direct modulation of a microwave distributed feedback (DFB) laser. TEF NT LT1 LT2 EN Radio Link antenna laser/photodiode pair PA/LNA + diplexer optoelectronic control laser/photodiode pair upconverter/downconverter optoelectronic control modulator/demodulator power supply multiplexer/demultiplexer amplifiers network interfacing power supply Figure 5 Analogue DFB-PIN Mapped onto Generic Reference Configuration page 10 (41) © 2000 EURESCOM Participants in Project P816-PF
  23. 23. Deliverable 3 Implementation Strategies mm-wave optical feeder: OSSB is a technique developed to avoid dispersion problems in mm-wave optical links (direct transmission of the mm-wave radio carrier). The most practical realisation of this technique uses an external modulator, driven in such a way that one of the two conventional modulation sidebands is suppressed. Dispersion is therefore removed as a limiting factor in determining the maximum carrier frequency. TEF NT LT1 LT2 EN Radio Link antenna laser/photodiode pair PA/LNA + diplexer optical modulator downconverter optoelectronic control laser/photodiode pair upconverter optoelectronic control modulator/demodulator power supply multiplexer/demultiplexer amplifiers network interfacing power supply Figure 6 Optical Single Sideband Mapped onto Generic Reference Configuration Passive EAM Transceiver: An EAM is used as an unpowered transceiver in the RAU. It acts as a photodetector for downstream signals and as a modulator in the upstream direction. It replaces a laser-photodiode pair in a conventional analogue link and as a consequence also removes the need for laser control circuitry. No amplification or power supplies are used to achieve the ultimate in RAU simplicity. TEF NT LT1 LT2 EN Radio Link antenna laser/photodiode pair EAM transceiver optoelectronic control upconverter/downconverter modulator/demodulator multiplexer/demultiplexer amplifiers network interfacing power supply Figure 7 Passive EAM Transceiver Mapped onto Generic Reference Configuration Centrally Powered EAM Transceiver: This uses an EAM as a transceiver in the RAU but uses a power supply to provide power for biasing the EAM and for a limited amount of amplification. The power supply is centrally located and delivered to the RAU using a hybrid (fibre and copper) cable. The power requirements are kept sufficiently low that the maximum practical cable length and the cable flexibility are not constrained by the additional copper. © 2000 EURESCOM Participants in Project P816-PF page 11 (41)
  24. 24. Implementation Strategies Deliverable 3 TEF NT LT1 LT2 EN Radio Link antenna laser/photodiode pair EAM transceiver optoelectronic control PA/LNA + diplexer upconverter/downconverter passive voltage control modulator/demodulator multiplexer/demultiplexer amplifiers network interfacing power supply Figure 8 Centrally Powered EAM Transceiver Mapped onto Generic Reference Configuration Locally Powered EAM Transceiver: Again, this technology makes use of an EAM transceiver in the RAU. The amplifier gain is not constrained and the RAU is powered from a local mains supply. Technology Frequency Bandwidth/ System Gain Dynamic Availability Range Capacity Range Baseband All frequency Not limited by Not limited by Not limited by Readily available Digital bands. optical optical optical from many sources. technology. technology. technology. Analogue Microwave Not limited by Not limited by 120 dB Available from DFB-PIN (0.1– 10GHz) optical optical several sources, but technology. technology. (1 Hz) not as widely as No limit for digital. IF link. Optical Single mm-wave Not limited by Not limited by 110 dB Not commercially Sideband (20- 70GHz) optical optical available. technology. technology. (1 Hz) Passive EAM Microwave Not limited by Limited (e.g. by – 110 dB Not commercially Transceiver (0.1 – 10GHz) optical 15 dBm tx. Power available. technology. at RAU antenna) (1 Hz) Centrally Microwave Not limited by Limited. Will be 120 dB Not commercially Powered (0.1 – 10GHz) optical (e.g. 20 dB) available. EAM technology. greater than for (1 Hz) Transceiver passive EAMs. Locally Microwave Not limited by Not limited by 120 dB Not commercially Powered (0.1 – 10GHz) optical optical available. EAM technology. technology. (1 Hz) Transceiver No limit for IF link. page 12 (41) © 2000 EURESCOM Participants in Project P816-PF
