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Spectrum for Asset Tracking Mobile Data Networks using Spread Spectrum TechniquesA Consultative Document |
In the past few years a number of companies have developed systems which could provide asset tracking services utilising spread spectrum techniques. Proponents of these systems argue that the market for relatively low cost asset tracking services is potentially huge and is a niche market not being adequately served by the existing mobile data network operators.
The proposed asset tracking systems require an allocation of radio spectrum as, at present, no such allocation exists for this particular type of system. Consequently the development of these systems is currently constrained by the need to allocate radio spectrum. This consultation document explains the perceived market for asset tracking, reviews the spectrum issues associated with providing an allocation for these services, contains a number of proposals and seeks expressions of interest in providing asset tracking services in the UK. Annex A relates to work carried out by the RA on a typical candidate system.
The market for asset tracking services and the need to identify spectrum has also been recognised at the European level in a report produced by the European Radio-communications Office (ERO). The ERO Report (1) was published last year and reviewed all the known systems in operation or which were seeking radio spectrum.
The Radiocommunications Agency (RA) is supportive of the need to address this issue at the European level, as this has clear advantages in terms of providing a larger market for products. The economies of scale that a harmonised European market would offer is clearly the preferred way to develop new markets for radio based products but in this instance the RA is proposing that a UK allocation is appropriate given the likely difficulties in agreeing a harmonised allocation throughout Europe in view of the diversity of systems and technologies.
Notwithstanding any decision to seek a UK solution, the RA will continue to promote the adoption of an European allocation for asset tracking systems. It is possible that a similar allocation will be made in both cases and, if so, there may be scope to align the allocations in due course.
(1. ERO Report on Alarm Systems Tracing Lost or Stolen Items. Published 1998. Web site: http://www.ero.dk)
Asset tracking is an automatic tracking and messaging system designed to provide real-time asset tracking and two-way data services. As such, this niche market falls within the public mobile data services licence category which is described in paragraph 1.2.
As stated, the RA has received a number of proposals for the establishment of national networks for asset tracking services based on spread spectrum techniques. Whilst there are some differences between the systems, the common elements are as follows:-
The systems consist of four major elements:-
The second element of these networks could be implemented by either using existing pager networks or be integrated as an element of the asset tracking network. The preferred frequency for many of these proposed systems is around 900 MHz for the spread spectrum element, the 'paging' element would be, ideally, in close proximity to this allocation but could be anywhere from 100 - 1000 MHz.
1.2 Current Mobile Data Market
Mobile data networks provide two way transmissions of non-voice messages (data). The data is usually transmitted in "packet" form, meaning it is sent in short, high speed bursts rather than in real time. For example, if sending a text message, the text is typed into a terminal and stored until the user is ready to transmit. This approach makes these networks very spectrum efficient, since a message which might take many seconds to send by voice or typed in via a keyboard can be transmitted over the air as block data in a fraction of a second.
Mobile data services are currently provided in the UK by four licensed operators namely Cognito Ltd, Ram Mobile Data Ltd, Vodafone Value Added and Data Services Ltd, (formerly Paknet) and Securicor Datatrak Ltd who provide various data services and one licensee, Tracker Network (UK) Ltd, which provides an Automatic Vehicle Location (AVL) system. Cellular GSM/ TETRA and PAMR also provide data functionality in their service provision but, at present, data accounts for only a small percentage of the total traffic (voice + data) capacity. The four data networks cover approximately 90% of the UK, with approximately 200 base stations in each network. Since services were launched in 1993 the overall public mobile data market has grown to approximately 65,000 subscribers.
1.3 The estimated cost of the service provided by networks using spread spectrum techniques is anticipated to be lower than current prevailing rates and should, therefore, expand the overall market for these services significantly. Spread spectrum systems also provide frequency sharing possibilities between an asset tracking network and an existing incumbent service. These options are further explored in paragraph 3.
1.4 Such systems, as well as providing an efficient, low cost solution for both private vehicle and fleet operations, also lend themselves to such applications as home security, telemetry/telecommand, industrial plant and equipment.
The Department is keen to receive the views of all interested parties on the future of mobile data communications in the UK and the underlying assumptions on which they are based. Comments should be sent to :-
Brian Last
Radiocommunications Agency
Wyndham House
189 Marsh Wall
London
E1 9SX
Nick Williams
CII Division
Department of Trade and Industry
2.56 Grey
151 Buckingham Palace Road
London
SW1W 9SS
Please note the closing date for comments is 24th June 1999
2.1 Written comments will be made publicly available except where respondents indicate that their response or parts of it are confidential. Respondents are requested to separate any confidential material into a clearly marked confidential annex. Unconditional permission will be assumed unless the author expressly states otherwise. Any copyright attached to responses will be assumed to have been relinquished unless it is expressly reserved.
2.2 It would be helpful if five copies of all comments could be sent to each address. An electronic version of your comments either on disk or E-mail would be appreciated. Additional copies of this document can be obtained by contacting 020 7211 0211.
3.1 The RA has examined options and, at present, four possible allocations are under consideration. Only one of these options will be chosen for asset tracking applications. These options are;
863 - 865 MHz
This band is designated within CEPT Recommendation 70-03 for use by Wireless Audio applications and consumer radio microphones. The upper part of this band (864-865 MHz) is currently used by CT2 cordless telephony products.
