COMMENTS OF SPECTRUM BRIDGE INC. ON CONSULTATION ON A POLICY AND TECHNICAL FRAMEWORK FOR THE USE OF NON-BROADCASTING APPLICATIONS IN THE TELEVISION BROADCASTING BANDS BELOW 698 MHZ Publication Information: Canada Gazette, Part I - August 2011 reference number (SMSE- 0012-10). Introduction & Executive Summary 1. Spectrum Bridge, Inc. (SBI), one of the 9 original provisionally designated US Database providers, is pleased to provide comments and inputs to this filing. Spectrum Bridge has a long history of developing technology and deploying trials of the technology for TV White Space and, as of the time of filing, has successfully completed the FCC mandated 45 day trial of its solution, the last step to transition from provisional to commercially designated TVWS database provider. Spectrum Bridge is also actively involved in trials in the United Kingdom and Finland and is providing support for database driven trials in Singapore. 2. SBI believes that authorized shared access to spectrum by means of a policy manager (Database + Rules Engine) is the key to unlocking a vast amount of spectrum and innovation for the wireless industry. The use of such technology allows for very granular and timely adjustments to spectrum allocations and regulation. It is realistic to suggest that spectrum allocations can be done on the fly in future, leveraging the available technology, over areas as small as a football field in a matter of minutes. This is a very different paradigm to the static way spectrum is allocated and managed today. To that end whatever rules the Government of Canada chooses to implement today the rules can be adjusted to suit market conditions, available technology and future customer needs. For More Information on Spectrum Bridge White Space solutions please visit http://whitespaces.spectrumbridge.com/whitespaces/home.aspx For more information on responses provided to the questions asked please contact Peter Stanforth CTO Spectrum Bridge Inc. 1064 Greenwood Blvd. Lake Mary FL 32746 peter@spectrumbridge.com
Detailed Responses 3. Response to question 6-1: Unlicensed spectrum, such as in the 2.4GHz band, has become one of the biggest industry success stories of the last 20 years. The opening up of unlicensed spectrum in 2.4GHz led to the creation of successful technologies such as Wi-Fi and Bluetooth. Today more devices (computers, cell phones, video game systems, cameras, toys, etc.) are sold every year that operate in 2.4GHz than any other spectrum band in the world. This is a huge success, but also a potential future problem. Just as wireless carriers are looking for more spectrum as wireless Internet usage by smart phones grows exponentially, similarly the demand for unlicensed spectrum will outstrip supply. TV White Space represents a way to open up additional unlicensed spectrum for both existing and new customer usage models, while at the same time pioneering a new spectrum sharing technique, geo-location spectrum databases, that promises to allow more spectrum, both licensed and unlicensed, to be freed up to meet the ever expanding need for additional wireless Internet services. In particular, outside of the Urban areas around the US border a significant amount of TV White Space exists for meeting rural broadband requirements as shown in the diagram below 4. Response to question 6-2: Geo-location spectrum databases allow spectrum sharing in ways that have not been possible before, allowing many existing bands which may have incumbent users (TV bands, military, civil government agencies, etc.) to be shared with new users all while mitigating interference issues and allowing regulatory agencies real-time control in case of harmful interference or national emergency needs. SBI expects the TV White Space bands to be first of many frequency bands where geo-location spectrum databases can be used to benefit customers, industry and the regulator. Copyright 2011, Spectrum Bridge Inc., All Rights Reserved 2
5. Response to question 6-3: The majority of regulatory and standards organization efforts are focused on database dependent solutions. However this does not preclude the addition of spectrum sensing solutions in the future. In fact it is Spectrum Bridge s belief that the addition of spectrum sensing can be enhanced by a Database driven approach to Shared Access to Spectrum and that sensing radios can improve the effectiveness of the Database. 6. In the former case the database can advise a sensing radio where to look and what to look for, minimizing the processing overhead and energy use of the sensing radio. In the latter case the radio can provide feedback to the database about the actual RF environment permitting the Database to use more granular tolerance and allowance for interference than would be acceptable for a Database only approach. 