  25. 25. Deliverable 3 Implementation Strategies Technology Flexibility RAU Complexity Reliability Baseband Low. The air High. Contains large Low. Equipment exposed to harsh Digital interface and cell amount of signal processing environment at remote BS, power capacity cannot be and frequency translation supply at remote BS decreases changed dynamically. electronics. reliability. Analogue DFB- High. Centralisation Low. No signal processing Better than BB but still Low. PIN of resources means required. Frequency Less equipment exposed to harsh simple upgrading and translation only required for environment at remote BS, power reconfiguring. IF link. supply needed at remote BS. Optical Single High (due to Low. No signal processing Better than BB but still low. Less Sideband centralisation) or frequency translation equipment exposed to harsh required. environment at remote BS, power supply needed at remote BS. Passive EAM High (due to Extremely low. No High. Much less equipment Transceiver centralisation) electronics or power supply exposed to harsh environment at required. remote BS, power supply not needed at remote BS. Centrally High (due to Very low. No signal Medium. Less equipment exposed Powered EAM centralisation) processing, frequency to harsh environment at remote Transceiver translation or local power BS, central power supply is more supply required. reliable than local power supply at remote BS. Locally High (due to Low. No signal processing Medium or low. Less equipment Powered EAM centralisation) required. Frequency exposed to harsh environment at Transceiver translation only required for remote BS, power supply needed IF link. at remote BS. Table 2 Summary of candidate technologies TEF NT LT1 LT2 EN Radio Link antenna laser/photodiode pair EAM transceiver optoelectronic control PA/LNA + diplexer upconverter/downconverter power supply modulator/demodulator multiplexer/demultiplexer amplifiers network interfacing power supply Figure 9 Locally Powered EAM Transceiver Mapped onto Generic Reference Configuration 2.3 Candidate Applications There are many applications that can be addressed using HFR technologies. In order to ensure a logical approach to this potentially vast area of work, a logical breakdown of the ‘Problem Space’ is required. In an example, Figure 10 defines a rural telephony (Wireless Local Loop – WLL) service as having the following characteristics: © 2000 EURESCOM Participants in Project P816-PF page 13 (41)
  26. 26. Implementation Strategies Deliverable 3 Environment Indoor Urban Suburban Rural Network Type Public Private Bandwidth Broadband Midband Narrowband Symmetry Symmetric Asymmetric Broadcast Mobility Fixed Low Mobility High Mobility Rural Telephony (WLL) Figure 10 Definition of a Rural Telephony (WLL) Service The following criteria were used to select the candidate applications: • Business Need: There is little point in analysing applications that are unlikely to be required in the short to medium term. • Diversity: The three applications were chosen to be different enough to allow the relative merits of the short-listed technologies to be fully examined • Fit with Project Scope: The applications were chosen to fit well within the overall scope of the project. As a result of this, the following applications were selected: 2.3.1 High Speed Wireless LAN: The mapping between the physical and functional groupings of the generic reference model for WLAN is shown in Figure 11. WLAN WLAN WLAN Switch or IP- Server Terminal Terminal Access router network Adapter Point Radio Interface Ethernet TCP/IP TCP/IP UDP/IP UDP/IP Figure 11 Wireless LAN Reference Model A wireless LAN application may be characterised in the following way: indoor private broadband symmetric low mobility Note that, in the context of this study, symmetry refers to the ultimate capacity of each direction of transmission, rather than its instantaneous behaviour. Thus, although the majority of sessions carried by a wireless LAN will be asymmetric, here it is classed as symmetric because the maximum obtainable ‘mobile to server’ bandwidth is typically the same as the maximum obtainable ‘server to mobile’ bandwidth. page 14 (41) © 2000 EURESCOM Participants in Project P816-PF
  27. 27. Deliverable 3 Implementation Strategies 2.3.2 UMTS Urban Microcellular Network: UMTS Core Terminal BTS BSC (MSC/GSN) TEF NT LT1 LT2 EN Figure 12 Mapping between functional and physical groupings for UMTS UMTS urban microcellular network may be characterised in the following way: urban public midband asymmetric low mobility The first two parameters are obviously correct. The last three, however, may be questioned: UMTS Bit Rates: It is likely that the maximum total user bandwidth for a UMTS microcell will be around 2 Mbit/s, with individual users unlikely to receive services in excess of 384 kbit/s. Thus, this is viewed as a midband application. UMTS Symmetry: Some UMTS applications, such as voice and video, will be predominately symmetric. However, many other applications will be highly asymmetric - mobile Internet users could, for example, have sessions with asymmetry ratios of several hundred to one (with the vast majority of the traffic being carried on the downlink). As this type of traffic is more likely to be prevalent in urban microcells (where people may be walking, standing and sitting) than macrocells (where many people will be driving), it is assumed here that UMTS microcell traffic will be asymmetric. Microcell Mobility: Some urban microcells may provide coverage to sections of road carrying reasonably fast moving traffic. However, this is unlikely to be the norm, and many urban microcells will only have to support pedestrian or very low terminal speeds. Consequently, for the purposes of this study, urban UMTS microcell traffic is viewed as having low mobility requirements. 