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Appendix A |
Broadband Fixed Wireless Access
The concept of BFWA can be said to have developed from the convergence of fixed and broadcasting radio services resulting from the increasing need for delivery of broadband digital services to individuals, households and businesses of all sizes. A BFWA access network essentially provides the connection between core network services and the customer. The core network services could typically consist of a combination of the Public Switched Telephone Network (PSTN), Public Switched Data Network (PSDN) or CAble TeleVision (CATV) or other such networks. The general system architecture of the BFWA access network concept is shown in Figure A1.1.
Figure A1.1 - BFWA general system architecture
A1.2 Projected BFWA Services
Broadcasting services have been, in the main, unidirectional to the end user with mostly broadcasting content, whereas telecommunication services to end users have been limited in capacity and speed.
Projects and systems being developed from both the broadcasting and telecommunication sides are intended to provide a large variety of services to end users far beyond the scope of the more traditional services. Broadband (multimedia) services are likely to include the following envisaged applications:
A1.3 Data rates
BFWA services are identified by the maximum bandwidth or bit-rate available to the customer or end user requiring the service. Increasing digitisation of services and the associated improvement in radio spectrum usage along with an increasing customer awareness of the potential of information services has led to a demand for these broadband services capable of providing greater customer choice and freedom along with high speed delivery. In the light of current generally available services operating at data rates around 144kbits/sec, broadband services are usually considered to be those offering data rates in excess of 2 Mbit/sec. However, this is very much a minimum figure and it is expected BFWA systems should provide for data rates of around 2 to 5Mbits/sec to the end user in order to compete with, or complement, other delivery technologies.
However, it should be recognised that the data rates ultimately offered to BFWA customers will depend on the operators' spectrum allocations, their network deployment strategies and radio planning.
A1.4 Network architectures
The geography of the service area, customer density, services offered and the available technology are the key parameters that will enable operators to chose to deploy technologies and network architectures to serve the potential users. A BFWA network could be configured using point to point (P-P), point to multi-point (P-MP) or mesh architectures. P-P networks use a dedicated link between the Access Point Transceiver (APT) and the Customer Premises Equipment (CPE). P-MP networks use a cellular deployment of APTs serving CPEs within the coverage area of the APT. Mesh networks do not have APTs, but alternatively have each CPE acting as a repeater to one or more other CPEs to form an interconnected mesh.
Fixed Wireless Access (FWA) is considered as an application within the Fixed Service for the purposes of Radio Regulation by the ITU. There are a number of Fixed Service frequency bands between 2GHz and 40GHz but only some of these have been identified for use by FWA. Within Europe ERC/CEPT Recommendation T/R 13-04E1 identifies a number of Fixed Service frequency bands preferred for FWA between 2GHz and 30GHz. Some UK specific operation exists in frequency bands other than those covered by Recommendation T/R 13-04E.
1 ERC Recommendation T/R 13-04E - Preferred frequency bands for Fixed Wireless Access in the frequency range between 3 and 29.5GHz - available from http://www.ero.dk
In the UK there are a number of licensed FWA systems in spectrum between 2GHz and 30GHz. Although FWA has been available in the UK since 1997, the extent of roll-out of services has been slow and in some cases, services have either ceased or not proceeded and some spectrum allocations may therefore become available for reassignment shortly. These systems have been or continue to be capable of providing FWA services of varying capacity, ranging from simple telephony to broadband applications.
A2.1 Frequency bands for BFWA type applications
Two frequency bands have been identified for BFWA in the UK. These are parts of the 28GHz band, the subject of this Memorandum, and the 40.5-43.5GHz band.
28GHz
Use of parts of this band (27.5-29.5GHz) is consistent with the Recommendation T/R 13-04E (mentioned above) being one of the bands identified as "preferred" for FWA. However, the frequency band is shared with other users, principally in the Fixed Satellite Service, who may need to share its use. Work carried out within the European regulatory bodies has shown that it may be difficult for FWA to share the band with certain types of Fixed Satellite Service, where both services entail a high density uncoordinated deployment of terminal stations.
To overcome this difficulty ERC Decision ERC/DEC/(00)092 has been published which identifies specific parts of the frequency band to be used for either application. This would be for either the Fixed Service or the Fixed Satellite Service. There is also identified a so-called "conditional" part of the band which Administrations are free to allocate to either the Fixed Service or the Fixed Satellite Service, on a geographical basis. The Fixed Satellite Service type of operation anticipated in the exclusive and possibly conditional part of the band, is associated with the future deployment of interactive satellite systems known as SITs (Satellite Interactive Terminal) and SUT's (Satellite User Terminal). It must be noted that the Decision relates only to uncoordinated Fixed Satellite Service stations and will be reviewed two years from its adoption date.
