Peer-Reviewed Conference Paper

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1 - University of Canberra Research Publication Collection Faculty of Business, Government & Law Peer-Reviewed Conference Paper Citation: Freyens B.P., & Loney M. (2011). Digital Switchover and Regulatory Design for Competing White Space Usage Rights, Proceedings of IEEE DySPAN Conference, Aachen, 3-6 May 2011, doi: /DYSPAN Find this item in the UC Research Repository: Copyright: 2011 IEEE. Personal use of this material is permitted. Permission must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Version: This is the authors peer reviewed version of a work that was accepted for presentation at the 2011 IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN 2011) and has been published at Changes resulting from the publishing process may not be reflected in this document. University of Canberra, ACT 2601 Australia, Switchboard The University of Canberra is located on Ngunnawal Country. CRICOS number: University of Canberra / University of Canberra College #00212K.

2 Digital Switchover and Regulatory Design for Competing White Space Usage Rights B. P. Freyens, M. Loney University of Canberra ACT 2601 Canberra, AUSTRALIA Australian Communications and Media Authority PO Box 78, Belconnen ACT 2616 Canberra, AUSTRALIA PUBLISHED AS: FREYENS B.P., & LONEY M. (2011). DIGITAL SWITCHOVER AND REGULATORY DESIGN FOR COMPETING WHITE SPACE USAGE RIGHTS, PROCEEDINGS OF IEEE DYSPAN CONFERENCE, AACHEN, 3-6 MAY 2011 (IEEE XPLORE, Abstract 1 - There has been sustained regulatory support for the development and use of white space devices on UHF broadcast spectrum, particularly to provide wireless broadband services on a secondary or unlicensed basis. However, as regulators reallocate UHF spectrum released by the digital switchover to new services requiring a high degree of licence certainty (e.g. cellular networks) there will be incompatibilities between the rights of the new licensees and those of unlicensed white space users. What becomes of entrenched secondary usage rights if broadcast spectrum is reallocated to telecommunications and re-licensed on far more exclusive conditions than those currently prevailing for white space devices operating on a secondary basis to broadcasting services? Wide-spread deployment of white space devices could seriously complicate the reallocation of UHF band primary services from broadcasting to higher value users. This article considers Australian regulatory arrangements in light of this issue and suggests licensing reforms required to manage competing white space usage rights in the future. INTRODUCTION There has been increasing interest in telecommunications use of white spaces in the UHF bands that have traditionally 1 Contacts: Ben Freyens, assistant professor, Department of Economics, University of Canberra, ben.freyens@anu.edu.au. The views presented in this paper are our own and are expressed as private individuals. These views should not be assumed to represent the views of our respective institutions. been used for television broadcasting. In more and more countries this interest is fuelled by the now inexorable move towards digital terrestrial television broadcasting, the consequential and looming end of analogue terrestrial television broadcasting, continuing growth in internet usage and increasing demand for wireless broadband access. In the United States, the Federal Communications Commission (FCC) has established regulatory arrangements for white space devices and the UK s spectrum regulator and communications competition authority (Ofcom) is in the final stages of developing white space arrangements for the UK. However, emerging scenarios in digital switchover policy are challenging these developments by implicitly earmarking additional portions of the UHF band for purposes other than broadcasting in the longer term: namely mobile phone networks and wireless broadband services in the 10 to 15 year timeframe. In such a context, there is a risk that enabling the widespread deployment of white space devices in the UHF bands on a secondary basis will compromise the ability of regulators to achieve higher value use of the UHF band in the medium to long term. In 2009, one important and emerging scenario for the UHF band was the complete cessation of terrestrial television broadcasting in the UHF band. This development was foreshadowed in Finland [1], studied by the European Union and the subject of a legislative proposal in the United States. If white space devices are allowed in the UHF band, their widespread use could seriously constrain reallocation of more of the UHF band from broadcasting to higher value uses such as telecommunications should there be a digital dividend 2.0 in the year time frame. This would particularly be the case if the regulatory requirements for and the technical characteristics of white space devices are based on the assumption that the UHF band will continue to be used for digital terrestrial television. 1

3 Because of the significant differences between broadcasting and telecommunications use of the spectrum, white space devices capable of successfully operating on a secondary basis in a broadcasting environment may have little or no capacity to operate in a telecommunications environment without causing harmful interference or suffering from degraded performance and capacity. Alternatively, and more optimistically, the regulatory regime for white space devices could incentivise the development of white spaces devices with technical characteristics that enable cooperative sharing with telecommunications services. In a best case scenario, white space devices operating on a secondary and ad hoc basis would collaboratively operate in conjunction with telecommunications networks deployed on a planned basis by network operators using advanced technologies to provide services such as mobile broadband access. In this scenario, the deployment of white space devices in the UHF band in the short term could allow early realisation of the telecommunications potential of the UHF band and lead to increased producer and consumer benefit in the medium to long term. In this paper we discuss the regulatory requirements and the licensing structures better suited to the realisation of this objective the establishment of forward looking regulatory arrangements that will help enable a commercially viable and economically efficient transition of the UHF band from digital terrestrial television services to digital terrestrial