2.3.3 GSM/DCS1800 Suburban Macrocellular Network DCS1800 Core Terminal BTS BSC (MSC/GSN) TEF NT LT1 LT2 EN Figure 13 Mapping between functional and physical groupings for GSM/DCS1800 A GSM/DCS suburban macrocellular network may be characterised in the following way: suburban public narrowband symmetric high mobility © 2000 EURESCOM Participants in Project P816-PF page 15 (41)
  28. 28. Implementation Strategies Deliverable 3 2.3.4 LMDS Base Station Local Customer Unit ATM Core Switch TEF NT LT1 LT2 EN Figure 14 Mapping between functional and physical groupings for LMDS A LMDS network may be defined in the following way: urban public broadband asymmetric/symm. fixed access 2.4 Assessing technologies against applications The technologies as introduced in section 2.2 (Candidate HFR technologies) have been assessed against the applications described in section 2.3. To enable a balanced assessment to be made, a numerical analysis has been used and the results are given in the table below. This work has been performed in the following way: 1. The relative importance of the features like listed in section 2.1 (low BS cost, high –reliability, –system gain. –frequency performance, –flexibility and –dynamic range) has been evaluated for each of the four applications. 2. The ability of each of the technologies to deliver the various features has been numerically evaluated. 3. The tables resulting from steps (1) and (2) have been combined and displayed in a single summary table, as given in the table. Technology Application BB DFB OSSB PEAM CPEAM LPEAM Wireless LANs UMTS Microcell DCS 1800 Suburban LMDS Table 3 Short-listed Technologies for the four Candidate Applications The ‘ticked’ shaded cells indicate the recommended application/technology pairing. The table indicates, not surprisingly, that there is no single ‘right’ choice of HFR technology. Instead, for any given application, there are two or three approaches that should be considered. It should be also mentioned that weighting has been used as some of the features dependence on the environment, e.g. low end or high end market, are more important then the others. page 16 (41) © 2000 EURESCOM Participants in Project P816-PF
  29. 29. Deliverable 3 Implementation Strategies 3 Comparative costings for HFR systems The technical considerations as discussed in section 2 (see Table 3) have been extended to include economical aspects like maintenance costs, site rental, site acquisition, power supply costs, etc. There are many different variants of HFR (see section 2 and 3) that can be used, and each one has its own distinct advantages and disadvantages. However, for any given application, there will typically be a single technology that will deliver the required functionality and offer the lowest whole life cost. The challenge for network operators is, therefore, to identify this ‘best’ technology for each of the applications that they wish to address. It should be noted at this point that in the given economical analysis there has been a large emphasis on the EAM technology and its suitability for HFR access. For this reason and as the EAM-based technologies under review are unlikely to be cost effective for another 5 years the analyses carried out has been done on a wide scope, with cost estimates done until and behind the year 2004. 3.1 The definition of the model Rather then showing here the actual procedures (spread sheets of counting for recurring and non-recurring expenditure) the assumptions made and the final results are given below. The full description may be found in the D2 report of P816. The technologies have been compared against a baseband HFR implementation as this is one way in which this application would be addressed today. From the identified HFR technologies as given in Table 3 the following ‘best case’ assumptions were made: • Cell Radius: All technologies are capable of delivering the target cell radius • Distribution Network: The cost of providing fibre is assumed to be no greater than the cost of providing copper LAN cables • Installation Costs: It is assumed that the installation costs of the HFR approaches were not increased by the need to terminate optical fibres (rather than simple twisted pair cables) There has been also done a more complex techno-economic evaluation in Task 4 P816 (see the D2 report) for various HFR techniques, by comparing them with other access methods. The key differences to the one reported here are: • This study