2 ERC/DEC/(00)/09 "ERC Decision of 19 October 2000 on the use of the band 27.5 - 29.5GHz by the fixed service and uncoordinated Earth stations of the fixed-satellite service (Earth-to-space)" - available from http://www.ero.dk
The
spectrum on offer in this 28GHz licensing process is drawn from the part of
the band identified where the use and deployment of uncoordinated Fixed Satellite
Earth stations, is not permitted. Further use of the remainder of the 28GHz
band by either the Fixed Service or the Fixed Satellite Service is under consideration
in the UK. Further use by either service will depend on many issues relating
to the demand for these services and will be addressed through the RA/Industry
Fixed Link Consultative Committee and the Satellite Consultative Committee in
due course.
40GHz
Use of this band in the UK was identified along with the 28GHz band in the original BFWA Agency consultation document3. Within Europe the band has been harmonised by an ERC Decision ERC/DEC/(99)15 for use by so-called MWS (Multimedia Wireless Systems) which are a form of BFWA evolving towards a convergence between fixed telecommunication services and broadcast distribution services.
3 "Wireless in the Information Age; delivering interactive multimedia to workplace and home" - published in July 1999
Being a new application in the band, there has been much discussion on the frequency management and spectrum engineering issues related to its use within the regulatory and standardisation bodies within Europe. At this time, it is difficult to be absolutely certain about the services that may find application in the band and the spectrum packages that will consequently be on offer in the UK licensing process.
However, it is anticipated that 40GHz services may address residential markets as well as business markets. Within the industry some operators view the need to supply "entertainment services" as a key driver which may lead to a requirement for large, asymmetric frequency assignments. Assignments are likely to be several hundred megahertz.
Developments on these issues have been tackled by groups within both CEPT and ETSI as well as further afield. CEPT are expected to agree recommended guidelines for the accommodation and assignment of MWS systems in the 40GHz band in October 2001. In addition, ETSI will soon begin the approval process for their MWS equipment standard.
A European Decision is also currently being developed concerning the use of the FS and the uncoordinated FSS/BSS (Broadcasting Satellite Service) earth stations within the band 40.5-42.5GHz.
Patricia Hewitt, the then Minister for Small Business and E-commerce, announced on 14 January 2000 that the Government planned to make radio spectrum licences available for BFWA at 40GHz in autumn 2000. However, following studies of the potential market and state of development for 40GHz technology, the Government decided to put back the timing of the award. It intends to hold discussions with industry during autumn 2001 on the options for awarding licences.
A2.2 Frequency bands for FWA type applications
2GHz (2025-2110MHz paired with 2200-2290MHz)
Following a competition in 1996, licences were offered to two companies, Zipcom (formerly Radiotel) and BT. The use of frequencies is geographically limited with the intention of providing remote areas of the UK with FWA services. BT have since decided not to deploy services and it is possible that some or all of that spectrum may be offered for re-allocation in the future.
3.4GHz (3425-3442MHz paired with 3476-3493MHz nominally)
A paired allocation of 2x17MHz from this "preferred" band as identified by Recommendation T/R 14-03E Annex A is available for re-assignment for FWA activity. Following a consultation at the end of 1999 and development work since then to optimise the opportunity, it is expected that licences will be re-assigned around the end of 2001. Following discussions with interested parties, the Agency has commissioned studies into the possibility of having a more uniform approach to frequency allocations. This would then allow for 2x20MHz with 100MHz duplex arrangement, to be accommodated. This approach would need to have due regard to existing services in that band. Due to bandwidth availability issues, data rates for FWA systems are likely to be lower than those offered by BFWA systems. Further information is available from the FWA section of the Agency web site.
3.6 - 4.2GHz (3605-3689 MHz paired with 3925-4009MHz)
A core allocation of 2x36MHz is licensed to the company Tele2 UK for providing FWA services. There is also provision to use an extension on a non-protected basis or, subject to agreement for individual cases on a co-primary basis, to facilitate co-ordination with other radio use in the band. Services are planned to continue rolling out widely in England, Scotland and Wales in the near future. Services provided range from telephony to fast data connections typically at rates of 384kbit/s but higher speeds may be possible. No further FWA licences are expected to be available in this band.