television and secondary telecommunications usage and, finally, to high value telecommunications use. A first section describes the most commonly encountered types of white spaces and white space-using devices. A second section describes radiocommunications licensing arrangements for spectrumusing services in Australia. A third section describes proposals for a licensing regime allowing secondary unlicensed usage in private spectrum spaces (these spectrum spaces are typically used for mobile phones in Australia but the existing regulatory set-up does not allow secondary usage by any device). Finally, a fourth section evaluates this proposition with regard to the entrenched rights it might confer secondary unlicensed users, particularly if more of the UHF band is ultimately to be reallocated from broadcasting to higher value services. Some final comments conclude the paper. WHITE SPACES TV WHITE SPACE AND WHITE SPACE DEVICES TV white spaces (TVWS) are those channels that have been allocated for terrestrial television broadcasting but which have not been assigned to the provision of television services in a particular licence area (a more expansive definition would assert that TVWS also exist in channels that have been allocated to the provision of broadcasting services in licence areas but, for the purposes of this discussion, we limit our consideration of TVWS to channels that have not been so assigned). TVWS arise for three reasons. The first was the need for guard spaces between analog TV (ATV) services in the same licence area. If ATV services in the same licence area operated on immediately adjacent channels, the result would be mutual interference between the two services. Consequentially, planning for ATV services typically provided for a vacant channel (a guard space ) between ATV services in the same licence area. Because of the superior performance characteristics of digital terrestrial television technologies, the need for guard spaces between DTV services in the same licence area can be significantly reduced or eliminated. TVWS also arise from the need for geographic separation between TV services that are in different licence areas but are broadcasting on the same channel. Regardless of whether planning for TV services is noise-limited or interferencelimited, there will be areas where the channel is unable to be used for TV services (if a noise-limited planning model is used, the TVWS will typically be larger). Geographic separation occurs in both ATV and DTV planning and deployments. Finally, TVWS arise in areas where channels are not allocated to broadcasters for TV services, either because of the limited supply of broadcasting services (because only a small number have been authorised or deployed) or because there is limited demand for broadcasting services (typically because of low population density but more commonly because of the increasing range of technologies that can be used to deliver broadcasting services). In this context, TVWS occur regardless of whether ATV or DTV technology is in use. A device, which opportunistically uses these available channels, is commonly referred to as a white-space device (WSD). WSDs have so far come in two types: (i) symbiotic devices, which broadcasters have long tolerated, and (ii) invasive species, which have acquired secondary (unlicensed or class licensed) rights against the wishes of broadcasters through controversial regulatory decisions. SYMBIOTIC WSD DEVICES Despite the controversy surrounding recent proposals for WSD, there is a long history of radiocommunications devices that provide non-broadcasting services co-existing with broadcasters in TVWS. We have chosen to describe these precursor devices as symbiotic WSD because their ability to share successfully with broadcasting services was without doubt and based on compliance with a small set of relatively simple rules that were not controversial and which did not require advanced technologies to be implemented. From a regulatory perspective, even though symbiotic WSD were uncontroversial, their use was often, but not always, 2

4 based on tolerance rather than legitimacy. Wireless microphones used for Program Making and Special Events (PMSE) are an example of symbiotic WSD that have attracted a high profile as a result of the loss of their ecological niche unused guard channels between ATV services in heavily populated areas where PMSEW activities often occur. Wireless microphones are mostly used by stage performers (in concerts, in sports stadium, in mega-churches, etc.), but also by TV performers (e.g. reality shows), using idle television channels in given locations. In a common scenario, wireless microphones operated in the UHF band but were able to be programmed to operate on a range of channels. The channels chosen depended on the particular area where the microphones were to be used. This approach relied on the avoidance of channels that had been assigned to TV services in a licence area (for some time, an automated version of this approach was proposed for what we have characterised as invasive WSD ). Although the wireless microphones were not cognitive in the sense proposed by Mitola, they were operated in a cognitive fashion as their operators determined the idle channels that they could safely operate in (thereby able to be characterised as overlay signal devices). At the same time, wireless microphones are quite low power compared to terrestrial television transmissions and operate below the noise floor of ATV services in adjacent channels (and are thereby also able to be characterised as underlay signal devices). Depending on the service, the band and the country s regulatory framework, secondary PMSE usages of TVWS were managed under different types of licensed or unlicensed regimes. For example, in Australia as in the UK and elsewhere in Europe, the use of wireless microphones for PMSE usage in white space is licensed. In the US however, wireless microphones operating in TV white space have been floating in something of a legal limbo. Officially part of the Broadcast Auxiliary Service (BAS), they are theoretically subject to licensing. However, due to the overlay/underlay nature of the equipment, interferences have been rare, mild and have proved impossible to detect in real time anyway. Consequently, licensing requirements never saw much enforcement by the FCC and a well-funded corporate media constituency which has, now become politically difficult to disenfranchise, has emerged. To a large extent, this