does not consider revenues (i.e. it is a costing study rather than a business case analysis). This simplification is valid for this case because the revenues for each of the options will be identical as there is no difference in the services provided (rather just the way in which they are provided) • Simple costing models are used rather than the detailed database used elsewhere in Task 4. This is justified by the fact that the study focuses on what will be possible in 2004/2009, and it is therefore impossible to produce accurate detailed cost structures. • The outputs are expressed solely in terms of net present value (NPV). Payback period and internal rate of return analyses have been omitted. © 2000 EURESCOM Participants in Project P816-PF page 17 (41)
  30. 30. Implementation Strategies Deliverable 3 3.2 The wireless architectures considered For WLANs - HFR using passive and centrally powered EAM one of the key results found in the study is that there is no cost in (WLANs are 2 –3 times the cost of conventional solutions) as the primary benefit of HFR is the ability to centralise complex equipment, thereby reducing costs for environmental and process reasons. One of the reasons for this is that in the wireless LAN case, all equipment is indoors and easily accessible and the use of HFR is just adding complexity without any immediate benefits. Costings for Urban UMTS Microcells: (the costing have been compared against HFR baseband >5 years out from today) • The passive EAM approach showed up to be unsuitable due to its limited range, requiring more basestations to be installed • The powered EAM solutions showed up to cost half the price compared to the conventional baseband solution. The reason has been mainly the low site costs (i.e. ‘site acquisition’, ‘power supply preparation’, ‘site rental’ and ‘power supply ongoing’. This is logically correct, as the remote radio units will be very small and will require little or no power, but an operator’s ability to exploit this will be entirely dependent on their ability to set up commercial arrangements with site providers that reflect this. Costings for Suburban DCS1800 Macrocells: (the costing have been compared against HFR baseband >5 years out from today) • The direct-modulation with direct-detection (DFB-PIN diode) and locally powered EAM (LPEAM) based approaches both lead to considerably lower costs that the baseband digital solution. This difference is due to reduced site, power maintenance costs at the remote site – not any subtle technology differences. As the site and power costs are playing a key role in this scenario, and these are assumed to be the same for the DFB-PIN and LPEAM cases, there is no significant difference between the costs in both of these cases. Certainly, the differences shown are well within the ‘tolerances’ of this costing study, given the aggressive cost reductions assumed for optical components within an >5 year time frame. This is a very interesting result as it implies that what matters in this case is not the choice of HFR technology but the choice of overall architecture. Providing that the base station complexity can be centralised and the remote radio unit reduced in size and complexity, any suitable (non-baseband) HFR technology can be used. Costings for Urban LMDS: (the costing have been compared against HFR baseband >5 years out from today) • The OSSB showed up to be a lower cost solution then digital baseband due to lower site acquisition and rental costs Which is due to the greatly reduced size and complexity of the remote radio unit. Moreover it is assumed that the modest power supply requirements of the OSSB approach will make associated costs lower than for the Digital Baseband case. The Table 4 below shows again the results of the above economical discussions and may be compared with the Table 3 where ‘just’ technical aspects of HFR applications have been considered. page 18 (41) © 2000 EURESCOM Participants in Project P816-PF
  31. 31. Deliverable 3 Implementation Strategies Technology Application BB DFB OSSB PEAM CPEAM LPEAM Wireless LANs UMTS Microcell DCS 1800 Suburban LMDS Table 4 Recommended Application/Technology Combinations In a summary it can be said that cost savings are possible with a (non-baseband) HFR technology provided that: • Lower site acquisition and rental costs can be negotiated • Lower power supply costs can be obtained • The predicted maintenance cost reductions can be realised It should be said once more that the cost difference has little to do with any technological details – it’s dominated by the impact of the overall architecture. The decision of whether to use HFR technology (and the choice of which HFR technology to use) actually has very little to do with detailed technological issues. HFR technology (excluding digital baseband) can give cost reductions via the following mechanisms: • The