10GHz (10.125-10.225GHz paired with 10.475-10.575GHz)
Three paired assignments of 2x30MHz from this "preferred" band, identified by Recommendation T/R 12-05E Annex A but offset by 25MHz below the recommendation, were awarded in 1997 for providing FWA services. Two of the national licences, held by NTL and Cable & Wireless, remain in force. The third pairing is now subject to review as to its suitability for re-allocation.
A2.2.1 Licence exempt bands
2.4GHz (2400-2483.5MHz)
In the frequency allocation tables this spectrum is allocated to ISM (Industrial, Scientific and Medical) services and is available also for use by licence exempt4 services in the UK. Following successful trials and licensing on a restricted basis in Scotland by an operator, Atlantic Telecom, using low power spread spectrum technology, licences were offered throughout the rest of the UK for FWA services employing this technology. Atlantic Telecom was successful in obtaining licences for six regions and another operator was offered a licence for one region, subject to demonstrating the compatibility of equipment to be used. FWA service provision includes telephony and Internet connectivity at data rates up to 2Mbit/s.
4 Licence exempt means that only eligible devices may be used without a WT Act licence on a non-protected basis, but the terms of Exemption Regulations generally exclude any use for commercial (public third party) business purposes.
5GHz Band
In addition to the licensed Fixed Service bands used for FWA there is interest in a number of frequency ranges between 5150MHz and 5875MHz identified for licence exempt applications. Technology identified for use in these bands could to some degree provide broadband FWA although there are regulatory constraints and a number of issues related to the provision of public and private networks in licence exempt spectrum.
A consultation held last year considered the use of the bands between 5150MHz and 5875MHz. Differing parts of this frequency range are currently assigned to radio LAN devices and ISM users and several responses suggested that the spectrum could also support a number of applications including in-home distribution systems, short range nomadic public/private access systems which could include FWA services. A consultation document concerning public use of licence exempt spectrum, including 5GHz, is due to be published by the Agency around the time of publication of this Information Memorandum. This document will be available on the Agency's website and from the Agency's Library (Tel: +44 020 7211 0505/0502).
A2.2.2 Other Frequency Bands
12GHz
As a result of decisions made at the World Radio Conference (WRC) 2000, the Agency is considering the licensing of Broadcasting Satellite Service frequencies. It is possible that licences may be used in the future for up to 40 transponder frequency downlinks in a UK or European footprint, which may be used to deliver broadband and/or broadcast services.
26GHz (24.5-26.5GHz)
Parts of this band are identified as "preferred" by Recommendation T/R 13-04E. However, following RA/Industry consultation, the band has been designated for use in the UK by high capacity point-to-point services following a review of the fixed link spectrum and likely congestion in years to come. This band will not therefore be available for BFWA in the UK.
32GHz Band
Decisions at WRC 2000 now facilitate the use of the band 31.8-33.4GHz for the Fixed Service. This band is also identified as a band available for high density applications operating within the Fixed Service. Within CEPT a channel arrangement has been developed and agreed, ERC Recommendation (01)02. Work is also on-going within ETSI on P-P and MP equipment standards indicating a level of interest in the use of this band for FWA. However, within the UK the use of this band has not been identified for FWA and will therefore not be available for such use. Instead discussions are underway within the UK Fixed Link Consultative Committee regarding other Fixed Service applications i.e. backhaul. Within Europe, proposals have also been made to use the 32GHz band with the 31-31.3GHz band to cater for services that may require asymmetric assignments. Again this band has already been committed to other Fixed Service applications within the UK and therefore will not be available for FWA use.
47 GHz Band
Decisions at WRC 97 (Resolution 122) designated the bands 47.2-47.5GHz and 47.9-48.2GHz, for use by High Altitude Platform stations or HAPS (please refer to ITU footnote S5.552A). HAPS offer a service similar to satellite networks where a transmitting platform is positioned over the area to be served. These platforms would be in the stratosphere at a height of approximately 20-25km and are likely to take the form of balloons, airships or small aircraft. They would therefore be much closer to earth than current geo-stationary satellite systems. Much interest has been shown in this new delivery method for broadband services. However, there are many issues to resolve within ITU and CEPT regarding spectrum sharing aspects. At present, the Agency is not aware of any such commissioned services. Resolution 122 was modified at WRC 2000 to include extra frequency bands, but this only applied to countries within Region 3 (Asia and Australasia), the UK is in Region 1.