constituency was not perceived as harmful and quietly tolerated by broadcasters (perhaps because one important use of wireless microphones is to provide content for television broadcasters). For many years, the two services peacefully co-existed on licensed broadcast spectrum. The status-quo was challenged in 2008, when the FCC signalled that BAS devices would no longer be allowed to operate in the 700 MHz bands (which of course they were never authorised to do in the first place) due to the reallocation of that band to telecommunications services by way of auctions in February-March INVASIVE WSD SPECIES The successful occupation of TVWS by symbiotic PMSE devices was one factor that led to increased interest in the exploitation of TVWS by other services and technologies, again on an underlay / overlay basis 2. We describe this second generation of WSD as invasive WSD because their ability to share with broadcasting services was strongly contested and their operation depended on the use of advanced technologies to implement a significantly more sophisticated set of rules (and thus operating behaviours) than symbiotic WSD, The first waves of invasive WSD were proposed to work on an underlay rather than overlay basis. In 2002, the FCC amended its Part 15 rules to permit the unlicensed operations of some services using ultra-wideband ("UWB") technology[2]. Ultra-Wide Band (UWB) was a relatively new communications technique that relied on the development of integrated circuits with high computing capacity, low power consumption and small size. UWB devices transmit at extremely low power across very large bandwidths (hence the name) and thus transmit across a number of bands used by a wide range of services. The power density (power per MHz) of UWB devices is so low that the proponents of UWB technologies argued that they could not cause harmful interference to other services using more traditional technologies that operated at higher powers in narrower bandwidths. Broadcasters, along with many other established users of the spectrum, did not accept these arguments and had significant concerns about the potential for UWB devices to cause harmful interference to their services. Ultimately, the use of UWB has been allowed on a limited basis in a number of bands in various spectrum-reforming countries including the US, the UK and some Continental European nations. The 2002 FCC decision, followed in 2007 by similar decisions in the UK [3], in the EU [4] and in the Asia-Pacific region explicitly authorised the usage of UWB devices in TV broadcasting bands and thus in TVWS. Australia has authorised the use of ground penetrating radars that use UWB technology but which operate at frequencies above 2 GHz 3. In opposition to their relatively benign approach to PMSE services, it is fair to say that traditional broadcasters were very wary of UWB technology and have successfully lobbied their respective regulatory authorities to limit the range of frequencies it can use. Consequently, and considering that the UWB decision was not specific to TVWS in the first place, broadcasters and other incumbents eventually won the day and 2 Other factors include increasing sophistication and reduced cost of radiocommunications technologies and increasing demand for mobile communications services. 3 Note that in the 2002 FCC decision, only ground breaking radar UWB applications were authorised to operate under 960MHz. All other UWB devices were instructed to operate above 1.99, GHz, 3.1 GHz and higher frequencies. 3

5 simmering tensions over the matter of secondary usage of TVWS by UWB WSDs somewhat lapsed over time. Since then however, another debate has emerged with the FCC s decision to open up TVWS channels to cognitive radio technologies on an unlicensed basis (i.e. overlay rather than underlay technologies) to provide wireless broadband access. For instance, one early FCC suggestion included the use of GPS receivers in all invasive WSDs in conjunction with a database that contained details of all TV stations broadcasting in any given geographical area (essentially an attempt to automate the sense and avoid approach that was so successfully used on a manual basis with symbiotic WSD such as wireless microphones). Pressure to allow secondary use of TVWS intensified with increasing concern about the digital divide, including the failure of well-publicised efforts by municipalities to use WiFi technologies in the 2.4 and 5.8 GHz bands to provide ubiquitous access to the internet and increasing recognition that the propagation characteristics of the UHF band were far better suited to provide wireless broadband access. Unsurprisingly, the next wave of invasive WSD were intended to use TVWS to provide wireless broadband access. The National Broadband Plan unveiled by the FCC in March 2010 identified TVWS as an ideal input to provide broadband services to rural and remote communities. In particular, TVWS was identified as ideally suited to meet the shortfall in middle mile infrastructure in rural areas. Earlier, in 2008, the FCC famously agreed to open up TVWS for use by invasive WSD on an unlicensed basis. This decision was strongly opposed by the TV broadcasting and wireless microphone industries which teamed up to defend their previous regulatory and quasi-regulatory arrangements. Broadcasters again argued that using this portion of their licensed spectrum would interfere with the reception of their television broadcasts by consumers. In February 2009, the National Association of Broadcasters asked a Federal Court to wind down the 2008 FCC's authorization for TVWS usage by invasive WSDs. The case built upon the argument that the testing of white space sensing devices had not been thorough enough. Initial tests performed by the FCC in early 2008 showed that portable, unlicensed personal devices operating in the same band as TV broadcasts could indeed cause interference. The FCC subsequently agreed on some device restrictions, including using geo-location technology to allow invasive WSDs to compare their location against an established database of broadcast services. The FCC stressed that test devices using a combination of spectrum sensing and geo-location managed to successfully identify all occupied TVWS channels. Invasive WSDs that did not incorporate geolocation capabilities would be considered for authorisation on a case by case basis and have to submit to a rigorous application process for FCC certification. By the third quarter of 2010, little had happened since the