The RA has conducted sharing compatibility studies between spread spectrum CDMA systems and Wireless Audio devices (an overview of this work is contained in Annex A of this consultation document). The spread spectrum characteristics of a representative asset tracking network were used in these studies and the report concludes that sharing is acceptable, based on certain operational constraints and a defined user density per unit area.
865 - 867 MHz
This band is currently used by Cordless Telephony CT2. The future of CT2 is under review and may be subject to a further consultation later this year. Evidence suggests that the CT2 band is lightly used and is in decline. The ability of CT2 to dynamically assign channels to avoid interference may facilitate sharing with another user.
867 - 869 MHz
This band is currently split between CT2 devices (867 - 868MHz) and Short Range Devices as defined in CEPT Recommen-dation 70 -03. This CEPT Recommendation permits spread spectrum devices, however there is interest in providing an allocation for a low power paging return path which would not be a good candidate for sharing with spread spectrum asset tracking systems. The CEPT group responsible for this work will present its findings in May after which a clearer picture will emerge.
868 - 870 MHz
This band has been harmonised within CEPT band for Short Range Devices and forms part of Recommendation 70-03. It is referred to in part in option (c) above. The RA is currently conducting studies to determine the suitably of sharing between asset tracking systems and other forms of Short Range Device.
Paging channels
A small number of paging channels are required by these systems unless the tracking network utilises existing paging networks. It has not been possible to identify any spectrum around 900MHz. Channels are available for this application around 200 MHz. The radiated power for these stations should be assumed to be limited to 25 watts, ERP.
3.2 In considering such factors as propagation characteristics, reuse and ease of implementation, the Agency has considered various candidate bands below 1 GHz. Recent sharing studies carried out within the Agency indicated that Cordless Audio Devices could successfully share the spectrum with Cordless Telephony CT2 equipment operating between 864.1 and 868.1 MHz with a small loss of operational channels. In considering the further sharing with a spread spectrum asset tracking system it is envisaged (paragraph 1.2 refers) that such systems could be accommodated within a bandwidth of 2 MHz within the 863-868 MHz without undue loss of performance from either the Cordless Audio Devices or the Cordless Telephony CT2 systems.
Asset tracking public mobile data networks will require licences under both the Telecommunications Act and Wireless Telegraphy Act. It has been decided that these licences will be awarded through a competitive process and not through an auction. It is envisaged that the prevailing administrative spectrum charge will be applied, i.e. £1,584,000 for the spread spectrum allocation and £9,900 for each paging channel. These charges are payable on an annual basis and may be discounted in the start-up years to reflect roll-out practicalities and the current transitional arrangements (2).
(2 Spectrum Pricing: Implementing the Second Stage. Published 1998.)
Spectrum Issues:
1) That a single allocation be made for a spread spectrum asset tracking system in one of the identified bands discussed in paragraph 4 together with the associated paging channel
Compatibility Issues:
2) That, at present, the focus is on allocating the 863 - 865 MHz for the spread spectrum element of the asset tracking system. The tests conducted at the RA compatibility facility indicate that sharing with Wireless Audio Devices is feasible assuming one operational system. Comments are invited on the work undertaken and the conclusions reached.
3) Applicants should make clear whether their proposed system falls within the generic technical parameters used in the sharing studies (paragraph 1.1 refers) and, if not, further analysis may be required to determine if sharing is feasible.
Licensing Issues:
4) Applicants wishing to operate a nationally based asset tracking network are invited to submit an outline business case which would need to demonstrate that the applicant had the necessary technical, financial and legal com-petencies to implement a national network in a timely manner, e.g. within five years of an award of a licence, preferably within three years.
5) What, if any, roll-out obligations are needed? Is the proposed spectrum charge sufficient to dissuade speculative bids?
Spectrum suitable for a typical CDMA spread-spectrum asset tracking system is being sought in the UK.
A recent investigation was conducted to assess whether this type of system could operate satisfactorily within spectrum located in the 863-870 MHz band without causing unacceptable interference to the existing services. It is envisaged that a single national system can be accommodated within this spectrum without causing undue interference to other adjacent services.
The services considered were;
The sensitivity and protection requirements of typical equipment used by the two existing services were determined from measurements and specifications. Wanted field strengths were calculated using an indoor propagation model, and interfering field strengths (for various percentages of the time) were predicted using an extended Hata propagation model and Monte Carlo analysis. The magnitude of the interference that should be anticipated was assessed for specific scenarios. In addition, a variety of subjective listening tests were also conducted to determine the subjective effect of interference under normal operating conditions.
A variety of subjective listening tests were also conducted to determine the subjective effect of 'real' interference under 'real' operating conditions i.e. under conditions where the occurrence and level of the interference is random, and the wanted signal is also suffering other impairments due to fading etc. It was confirmed that the subjective magnitude of the interference present at the lower wanted field strengths was being reduced (masked) by the presence of other impairments such as noise and fading.
The findings were analysed and the following conclusions drawn;
The example CDMA system used in the study was an automatic tracking and messaging system designed to provide real-time asset tracking and two-way data services.
The system consists of four major elements:
Summary of Responses
(February 2000)
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