simplification of the remote site can greatly reduce the maintenance costs for the system. • The simplification of the RAU can greatly reduce site acquisition and rental costs It is these two mechanisms that have resulted in the non-baseband HFR technologies doing so well in the costing studies. Indeed, they emerge as clear winners – a reassuring message as it implies that results are not sensitive to moderate changes in the input cost values, many of which are just estimates. A third mechanism has also had a significant impact on these studies – the costs of providing a power supply at the remote site. There are significant cost differences for the various technologies in this respect: • Passive EAMs (PEAMs) require no power supply at the remote site • Centrally Powered EAMs (CPEAMs) do not require a ‘mains’ supply at the remote site – instead, they rely on a low voltage feed from the central site • All other solutions require a mains supply to the remote site In this respect, therefore, PEAM technology emerges as clear winner. However, for the applications considered here, the cell size limitations imposed by the use of PEAMs more than outweighed the benefits of this, preventing it from costing in for any application. Centrally powered EAMs do cost in for the UMTS Microcell application, based on the reduced power supply cost. However, this cost saving is dependent on copper conductors being available. The three mechanisms mentioned above also very clearly explain why HFR technologies were shown to be unsuitable for wireless LAN applications: • Reduced Maintenance Costs: All equipment in the wireless LAN application is indoors and easy to get access to – centralisation will have comparatively little benefit • Site Costs: There are no site costs for wireless LANs © 2000 EURESCOM Participants in Project P816-PF page 19 (41)
  32. 32. Implementation Strategies Deliverable 3 • Power Supply: Power supplies will almost always exist in an office environment Thus, the wireless LAN application does not allow any of the key advantages of non- baseband HFR to be exploited. page 20 (41) © 2000 EURESCOM Participants in Project P816-PF
  33. 33. Deliverable 3 Implementation Strategies 4 Frequency survey and regulatory background The frequency and regulatory issues related to the wireless systems as discussed in the sections above are highlighted in this section. The main focus is on Europe, however there will be also a look on the US practice concerning LMDS. 4.1 Organisations responsible for frequency management in Europe The matter of global frequency management and international radio regulation belongs to the ITU (International Telecommunication Union). It recommends and co-ordinates allocations to assure equitable sharing of spectrum resources. The 186 member countries of the ITU decide on spectrum allocations for existing and planned radio communications systems at WRCs (World Radio Conference) organised at regular intervals of 2-3 years. As the demand for spectrum increasing with liberalisation, competition and technological innovation in the telecommunication sector, fair frequency allocation is not merely a technical task but an important issue of economic and political decisions. In Europe CEPT (European Conference of Postal and Telecommunications Administrations) is the regional regulatory telecommunications organisation, which comprises 43 European countries. Within CEPT the ERC (European Radiocommunications Committee) is responsible for all the radio communications issues, frequency co-ordination and radio regulation, and preparation of the European positions for the ITU radio conferences. As each ITU member country has one vote at the WRC, agreements harmonised at CEPT level create better bargaining position and voting power for Europe. The ERC has an expert body, the ERO (European Radiocommunications Office), which assists the ERC in the long term planning of the radio spectrum, liaises with national frequency management authorities and provides support in co-ordination of research studies and consultations. CEPT/ERC co-ordinates the work with ETSI in the frame of a MoU. Within ETSI, TC ERM (Technical Committee EMC and Radio Spectrum Matters) acts as an interface for CEPT on spectrum and regulatory issues concerning the emerging new technologies and inter-system characteristics. © 2000 EURESCOM Participants in Project P816-PF page 21 (41)