FCC s 2008 decision. The deployment of invasive WSD in TVWS appeared bogged down by uncertainties on future spectrum allocation in TV bands, uncertainties about the certification of spectrum-sensing technologies intended to identify TVWS (idle or vacant channels), and little progress on the establishment of a system of geo-location facilitated database consultations.. DIGITAL SWITCHOVER AND TVWS So far, so good. If the FCC and other regulatory agencies see fit to enable the co-existence of broadcast services and underlay-overlay wireless devices, the regulatory framework needs little more than a standard secondary usage easement for unlicensed usage such as commonly found for many bands in ITU-R allocations, including specification of the rules that precisely establish the TVWS niche that is to be inhabited by invasive WSD. Alternatively, regulators could specifically reallocate TVWS, either in whole or in part, from broadcasting to unlicensed services as was done on ISM and UNII micro-wave bands. If broadcast spectrum is indeed large enough to accommodate both types of services or tolerate these kinds of subdivisions then the regulatory choices are relatively simple. These choices are however more complicated if one factors in uncertainty about the future use of that part of the UHF band that is being used for DTV after digital switchover. In the US, digital switchover enabled the reallocation of the 700 MHz band. Australia has announced that it will also have a digital dividend in the 700 MHz band while countries in the European Union are aligning around a smaller digital dividend from 790 to 862 MHz. In these countries the digital dividend has already been, or expected to be allocated predominantly to advanced mobile cellular and mobile broadband networks using technologies such as HSPA, WiMAX or LTE. Until recently, it appeared that the situation for DTV (and thus WSD, both symbiotic and invasive) would stabilise after digital switchover with a habitat that was reduced in size but still ecologically viable for both the primary service and secondary users. But increasing interest in the potential for further reallocation of UHF spectrum from broadcasting to other services which we describe as a digital dividend 2.0 has emerged since 2008 when the Finnish national plan of action identified that the achievement of high speed broadband by 2015 would allow consideration of the future of terrestrial DTV by In August 2009, the European Commission received a report on exploiting the digital dividend that identified two options for making more spectrum available for wireless broadband or other nonbroadcasting purposes in the European Union. One option was for reallocation of MHz which would be more consistent with the American and Australian digital dividends but the second option was to completely clear DTV from the 4

6 UHF band to realise a digital dividend from MHz. While the report indicates that neither of these options is realistic in the short term, it identifies that they may well be achievable in the medium (beyond 2015) to long (beyond 2020) term. Finally, in December 2009 the FCC issued a public notice that sought data on future use of spectrum used for terrestrial television broadcasting, including the impact of reallocating more spectrum a digital dividend 2.0 away from DTV [5]. Further reallocation of UHF spectrum from broadcasters to other uses in these timeframes clearly has major implications for regulators (as well as industry and consumers). One of those implications is that regulatory frameworks that allow the use of invasive WSD must be considered very carefully. This is because the widespread use of invasive WSDs is likely to limit the ability of telecommunications operators to successfully deploy high capacity networks in spectrum that has been vacated by broadcasters. This is, in turn, a consequence of the different technical characteristics of broadcasting stations and telecommunications networks. Broadcast services such as DTV are characterised by the use of a small number of carefully planned sites that transmit at extremely high power (kilowatts or even megawatts) and use a limited number of channels to provide services to a relatively large area. Broadcast infrastructure is typically stable over time as an increase in the number of receivers (TV sets) in the licence area does not normally require an increase in the number of transmission sites. In contrast, telecommunications networks involve the deployment of a much larger number of base stations, typically on a cellular basis to maximise frequency reuse, and which operate at power levels well below one kilowatt. Base stations both transmit to and receive signals from user devices. Importantly, an increase in the number of user devices in the licence area often results in an increase in the number of base stations as network operators increase the intensity of use of the spectrum allocation (which is typically the limiting resource in overall network capacity and performance). In summary, broadcasters typically operate from a small number of sites that transmit at very high power with a low rate of change in transmitter locations and transmission frequencies. Telecommunications networks typically operate from a much larger of sites that transmit and receive at low power. Network deployments change quickly with increasing numbers of base stations with frequent changes in frequencies of operation for individual base stations as a result of the ripple effect that new base stations can have on the frequencies used by base stations in their vicinity. These contrasting technical characteristics mean that invasive WSD that operate successfully in a broadcasting environment may cause harmful interference or suffer degraded performance if the primary use of spectrum is reallocated from broadcasting to telecommunications. As a result, there is a significant risk that the widespread deployment of invasive WSD in a broadcasting environment may deter or frustrate the further reallocation of the UHF band from broadcasting to other services. This is because prospective new users of the spectrum may be reluctant to bid for licences (or pay the prices sought by governments) and may be constrained in their ability to deploy new networks because of interference from invasive WSDs that turn out to be harder to dislodge from their ecological niche than broadcasters. While broadcasters have an impressive record of achieving favourable regulatory outcomes from government, they are ultimately