7. Response to question 6-4: The basic performance rules are acceptable to ensure interference protection to protected entities. The FCC and Database Administrators in the US determined that in addition to minimum accepted standards for protection that all Database must meet, their needed to be a formal way for the Administrators to share information to ensure consistent operation. In many cases the Database Administrators chose to provide capability in excess of these minimum requirements. It is the belief of Spectrum Bridge that Industry Canada should specify what the database should do but not how. Different use cases and business models may evolve for the use of spectrum and allowing the radio vendors and Database administrators to determine how best to meet the requirements is best way to serve innovation and creativity. SBI would propose that there be some regulation of the Database Providers to ensure that they will continue to act responsibly and accurately based on the initial rules and any changes thereafter. The ability to create and maintain accurate protection for incumbent operations is complex and time consuming and the definition of minimum standards will stop devices and device owners from shopping for the most liberal interpretation of the rules. Further the regulation should require the database operators to take action to deal with any unintended interference and, where possible exclude rogue devices. 8. Response to question 6-5: There is no need, from a database perspective to place any arbitrary limitations on the type of white space device. Ofcom chose to describe a device by it s operation and the database has to protect incumbents accordingly. This allows for flexibility that may be appropriate for Canadian operation particularly in rural areas. For instance the database can adjust the buffer between a device and an incumbent operation on a sliding scale allowing for significantly higher powered white space devices in remote rural areas where coverage may be the basic economic criteria. 9. Fixed or mobile operation, from a database perspective is simply a function of how often a device will have to query for a channel allocation. Copyright 2011, Spectrum Bridge Inc., All Rights Reserved 3
10. Response to question 6-6: The basic concept of white space operation is that the device will opportunistically use spectrum under some basic control from a database. To the device a channel is either available or unavailable. The device does not need to know why a channel is unavailable. Under US rules all devices are treated equally and so all get the same channel allocations. This is not a technology requirement. It is reasonable that Canadian operation could continue to support licensed or Licensed lite applications using TV White Space and the database. In this case the database would make some additional determination to decide if a channel was to be made available to a device. It could be as simple as a serial number or similar ownership identification. Thus devices that were pre-designated to use the licensed channel would get permission from the database in response to a query whereas a non-designated device at the same location would not get permission to use the channel. This is a simple extension of the concept of fixed and personal/portable device types. 11. Response to question 6-7: The US rules for the use of white spaces have defined a generally useful ecosystem and basis for harnessing the utility of TV white spaces. However, the US rules may not facilitate the most efficient use of existing technology and applications most useful in Canada. For example, a one watt conducted emissions limit (4W EIRP), may not be capable of cost effectively meeting the needs of broadband customers in very rural environments. Furthermore, establishing a very conservative one size fits all emissions limit will preclude many existing radio platforms and technologies from being using in white space applications, increasing costs and extending time to market (see response to 6-13 below). The flexibility and power of a cloud based spectrum management process has been proven capable of implementing flexible and comprehensive rules and policies that can accommodate a wide range of existing technology, while ensuring adequate protection to incumbent users. 12. Response to question 6-8: The co-channel and adjacent-channel separation distances relative to the TV protected contours specified in Table 6.2 are conservative and serve as a reasonable starting point for interference protection for TV receivers. However, establishing fixed values places unnecessary operational constraints upon the TVWS ecosystem. Separation distances can readily, consistently and accurately be applied as part of the realtime channel determination and allocation process performed by a TVWS database. 13. More specifically, a well characterized, empirically derived path loss model such as the Hata-Okumura model (proposed by Ofcom) can be used to derive variable transmit power as a function of antenna height and separation distance. Coincidentally, the values in this table can also be derived via a Hata-Okumura model derivative. 14. Response to question 6-9: There is no inherent conflict between the operation of RRBS and white space. RRBS could simply be designated as licensed users of the spectrum and they can be protected in the database. However the license rules should be stricter in that it should not be possible for an entity to simply acquire all the white space and there should be some requirement to demonstrate that the spectrum is actually being used, to maintain the Copyright 2011, Spectrum Bridge Inc., All Rights Reserved 4