  34. 34. Implementation Strategies Deliverable 3 UN Europe EU Organisation ITU CEPT ETSI Responsible WRC ERC/ERO TC ERM Forum/Body Documents International European Table Regulation; Radio of Frequency Deceison; Regulation Allocations and Directive; Utilizations; Recommendation; - ECP; Resolution; - ERC Dec/Rec Communication National Regulatory Authorities Figure 15 Organisations dealing with spectrum management and utilisation 4.2 European frequency co-ordination Frequency assignment belongs to the responsibility of the national authorities, however it must be in conformity with the CEPT/ERC decisions and with the EC law in EU member states. 4.2.1 Long term planning: DSI Between 1993 and 1995 the ERO on behalf of CEPT/ERC prepared the European long-term strategic spectrum plan in the form of Detailed Spectrum Investigation studies in two phases: • DSI Phase I in 3400 MHz - 105GHz frequency bands, • DSI Phase II in 29,7MHz - 960MHz frequency bands. The third phase of DSI in the 862MHz - 3400MHz frequency bands is still in progress. The complete European frequency harmonisation – the development and adjustment of the European Table of Frequency Allocations and Utilisation according to the future needs - will be implemented by the year 2008. 4.2.2 Frequency survey As discussed in section 1 and 2 different optical feeder systems exist and may be used to transmit the different radio signals to a remote antenna place. However, as has been seen from section 3 not every HFR system may give an economical benefit compared to baseband transmission. Nevertheless, the frequency issues if transmitting radio signals are important, as for the majority of radio systems licensing is required. page 22 (41) © 2000 EURESCOM Participants in Project P816-PF
  35. 35. Deliverable 3 Implementation Strategies DECT: Directive 91/287/EEC designated co-ordinated frequency band of 1880-1900 MHz for the introduction of DECT into the Community from 1992. The Directive has been implemented by all Member States, though in some countries the band reserved for DECT is partly occupied by other systems (mainly military telecommunications networks, or digital fixed links). In most countries DECT is used as a terminal technology rather than as a service provided to third parties. Directive 96/2/EC claims that certain Member States were still preventing the use of these frequencies for public services by refusing to grant licences to companies which intend to start offering DECT services. According to Article 2 of Directive 96/2/EC allocation of licences for public access/Telepoint applications including systems based on DECT can not be refused. The lack of a clear European regulatory status of DECT- based wireless access systems resulted serious delays concerning the development of national DECT regulations, which restrained particularly the provision of public services. GSM900/1800: Council Directive 87/372/EEC designated co-ordinated frequency band in the 900MHz spectrum for the introduction of GSM into the Community from 1987. The Directive has been implemented by all Member States, though in some countries some parts of the 900MHz band is partly occupied by analogue cellular systems. Directive 96/2/EC prescribed for Member States to grant DCS1800 licences not later than January 1, 1998. UMTS: To facilitate the successful introduction of UMTS in Europe, UMTS receives political support at Community level. In this context both the Council and the relevant expert bodies take the necessary steps. Thus ERC intends to harmonise the use of the UMTS spectrum across the CEPT countries. The CEPT/ERC/DEC(97)07 decision requires that administrations make available at least 2 x 40 MHz within the UMTS terrestrial band by 2002. The latest draft CEPT/ERC/DEC(99)HH decision, which is under public consultation at the moment, forms a harmonised spectrum scheme for UMTS for FDD and TDD operations. Public UMTS operators will have separate bands, while private office systems will share UMTS band allocated to private operators and will operate in a self-coordinated manner. The question of additional bands for UMTS/IMT-2000 is under investigation for WRC’00. The European Parliament and the Council established a co-ordinated authorisation approach for the introduction of UMTS in the Community. According to Decision No 128/1999/EC Member States shall introduce UMTS services on their territory by 1 January 2002 at the latest, and establish an authorisation system for UMTS not later than 1 January 2000. Additional implementation period of 12 months is possible beyond the above dates. Some countries have already started the licensing procedure; e.g. in Finland 4 UMTS licences have been granted, in Sweden the process is going on. LMDS/MMDS/MVDS: International Radio Regulations do not apply the system abbreviations such as LMDS, MMDS, MVDS at all. For LMDS a brand new draft CEPT/ERC/DEC(99)AP Decision is under public consultation process for the 24.25GHz to 29.50GHz band. For MVDS the CEPT/ERC/DEC/(96)05 Decision allocated the 40.5 to 42.5GHz band in 1996. This Decision in under withdrawal now, it will be replaced by the Draft ERC/DEC(99)BB being under public consultation. The draft Decision assigns the frequency band of 40.5 to 43.5GHz for the of Multimedia Wireless Systems (MWS), including Multipoint Video Distribution introduction © 2000 EURESCOM Participants in Project P816-PF page 23 (41)