businesses that comply with legal requirements and regulatory obligations. The majority of citizens are also lawabiding but, as consumers, may not recognize, or may be reluctant to accept, that the highly functional wireless device in their house that has operated flawlessly for several years is an invasive WSD that may need to be modified or replaced because of the reallocation of additional UHF band spectrum in a digital dividend 2.0 that is intended to further improve the availability of spectrum for wireless broadband access. To further complicate matters, network operators have increasingly enjoyed more flexible usage rights than broadcasters (in their ability to deploy new technologies and offer new services) and, as wireless telecommunications services have become increasingly ubiquitous and more important, sought more stringent licence conditions to protect their large investments in network infrastructure. If these emerging scenarios for a digital dividend 2.0 are combined with the fact that suitable arrangements for PMSE have yet to be finalised in countries that are in the process of implementing digital dividend 1.0, we can only wonder what would happen if regulatory authorities did not have to deal with a relatively small PMSE community using symbiotic WSD but a host of citizens enamoured of the invasive WSD that provide them with crucial connectivity to, and improve the functionality of nationally deployed high speed broadband networks. Put more concretely, while regulators typically have clear legal authority to vary or revoke the unlicensed or class licensed regimes that are often used to authorise WSD, achieving compliance can be a significantly more challenging problem because of the need to change behaviour at the consumer and residential level rather than at the industry and supply level. The resources required to remove large numbers of consumer devices potentially millions from the UHF band in order to achieve a digital dividend 2.0 band would be substantial. Significant expenditure by the regulator and incoming licensees would likely be required to support a compliance program over several years with risks to incoming licensees ranging from quality of service (because of interference to newly installed networks from incompatible WSD) to brand management (because of the potential for 5

7 adverse consumer reaction should the regulatory or licensees adopt a an aggressive approach to enforcement). In these circumstances, Hhow would a regulatory agency keep the necessary flexibility to prioritise the rights of new licensees and enable invasive WSD to successfully adapt and contribute an environment that is making a step change from high power broadcasting services to low power telecommunications services? To attempt an answer requires a formulation of the current regulatory arrangements for broadcasting, network operators and unlicensed devices. A full review of these licensing structures by country of interest (US, UK, Canada, Australia, New Zealand, Japan, Singapore, etc.) is well beyond the scope of this paper. Instead, we briefly review the regulatory instruments in Australia where broadcasting services are authorised by apparatus licenses 4, network services are usually licensed through a property rights framework known as spectrum licences, and unlicensed usage is regulated through class licences, with all of these different types of radiocommunications licence issued under the Radiocommunications Act LICENSING REGIMES Licenses are renewable access rights issued by the Australian Communications and Media Authority (ACMA), the Australian regulator. The licences specify a variety of regulatory arrangements, mainly to govern interference management. In Australia, all broadcasting and radiocommunication licensing regimes are regulated through two acts of Parliament; the Radiocommunications Act 1992 (the Act) and the Broadcasting Services Act 1992 (for our purposes, the Act is of principal relevance and the majority of the following discussion refers to that Act). The legislative framework flowing from the Act (which draws heavily from ITU regulations) fully authorises and defines the specifications and operations of three categories of licensing regimes for radiocommunications; apparatus, spectrum and class licensing (somewhat imperfectly reflecting the so-called trichotomic approach of command and control, property rights and open access ). These regimes set out the rights and obligations of users. They differ in many respects, but they also have common denominators. For instance, they all impose a minimal set of core specifications about frequency, bandwidth, area, power and emission types, although the way these conditions are integrated in practice vary among these licensing regimes. In general, apparatus and spectrum licensing have more in common than class licensing. Both licences are typically used 4 Apparatus licences are issued under the Radiocommunications Act. Where broadcasting services are concerned, the apparatus licences are issued after the services are planned under the Broadcasting Services Act. to provide exclusive access rights, can be auctioned, leased or traded and are subject to regulatory approval for licence renewal - though on very different terms. By contrast, class licences operate on an open and shared access basis. There is no exclusivity in usage and for that reason it is regularly referred to as the public park or open access regime. It is probably the simplest approach to assigning and allocating spectrum, both for regulators and users. A class licence sets out some minimal operational conditions. These conditions consist of (i) technical parameters somewhat akin to the basic technical conditions of apparatus licences (operation band, maximum transmitting power, types of device and emissions), (ii) requirements of equipment compliance with standards, with the onus generally on manufacturers, and (iii) geographic deployment constraints (where relevant). Operation of a device under a class licence does not require that an application be made to the regulator and a class licence is not issued to an individual organisation (although the ACMA is able to impose conditions about the class of user as well as the class of the device). As such, Australian class licences are the equivalent of unlicensed approaches used in other countries. Since class licences are not issued to individuals, the licence conditions are not applied nor tailored to individual users (as is the case e.g. through frequency