license. As noted there are also impediments to the success of RRBS that a database solution could address. There are multiple ways for these RRBS solutions to be managed by a shared access database solution. In addition to treating them as licensed entities they could be afforded some priority access to certain channels or their co-existence with low power white space devices could be managed by the database. 15. Response to question 6-10: The FCC rules designate 2 channels for exclusive use by wireless microphones. In addition because the rules restrict the operation of white space devices there are usually several more channels that, while not exclusively reserved for microphones, can be used by microphones without fear of interference by a white space device (show example from SMWS). In addition the FCC rules provide for unlicensed microphone users to justify, on a case by case basis, the need for licensed like operation. The Database solutions developed for the US provide for protection to both licensed and unlicensed microphones either by channel allocation or license protection, as shown in the diagram below. 16. Response to question 6-11: The database solution can accommodate any and all of the proposed options. However the database does allow for use of wireless microphones to be captured, in terms of location and time, which could form the basis of a coordinated approach to the registration or use of channels in the future. 17. Response to question 6-13: Ofcom (United Kingdom) and the Electronic Communications Committee (ECC) within the European Conference of Postal and Telecommunications Administrations (CEPT) have proposed rules that afford greater flexibility in how white Copyright 2011, Spectrum Bridge Inc., All Rights Reserved 5
space devices meet the criteria for protection of TV broadcast receivers from interference. This is accomplished by allowing devices to transmit at varying power levels, as a function of out-of-band emissions and distance to protected entities. The algorithms and functions proposed in this model are based on broadly used data and empirically verified models. 18. The level of sophistication and technical complexity required to implement the Ofcom system is no more complicated than the system required to support the FCC s rules in the US. Furthermore, the inherent nature of a database architecture, operating in real-time, allows regulators to adjust methodologies - if, where, and when necessitated. Spectrum Bridge has implemented systems for both domains. 19. Ofcom s proposed channel availability model already incorporates adjacent channel protection. As previously mentioned, Ofcom s proposal to accommodate devices with varying out-of-band emissions profiles lends itself as a very practical approach that will accommodate a wide variety of existing, off-the-shelf technologies. These technologies include OFDM based modulations such as WiFi and WiMax, which may otherwise be precluded from use. 20. Spectrum Bridge re-affirms Industry Canada s position that the capability inherent in a cloud based spectrum management database will allow Industry Canada to allow for real time control of interference, modify technical and operating requirements quickly and simply by modifying how the database functions and as experience is gained, administer a flexible approach to the development of upfront technical rules that would ensure protection of other radio systems from interference, improve access to a finite supply of radio spectrum. 21. Response to question 6-14: Yes, the benefits outweigh the risks, as the flexible database approach minimizes the opportunity for interference and provides a real-time method for addressing issues. Multiple trials in the US and EU have been able to demonstrate the ability to deploy useful and economical applications using White Space without causing harmful interference to incumbent operations. As the technology and the knowledge of use cases improves over time the database approach allows the fine tuning of regulations to ensure continued co-existence between the primary (incumbent) users and the secondary (White Space) users. Over the course of the last 2 years Spectrum Bridge has deployed, together with a number of well known industry partners, trials around the world. In addition to being used to validate proposed regulations and technologies these trials have demonstrated the capability for TVWS to support a diverse range of applications ranging from Broadband Access to Smart Grid in rural areas and TeleMedicine, Smart City and Enhanced Location Services in urban areas. Copyright 2011, Spectrum Bridge Inc., All Rights Reserved 6