Figure A3.1 - 27.5GHz to 29.5GHz frequency band
The 27.5GHz to 29.5GHz band is shared on a co-primary basis between the Fixed Service (FS), the Fixed Satellite Service (FSS) [Earth to space] and the Mobile Service (MS). The FS allocation provides spectrum for BFWA as well as other fixed services such as traditional point to point fixed links. The BFWA spectrum has been planned in accordance with the CEPT Recommendation T/R 13-025 recommended channel plan. Paired frequency blocks of 392MHz are available and are given by 28.0525GHz to 28.4445GHz paired with 29.0605GHz to 29.4525GHz. The layout of the frequency band, showing the BFWA spectrum, is given in Figure A3.1.
5 ERC Recommendation T/R 13-02E - Preferred channel arrangements for Fixed Services in the range 22.0 - 29.5GHz - available from http://www.ero.dk
A3.1 BFWA Spectrum Packaging
BFWA licensing will be on a regional basis and the Agency believes there needs to be a minimum of three licences in a region to ensure competition between BFWA operators and other technologies. Any more than three licences in an area is unlikely to be commercially viable for the BFWA operators. The Agency position is that BFWA assignments of 2x112MHz provide sufficient capacity for full deployment of broadband services and the flexibility to work around and minimise inter-operator co-ordination difficulties.
Figure A3.2 - BFWA Spectrum Packages
Package 1 28.0525 - 28.1645GHz (BFWA 1) paired with 29.0605 - 29.1725GHz (BFWA 1')
Package 2 28.1925 - 28.3045GHz (BFWA 2) paired with 29.2005 - 29.3125GHz (BFWA 2')
Package 3 28.3325 - 28.4445GHz (BFWA 3) paired with 29.3405 - 29.4525GHz (BFWA 3')
A3.2 Inter-Operator Guard Bands
The Agency has applied 28MHz guard bands between the three licences in order to help strike a balance between maximising usable spectrum with a minimum of deployment constraints against the need to ensure equitable co-existence between competing operators. These guard bands have been developed taking due account of ERC Recommendation ERC/REC/(01)036 and associated ERC Report 997. The resulting three spectrum packages, which are consistent with the CEPT T/R 13-02 28MHz channel raster, are detailed opposite and shown in Figure A3.2
6 6 ERC Recommendation
ERC/REC/(01)03 - "Use of parts of the band 27.5-29.5GHz for Fixed Wireless
Access (FWA)" - available from http://www.ero.dk
7 ERC Report 99 - "The analysis of the coexistence of two
FWA cells in the 24.5 - 26.5GHz and 27.5 - 29.5GHz bands" - available
from http://www.ero.dk
A3.3 Placement of Channel Centre Frequencies within BFWA Assignments
The 28GHz UK Multipoint and Point to Point Radio Interface Requirement documents state that the channel plan is in accordance with CEPT Recommendation T/R 13-02 Annex C and lists recognised channel bandwidths from that plan that are specifically identified within the relevant ETSI standards. Additionally, ERC Recommendation ERC/REC/(01)03 considers "that operators may advantageously deploy equipment with a variety of central frequencies and bandwidths within their block 28MHz assignment to meet their operational needs" (a consideration supported by the Agency). It should be borne in mind that the restriction on the channel bandwidth (and specifically the maximum) is to ensure that the inter-operator co-existence measures are effective. Therefore, there is flexibility to employ any channel bandwidth up to 28MHz so long as the first channel at each end of the two by 112MHz blocks assigned to the operator are placed no closer to the block edge than the T/R 13-02 Annex C channel raster allows. In addition, the equipment will need to comply with the appropriate spectrum mask and spurious emissions requirements set out in EN 301 753.
A3.4 Inter-operator Co-ordination Guidelines
The Agency is not anticipating playing a major role in the co-ordination process. However, to facilitate the minimum of difficulties, the Agency has produced some guidelines to provide a basis for co-ordination between operators which are set out in Information Sheet RA390 which is available from the Agency website and Library.
A4 Sharing between BFWA and the Fixed Satellite Service
A4.1 Uncoordinated FSS Earth Stations
As can be seen from Figures A3.1 and A3.2 the 392MHz paired BFWA frequency blocks are coincident with the uppermost fourteen 28MHz channels in each sub-band of the CEPT T/R 13-02 channel plan. Referring to ERC Decision ERC/DEC/(00)09 it can be seen that both the 112MHz centre gap and the 47.5MHz guard band adjacent to the upper bound of the BFWA frequency blocks are allocated on an exclusive basis to uncoordinated FSS earth stations within Europe. It can also be seen that the spectrum adjacent to the lower bound of the BFWA blocks is identified as conditional for either FS or uncoordinated FSS earth station use. Decides 10 of ERC Decision ERC/DEC/(00)09 requires "that uncoordinated FSS earth stations shall not have their occupied band edges closer than 10MHz from the edges of the [BFWA] bands".