assignment certification under apparatus licensing, and through device registration under spectrum licences). Unlike apparatus and spectrum licences, the term of a class licence is not limited by the Act although it is open to the ACMA to revoke or amend class licences after satisfying its statutory obligations to consult about changes. Class licensing is a highly efficient regime in cases where the conditions are appropriate for the use to which the licensee wants to put his/ her licence [6]. On the other hand, class licensees effectively operate on a secondary basis and are not authorised to interfere with the transmissions of other (apparatus and spectrum) licensees or provided protection from interferences generated by other services. For this reason, this licensing regime is generally not popular with larger radiocommunications operators, such as telecommunications carriers, whose business model and reputation may largely depend on maintaining a minimum guaranteed level of service quality. Hence as the services and devices authorised under class licences must present a low potential for interference, they are most often only used to authorise for short-range, low-power applications (however, class licences have been used to authorise earth stations in several frequency bands which do operate using high powers but which, importantly, have a low potential for interference because of the coordination required for satellite networks). Some bands, such as the 2.4 (ISM) and 5.2 GHz (UN-II) bands are specifically set aside for class licensing, but most class licences operate as non-interfering secondary usage easements in apparatus licensed bands (e.g. 6

8 symbiotic WSD such as biomedical telemetry devices that operate in TVWS). The class licence of most interest to the White Space debate is the Radiocommunications (Low Interference Potential Devices) Class License 2000 (the LIPD Class Licence - pronounced lipid ) which governs the operation of tens of thousands of low power, short-range radiocommunications devices using cutting edge technologies such as the IEEE standard (Wi-Fi) and Ultra-Wide Band (UWB) services. LIPD-licensed devices are ubiquitous, operating on a disparate array of frequency bands such as broadcasting bands or radio navigation bands (but never under mobile phone bands). They operate mostly with secondary usage rights over apparatus-licensed portions of the spectrum, but are not authorised in spectrum-licensed spaces where decision regarding secondary usage rights are entirely to the discretion of the owner 5. They are also found in specifically allocated spectrum bands such as the ISM and UNII bands. The common and divergent features of Australia s three licensing regimes are further discussed in [7], [8], and [9]. REGULATING UNLICENSED WHITE SPACE SERVICES AFTER SPECTRUM RE-ALLOCATION Unlicensed secondary usage is commonly encountered on licensed bands characterised by a relatively mild degree of service exclusivity. For instance, there are various illustrations of unlicensed WSDs operating on a secondary usage basis in the US, ranging from PCS cellular services 6 in the 1.9 GHz band, to a variety of short-range, indoor UWB applications such as imaging systems (surveillance systems, groundpenetrating radars, etc.), precision vehicular radar and other personal networking and communication devices mostly using bands between 3.1 and 10.6 GHz. In 2007 EU countries also authorized the use of unlicensed UWB technology on bands already licensed for other services and technologies. In Australia, a secondary usage regime for WSDs corresponds to a situation in which the regulator the ACMA would be allowed to issue class licenses (aka unlicensed spectrum) in the same spectrum space that is occupied by apparatus licences (e.g. as currently held by broadcasters) or spectrum licences (e.g. as currently held by 3G and WiMAX network operators). While the former is commonly encountered, such as symbiotic WSD operating in TVWS and sharing the UHF 5 The only exception to this rule relates to the situation where a class licence is in place before a frequency band designated or reallocated for spectrum licensing. While the class licence would continue in force, the ACMA would be unable to vary it after a designation notice or reallocation declaration was made that included the frequency ranges in the class licence. 6 When new PCS systems were allocated in the 1.9 GHz band, the spectrum was still occupied by private microwave systems. Yet, PCS licensees were quickly able to operate on the band, rolling out their networks by coordinating with incumbents and managing interference prior to incumbent relocation. In practice, PCS licensees effectively operated on the band on an informal secondary basis for some period of time. band with apparatus-licensed broadcast services, the Act does not permit the latter. The current rule only allows that if an existing class license is used in a band over which a spectrum license is auctioned, the class license arrangement remains unchanged, but this theoretical situation has never been seen in practice. This means that if TVWS spectrum was ever to be sold as private spectrum space and acquired by a network operator, the regulatory authority would be faced by an unusual dilemma regarding the respective usage rights of each user. If unresolved, the uncertainty would seem likely to reduce the value of a spectrum space to prospective acquirers. This standoff is part of a decade-long property right vs. shared access dilemma gripping the policy debate in the US and elsewhere [10], [7]. Proposed solutions have converged towards an easement regime, in which primary licensees ( owners ) have clear broadcast rights but secondary users (unlicensed or differently licensed users) may use the band so long as they never purposely interfere with the owner s transmission and reception rights. Compliance is enforced through identification signals and compensation schemes for owners-incurred monitoring costs [11], [12]. The idea of allowing non-interfering easements or at the very least some forms of co-existence formula for other users within spectrum-licensed (i.e. private property) spaces was proposed by the Australian Communications Authority (the ACA), which preceded the ACMA. In a submission to a 2002 Government inquiry, the ACA suggested allowing noninterfering class licensed services into spectrum spaces, which is the matter at stake for continued use of symbiotic WSD should TVWS be reallocated to telecommunications