Implementing geolocation

Summary

Executive summary

The roles of different types of spectrum

1.1 Spectrum is typically managed in one of two ways. Most spectrum is licensed to a particular user, such as a mobile network operator, who has exclusive rights to make use of the spectrum. The remainder, around 6% or so, is exempted from licensing. Unlicensed spectrum is used by a wide range of devices, most notably devices based on the WiFi and BlueTooth standards. .

1.2 In our Spectrum Framework Review of 2004 we noted that both types of spectrum were important. Licensed spectrum enables the deployment of large national infrastructures whereas unlicensed spectrum enables innovative new devices and applications. Since then, there has been dramatic growth in the use of WiFi and Bluetooth, and many new applications for short-range wireless connections.

1.3 Of course, not all innovative ideas are successful and alongside WiFi and BlueTooth sit some initiatives that have yet to gain any traction, such as ultra-wideband (UWB). Our role however is to enable as many new ideas to be tried as possible so that the market and consumers can determine which should succeed, without trying to pre-judge which will be the most successful.

More unlicensed spectrum is needed

1.4 With the success of WiFi has come increased congestion in the frequency band around 2.4GHz where it is commonly deployed. With many ideas for new applications that might be deployed in unlicensed spectrum there is global interest in finding new frequency bands.

1.5 Around the world interest has settled on frequencies in the UHF band (between around 500MHz and 800MHz) used for broadcast TV. These frequencies have two key advantages - there is a relatively large amount of spectrum and signals travel much further than in the bands used for WiFi. However, this spectrum is already used for TV broadcasting.

1.6 It has been known for some time that TV transmissions do not take up all of the spectrum with some gaps being needed to avoid interference. These gaps, or "white spaces", cannot be used for additional high power TV transmissions. However, lower power unlicensed devices could operate in these white spaces, as long as they can accurately identify where they are.

1.7 Studies as to how the white spaces can be identified and used without causing interference have been taking place for a number of years. There is consensus that the optimum approach is likely to be based on a central database, which would provide information to low-power devices as to whether it is safe for them to transmit, taking into account the location of each device. Trials of a number of new applications using this geo-location database approach are now taking place, particularly in the US and the UK and appear promising.

We have been at the forefront of promoting white space usage

1.8 We believe that enabling new applications in white spaces fits well with our duties to maximise the value of the use of spectrum for citizens and consumers, ensure efficient use is made of it and encourage innovation. Hence, we have led the way with many important studies, measurements and modelling activities backed up with consultation around principles and approaches. As a result of these, we are now proposing a framework whereby interested parties can provide white space databases including exempting white space devices from the need for licensing.

1.9 In enabling white space access we hope that a range of valuable new applications will emerge but as with any innovative new technology we cannot predict what will actually happen. Hence, our approach is to allow as much flexibility as possible for the market to try a range of applications. Equally, we are ensuring that if white space access does not prove successful then the licensed use of this spectrum will not be impacted nor will significant regulatory investment be wasted. We do not expect to see large scale commercial activity before around 2014 and would expect penetration of devices to take some years to build after this. We do not expect white space devices (WSDs) to displace broadband communications via cellular or WiFi but to provide an additional mechanism for communications most of which will be short-range such as enhanced home wireless routers, rural broadband access, data networks in applications such as hospitals and urban wireless data networks.

1.10 In previous documents we have explored the use of unlicensed spectrum, different approaches to white space access and the general principles behind the use of a "geolocation database" to inform devices as to which white spaces are available. We expect this to be our final consultation on this topic focussing in detail on the specific technical and legal instruments needed.

How geolocation will work

1.11 The diagram below provides an overview of how we propose access to the white spaces based on geolocation will work in practice. Broadly, a "master" WSD will first consult a list of databases provided on a website hosted by Ofcom (1 and 2). It will then select its preferred database from this list and send to it parameters describing its location and device attributes (3). The database will then return details of the frequencies and power levels it is allowed to use (4).

1.12 A master device may also signal to a "slave" device (a device that does not need to contact the database) as to the frequencies and power levels it may use when communicating with the master device (5).

1.13 The database would be dependent on access to information about licensed usage in the band provided for digital terrestrial television (DTT) and programme making and special equipment (PMSE - mostly wireless microphones in this band), and algorithms specified by Ofcom to derive the frequencies and channels that devices may use. This should ensure that WSDs do not cause harmful interference to licensed users.

Necessary regulatory instruments

1.14 In order to implement the proposed geolocation process, Ofcom will need to publish a Statutory Instrument (SI) exempting appropriate devices from the need for a licence. In essence, master and slave devices that consult a database listed on the Ofcom website and then only transmit in accordance with the information received would be exempt from licensing.

Obtaining a database listing

1.15 We consider that the database(s) may be more efficiently run by commercial entities as they are likely to have the necessary IT resources. Those interested in running a database would approach Ofcom in order to apply for a listing on a website hosted by Ofcom (or a trusted party) from which WSDs can then select their preferred database. We would need to consider applications against certain minimum requirements and may require entry into a contract and payment for the listing of the database.

Next steps

1.16 This consultation invites responses on the approaches proposed by 7 December 2010.

1.17 During this period and afterwards as appropriate we will work with European bodies such as the Electronic Communications Committee (ECC) within the Central European Post and Telecommunications (CEPT) organisation and the European Commission (EC) to seek a harmonised European solution for the implementation of WSDs. We will also liaise internationally with other bodies such as the Federal Communications Commission (FCC) and other worldwide standards bodies to seek global interoperability for devices as far as possible on a global basis. This may lead us to adopt alternative approaches to the proposed geolocation process.

1.18 At this stage we are uncertain about the balance of costs and benefits associated with these proposals. Until we move ahead further in this process these will not become clear. It may be that this balance is such that we choose not to proceed or we seek alternative approaches. Hence, we are unable to make any commitments that we will pursue the proposals set out here.