A4.2 Co-ordinated FSS Earth Stations
The frequency allocation tables, contained within the Radio Regulations, show that the 28GHz band (27.5-29.5GHz) is allocated to the Fixed Service (FS), Fixed Satellite Service (FSS) and the Mobile Service. Within the UK there are no current plans to allow mobile use of the 28GHz band. However, co-ordination may be required with the FSS, in the form of earth stations addressing both geo-stationary and non geo-stationary satellites. To date in the UK there has not been any applications for co-ordinated satellite earth stations, operating in the 28GHz band, and a moratorium is currently in force for the application and deployment of fixed satellite earth stations in the bands 28.000 to 28.500GHz and 29.000 to 29.500GHz. This position will be reviewed at the end of the auction process (estimated to be end of September 2002). Also use of other parts of the 28GHz band, not assigned to BFWA services, are for the use of uncoordinated satellite earth stations. These terminals are generally referred to as SITs and SUTs (Satellite Interactive Terminals, Satellite User Terminals) and their use and deployment are subject to an ERC decision, ERC/DEC/(00)09. There may be occasions where countries that wish to commission an earth station in their territory will inform the UK in accordance with the procedures contained within the Radio Regulations, Appendix S7. This will oblige the UK to consider the proposed earth station, whilst taking account of BFWA assignments, with a view to agreeing to co-ordinate the earth station.
A5.1 ETSI Standards
Standards for BFWA equipment and antennas operating within the 28GHz band have been developed within ETSI.
ETSI Working Group TM4 (WG-TM4) is tasked with producing coexistence standards. WG-TM4 has produced P-MP equipment standards covering the frequency range 24.25GHz to 29.50GHz for FDMA, TDMA (including multi-carrier) and DS-CDMA operation and a P-P equipment standard covering the frequency range 24.50GHz to 29.50GHz. They have also produced antenna standards for P-P and P-MP systems covering the frequency ranges 3GHz to 60 GHz and 26GHz to 30GHz respectively.
ETSI Project Broadband Radio Access Networks (EP BRAN) is concentrating on producing interoperability standards detailing the air interface to be used. Part of their work is looking at producing standards for a BFWA system known as HIPERACCESS (HIgh PERformance ACCESS). HIPERACCESS systems are expected to be applicable over the frequency range 3GHz to 60GHz, although the work is currently focused on the 32GHz and 40GHz bands.
A5.1.1 ETSI WG-TM4 Standards
The following list provides the title of the current published harmonised standards:
The following list provides the title of the current published equipment standards:
The following list provides the title of the current draft and final draft equipment standards that are currently going through the approval process and are soon to be published:
The following provides a list of the work items and status of equipment standards being developed:
The following list provides the title of the current published antenna standards:
The following list provides the title of the current published final draft antenna standards that are currently going through the approval process and are soon to be published:
The following provides the work item and status of a point to point antenna standard being developed:
A5.1.2 EP BRAN HIPERACCESS Standards
EP BRAN has published a technical report on HIPERACCESS requirements and architectures the title of which is:
EP BRAN has current work items to develop a technical report on the HIPERACCESS system overview and technical standards for the physical (PHY) layer and data link control (DLC) aspects of the system. The following list provides their respective titles and status:
A5.2 Standards in other fora
The ITU has developed standards for BFWA services. The IEEE 802.16 group is developing standards for BFWA in the range 10GHz to 60GHz. The ITU has produced standards in the form of recommendations in both the radiocommunication and telecommunication sectors:
A5.3 UK Radio Interface Requirements
The Radio Equipment and Telecommunications Terminal Equipment (R&TTE) Directive 1999/5/EC was implemented in the UK on 8 April 2000 by SI 2000/730. Amongst other things, the Directive replaced the previous national type approval regimes in place throughout the various Member States of the European Union (EU). The Directive introduced a harmonised set of "essential requirements" and conformity assessment procedures governing the placing on the market of equipment within its scope.
Article 4.1 of the Directive requires Member States to notify the European Commission of the interfaces they have regulated - this provides for a high level description of how the spectrum should be used. In the UK these notified interface regulations are in the form of documents called "UK Radio Interface Requirements".
The following lists the UK Radio Interface Requirements that are relevant to BFWA and are available from the Agency website and Library:
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