network operators. Given that class licences operate rather successfully on non-interfering conditions in apparatus licences bands, why would that option not be available in spectrum-licensed spaces as well? This was the question posed by the ACMA when it released a discussion paper in 2006 about a proposal to allow the authorisation of devices under class licences in spectrum designated for spectrum licensing. The initiative was concerned with the likely expansion of spectrum licences (and exclusion zones that would result for class licensing) at a time when new technologies needed larger and larger bandwidth to be experimented and/or deployed e.g. UWB applications such as ground-penetration radar and dynamic channel selection technologies (see e.g. [8] for further details). The prevention of easement opportunities for class licences (either directly or through ambiguity) is a particularly severe shortcoming of the current system of legal rules in Australia. The easement regime offers an important promise to alleviate spectrum congestion in some bands and satisfy un-met demand in others. More importantly still, and as surmised by numerous legal scholars, private property exclusion zones impose a large welfare cost to society by preventing or slowing the development, testing and deployment of cutting- 7

9 edge new wireless technologies, which require fast and easy access to specific spectrum bands [13], [14], [15]. A case of the tragedy of the anti-commons 7 was also in regulators minds. In the case of class licences, the tragedy of the anti-commons means that device operators would under the current legal provisions of the Act face Swiss cheese arrangements (to excise frequencies protected by s.36) in order to gain access to various areas of the spectrum whilst having to negotiate access with the owners of each spectrumlicensed space. Since many low power devices trade power for bandwidth, this situation is counterproductive and onerous both for class licensed device operators and band owners (who would face countless applications for third party authorisations) 8. Consequently, the ACMA suggested repealing section s.138 of the Act, explicitly allowing class licences into spectrum-licensed spaces in s.36 and including ancillary provisions into the Act to make statutory consultations about each easement proposal. Spectrum licensees strongly opposed such a move and it has not been pursued any further. Spectrum licensees were very concerned that they would suffer interference to their systems and argued it would infringe their property rights. One area of concern was the cumulative impact on noise levels by a large number of low powered devices operating in the same spectrum band, even if only one device would not produce detectable interference. Last year, the matter of secondary easement rights for class licences re-emerged once again in a Ministerial discussion paper over the definition of public interest criteria for spectrum licence renewal [17]. In the discussion paper, the Department of Broadband, Communications and the Digital Economy (DBCDE) alluded to possible easement regimes to the second generation of (re-issued) spectrum licences. The Department clearly foresaw the need to cater for co-existence plans for future technologies such as Ultra-Wideband and cognitive radio and to correctly anticipate future technological trends amongst unlicensed wireless devices. Why indeed keep class licence out of spectrum-licensed spaces when they have proved so effective at generating highly valued uses without interfering with the receivers of primary band users? In the meantime, and wherever possible, the ACMA has shifted the load of allowing high-demand class licensed services to apparatus bands (e.g. numerous UWB services such as imaging or ground-breaking radar under scientific licences), and to an extent this has worked well 7 The anticommons or hold up problem arises when there exists multiple rights to exclude access to a resource along with incentives for strategic behaviour [16] If spectrum property rights are held by more than one user, new technologies and applications may be held up (ie. barred from spectrum access) by rent-seeking behaviour [6], [10]. 8 Note that this is also relevant if class licensed operators want to exceed power or other conditions and wish to proceed by getting a third party authorisation from a spectrum licence holder. because the size of the total spectrum occupied by spectrum licences is still rather small, so the scope for inserting class licences as easements to apparatus licences is rather large. Yet, the ACMA will not be able to this indefinitely. If the portion of the total spectrum occupied by spectrum licences is called to grow, as is frequently proposed in Australia, the squeeze on new high tech services, such as operating in TVWS, will become unbearable. Recognising this challenge, the Government introduced legislation to amend the Act into Parliament in June 2010 [18]. The Radiocommunications Amendment Bill 2010 (the Bill) proposes several amendments of the Act in relation to spectrum licensing. Of those amendments, the most significant would be the amendment of section 138 to give the ACMA the power to issue class licences in spectrum spaces (whether established by conversion or reallocation) subject to a requirement spectrum licensees be protected from unacceptable interference. A new subsection 136(1A) is also proposed that would allow the ACMA to vary a class licence that existed before a spectrum space was established. The Bill passed through the House of Representatives in October 2010 but only after the Opposition expressed concern that the amendments to allow co-existence between class and spectrum licences did not provide enough clarity about what is or is not unacceptable interference and potential for adverse impacts on the value of the networks established by spectrum licensees. After an inquiry by The Bill was referred to the Environment and Legislation Committee of the Senate in November 2010, the Bill received Royal Assent and became law in December for inquiry with the Committee asked to report to the Senate in November REGULATORY REQUIREMENTS The Amending the Act to allow the ACMA to issue and vary class licences in spectrum spaces is a significant reform to the regulatory framework and one that holds out the promise of licensing arrangements that support the full range of spectrum management regimes available to the regulator[7], [9], [19], [20], and [21]. However, as demonstrated by the debate in the House of Representatives, there is some concern about how that ACMA will implement that regulatory framework when it comes to consider the potential for class licences to authorise devices in highly valued spectrum spaces. While this is an important issue, our interest is in a different and more general scenario the establishment of licensing arrangements for invasive WSD after digital dividend 1.0 that do not constrain the later realisation of an additional digital dividend 2.0. One approach to this challenge would be for the regulator to determine that the use of invasive WSD will not be allowed to continue to operate once broadcasting ceases to be the primary service and it is reallocated for other purposes. While this 8