  36. 36. Implementation Strategies Deliverable 3 Systems (MVDS). In the 25th report of the ERC 17,3-17,7GHz is indicated as a possible band for MVDS. In the USA the first LMDS auctions had been kept in February 1998, after years of delay. While LMDS spectrum has been already auctioned and licences have been assigned in the US market for one year, operators are slow to invest in the infrastructure and start the roll-out of the network. The reason behind this is that LMDS can be still viewed as an immature technology and the market is waiting for future-proof, bi-directional, digital, multi-service systems. LMDS equipment - both infrastructure and customer premise equipment - are still expensive, so the costs to serve a customer are similar to that of a wireline provider. Cost advantage may come from the high scalability of LMDS technology, which allows start with minimum investment and follow up gradually as demands emerge. HIPERLANs: The CEPT/ERC/DEC(96)03 Decision designated the 5.15 - 5.25GHz band for HIPERLAN Type 1 in 1996. An additional 50MHz (5.25 - 5.30GHz) is already available on a national basis in some CEPT countries. CEPT T/R 22-06 recommends the 17.1 - 17.3GHz [4] band for HIPERLAN Type 4 on a non-protected and non-interference basis. MBS: For MBS the 40 and 60GHz bands are proposed. The 60GHz band (62-63 GHz for down-link and 65-66 GHz for up-link) is under consideration as well. Going to very high frequencies, ray-like propagation occurs, so there are no refraction, diffraction and reflection effects. It is suggested that the optimal frequency band for high density systems is the 59-66GHz band, where the atmospheric attenuation peaks at about 15dB/km and refraction and diffraction effects are minimal. Additional interference protection is provided by the inability to pass through obstacles, which are virtually transparent at lower frequencies. This is valid for the human body as well, so diversity transmission must be applied to solve this problem. Due to the short range this band is suitable primarily for the provision of local coverage. 4.3 Regulatory background The allocation of radio-frequencies for mobile and wireless services falls within the competence of the national telecommunications authorities. Frequency assignment is often dealt with in the framework of service licensing procedures. Licence fees should in general just recover the administrative costs, and should be published. In case of individual licences however it is allowed to impose charges which reflect the need to ensure the optimal use of these resources and thus auctions and administrative pricing are permitted. The number of licences generally should not be limited. However, this may be necessary in case of wireless services as the spectrum is rare, then transparency of the procedures must be ensured with suitable publicity. The method of the licensing process can be: • chosen by the authority: • first come first served, • comparative bidding, • auction, • drawing. Licensing conditions may not contain unjustified technical limitations, thus Member States should not prevent combination of licences and restrict the service provision page 24 (41) © 2000 EURESCOM Participants in Project P816-PF
  37. 37. Deliverable 3 Implementation Strategies based on different technologies making use of distinct frequencies, where multi- standard equipment is available. This point can be of interest to HFR implementation where multiple radio standards may be transmitted over the same fibre for economical reasons. Since spectrum is a scarce resource, allocation of frequency bands may be a source of income for the budget. Settling the frequency fees to be paid for the different bands is within the competence of the national authorities, there is no united European regulation in this respect. Fee structures differ from Administration to Administration. In some Member States (e.g. Finland) the frequency fee is just for covering the administration costs of frequency management. Some other countries determine the fee according to the utilisation of the band (e.g. using the band for fixed wireless access is less expensive than for mobile applications). There are examples for the creation of a price table based on the used frequency range, output power and the validity of the licence (local, regional, nation-wide). The measure of frequency fees has a strong effect on competitiveness. In the evaluation process of wireless against wireline technologies, frequency fees occur as regular costs to be paid monthly according to the number of base stations and radio channels in use in addition to the licence fee. The spectrum pricing method can adversely impact the competitiveness of a technology and the market. © 2000 EURESCOM Participants in Project P816-PF page 25 (41)

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