10 approach may have some appeal, it suffers from some significant limitations. Consumer devices that are not tightly bound to particular networks and technologies will tend to continue in use even if the regulatory permission to operate them is withdrawn. If invasive WSD are able to flourish and thrive in TVWS, then they may prove to be a persistent feature of the spectrum landscape. Secondly, this risk may lead regulators to decide against authorising invasive WSD or to place stringent limitations on their use with consequential reductions on total welfare. Finally, and most importantly, this approach would forego the opportunity to create regulatory arrangements that maximised total welfare by developing technical frameworks that would allow invasive WSD to flourish and thrive in both broadcasting and telecommunications environments. We suggest that an alternative approach would be for regulators and industry to identify the technical and operating characteristics that would allow invasive WSD to successfully transition from broadcasting environments where there are a small number of high powered transmitters and where technology changes little over time, to telecommunications environments where there are large numbers of low powered transmitters and rapid technological change over time. Ideally, invasive WSD would be able to adaptively collaborate with telecommunications networks using advanced technologies. Importantly, there is time for regulators and industry to develop an understanding of the technical and operating characteristics that are required for optimal invasive WSD. This is because it seems likely that it will be 5 to 10 to 15 years before the realisation of a digital dividend 2.0 and that period of time is sufficient for the development of increasingly sophisticated invasive WSD and the consequential retirement of earlier generations of invasive WSD that will be sub-optimal in a telecommunications environment. Operations of WSDs in property spectrum owned by large communications carriers and other network operators raise a number of questions. What are the limitations in the Act if ACMA wishes to proceed with a bespoke approach and what sort of legislation would be needed? What type of current licensing models could be amended and how? Although apparatus licences are already conducive to a tailored licensing approach, spectrum licences by contrast are not. Spectrum licences currently constitute a very monolithic regime under the Act. They occupy large portions of spectrum in very exclusive ways. Although spectrum licences were designed as a tool to remove market barriers, the large spectrum-licensed spaces they control are too often dictated by the spectrum-guzzling technologies (such as 3G, and soon LTE) deployed on them. How could licensees be expected to subdivide and trade quantities of spectrum with smaller mobile broadband wireless services when they need the spectrum in a large amount to guarantee the workability of their technical frameworks? Under these conditions, the main alternative available to increase the yield of spectrum-licensed spaces is to allow non-interfering secondary usage such as by low-power, spread-spectrum and cognitive spectrum-sensing devices. Concretely, in an Australian context, this was would require achieved in December 2010 when that section s.138 of the Act was be amended to allow secondary usage rights for class licences within spectrum-licensed spaces. This will in order to improve the allocative efficiency of spectrum licences and enable secondary usage of TVWS by WSDs. CONCLUSIONS Digital switchover, and the consequential realisation of a digital dividend, has been an important focus of governments and regulators over the last decade. Digital switchover has either been achieved or is underway in a majority of advanced economies with significant economic, commercial and social benefits expected to result from the reallocation of valuable spectrum in the UHF band from broadcasting to telecommunications. The last decade has also seen increasing advocacy for, and interest in the use of TVWS in the UHF band spectrum that has been allocated to the broadcasting service but not assigned to a particular broadcaster by new generation white space devices invasive WSD that are intended to be deployed on a large scale but operate without affecting the reception of broadcast services because of their intrinsic ability to automatically adapt to their specific local spectrum environment. However, now that there is an emerging scenario of a second digital dividend in the medium to long term a digital dividend 2.0 we identify the potential for the widespread deployment of invasive WSD to impact adversely on the realisation of any additional digital dividend. This is because the broadcasting environment is characterised by high power transmitter operating from a small number of sites with little change over time while the telecommunications environment is characterised by a much larger number of transmitter sites that operate at lower powers and which change relatively quickly over time. White space devices capable of successfully operating on a secondary basis in a broadcasting environment may have little or no capacity to operate in a telecommunications environment without causing harmful interference or suffering from degraded performance and capacity. In this context, we set out the Australian regulatory framework governing the licensing operations of the three main players (or future potential players) in the TV White Space debate; broadcasters (governed by apparatus licences issued after detailed planning for broadcasting services), unlicensed wireless service devices (typically governed by the LIPD Class Licence) and mobile phone / mobile broadband 9