بهره برداری از فضای سفید تلویزیون از طریق یک پایگاه داده جغرافیایی محل دو پارلمانی

The exploitation of TV white spaces can meet the increasing demand for spectrum resources and create opportunities for deploying a variety of wireless services in a flexible manner. However, uncertainties from technologies, business models and regulatory policies hinder the take-off of TV white spaces exploitation. This paper proposes a bicameral (or two-chambered) geo-location database, which allows/supports both free and paid access to the TV white spaces: i.e., one chamber supports free access through opportunistic or geo-location database access; and the other chamber supports paid usage through secondary spectrum trading. Consequently, four technological scenarios for the acquisition of TV white spaces emerge, namely: sensing only, joint sensing and geo-location database access, geo-location database access only, and broker based secondary spectrum trading. An analysis of these scenarios is performed based on a theoretical framework for emerging technology evaluation while considering technological, business models and regulatory dimensions. The analyses show that free and paid access to TV white space complement each other; and that despite considerable infrastructure costs, the bicameral geo-location database is positioned to create viable TV white spaces exploitation value chains; hence have the most optimal technological, business and regulatory prospects.

Technological innovation for new entrants in the wireless services market such as machine-to-machine (M2M) communications, broadband Internet access, etc.; and capacity extension for current operators are the main drivers for the need of additional spectrum. TV white spaces offer a very rare opportunity to meet this demand. TV white spaces are spectrum frequency bands unused by the Digital Video Broadcasting—Terrestrial (DVB-T) systems, interleaved in both frequency and space. The exploitation of TV white spaces in different countries, however, with the exception of the USA and the UK, has not yet taken-off. It has been grounded by uncertainties regarding enabling technologies, potential business models and regulatory policies. The protection of incumbent systems is the main concern when developing cognitive radio (CR) networks operating in TV white spaces (Deb et al., 2009, FCC, 2010 and Peha, 2009). DVB-T systems and professional wireless microphones or PMSEs (Programme Making and Special Events) are considered to be incumbent users of the TV spectrum bands. PMSEs' owners are concerned that the exploitation of TV white spaces by CRs may harm their services, which are vulnerable to interference. Moreover, are DVB-T operators willing to share their bands? Most likely they are not, neither do they have incentives to improve their technologies to make sharper filters and increase the efficiency of UHF bands usage. Therefore, factors that will influence the alignment of incumbents to favor the sharing of their spectrum with CRs have to be clarified. The development of viable business models and value chains is just as important for the success of the TV white spaces usage as it is for other segments of wireless communications (Ballon and Delaere, 2009, Casey, 2009 and Nolan et al., 2007). What are possible business models to emerge? Moreover, an established value chain for the exploitation of TV white spaces is still missing. This is important to investors. An understanding of what factors will influence or favor certain models for making money is an important aspect for the successful usage of TV white spaces. This implies that either gradual growth or extension of existing wireless services value chains, for example towards mobile commerce or e-business value chains platforms, should be adopted. The latter approach seems to be more feasible by virtue of higher accessibility of services deployed through the Internet. Regulators are concerned about creating policies with incentives for using the white spaces while ensuring the protection of incumbent users of TV spectrum (ECC Report 159, 2011, FCC, 2010, Ghosh et al., 2011, Hwang and Yoon, 2009 and Peha, 2009). Questions that they have to answer include: What should be the operating parameters? How to build an accountability framework, that allows an interferer to be easily tracked down and disputes resolved either through legal or through other means? Further, how should cognitive devices be certified taking into account their ability to flexibly change operating parameters? It can be perceived that, these problems can be adequately resolved if different stakeholders in the value chain are involved or consulted. Otherwise, unilateral decisions by regulators on white space usage risks being counter-productive – either by being too restrictive rendering no technology operative, or by being too lax leading to increased harmful interference. Thus, clear identification of opportunities by involving other stakeholders can potentially balance the ecosystem and maximize economic value of the TV white spaces. As Hwang and Yoon (2008) pointed out, in addition to the research on the technology to exploit TV white spaces, it is important also to analyze the market or industry, or the proper interplay between technology, strategy and policy required to succeed in the commercialization of dynamic spectrum access (DSA) technology. Sensing technology is more appealing to academic researchers than other stakeholders (Weiss, Delaere, & Lehr, 2010); whereas regulators favor the geo-location database approach (FCC, 2010, OFCOM, 2010a and RSPG, 2011). This could be done in a commons or under spectrum trading. However, in case of scarcity, market based spectrum usage is said to be the best way to allocate spectrum resources (Cave et al., 2007, Coase, 1959, ECC Report 169, 2011 and Mastroeni and Naldi, 2010), such as through Broker based secondary spectrum trading (Bae et al., 2008 and Mwangoka et al., 2011). Therefore, a comparative analysis of the factors that might lead to one approach over another is important for optimal spectrum usage. To this end, this paper proposes a bicameral (two-chambered) geo-location database to accommodate viewpoints from diverse stakeholders, specifically the commons and secondary spectrum trading. Accordingly, four scenarios for spectrum acquisition are derived. To analyze the scenarios, this work proposes a theoretical assessment model that integrates the views from three categories of stakeholders: technology, business and regulatory. The assessment tries to answer the question whether access to TV white spaces should be free or paid, and how? The paper proceeds as follows. Section 2 introduces a bicameral geo-location database model and different approaches for accessing the TV white spaces. In addition, the section introduces a Broker based model for secondary spectrum trading of the TV white spaces. In Section 3, four scenarios are derived and a theoretical model to analyze them is presented. 4, 5 and 6 assess derived models from three perspectives: technological, business and regulatory, respectively. Finally, Section 7 summarizes and concludes the paper.

This work has attempted to analyze the technological, business and regulatory factors that will enable the exploitation of TV white spaces. A bicameral (two chambered) geo-location database, which supports both free and paid usage of TV white spaces under the commons and secondary spectrum trading regimes, respectively, was proposed. Four scenarios, namely; autonomous sensing, joint sensing and geo-location database, only geo-location database and Broker based secondary spectrum trading; were identified and analyzed by using an emerging technology evaluation methodology that integrates the perspectives of technology, business and regulatory stakeholders. Under the technology perceptive, the four scenarios were analyzed in terms of five performance indicators: cost saving, interference protection, spectrum mobility, quality of service and coexistence mechanism. Overall, the fourth scenario, i.e., Broker based secondary spectrum trading, seemed to have better prospects in terms of interference protection, spectrum mobility, quality of service and co-existence mechanism. These benefits have the potential to outweigh the significant cost incurred in terms of infrastructure development. The analysis of the four scenarios under the business models perspective considered value proposition, competitive advantage, and innovation incentives. The four scenarios depict differing potentials for building business models. However, the potential for developing value chains was seen as a key determinant for the success of a TV white spaces exploitation technology. Supported by outlooks from the regulatory and business model realms, scenarios based on the geo-location database appeared to have a better value proposition, competitive advantage, and innovation incentives. Under the regulatory policies perspective, the four scenarios were analyzed considering spectrum harmonization; spectrum usage rights (SURs) and certification. Automated regulatory management is regarded as a key enabler for the exploitation of TV white spaces through cognitive technologies, because of its capability to facilitate spectrum harmonization, definition of SURs and dynamic certification of reconfigurable radio devices/equipments. Thus, compared to autonomous sensing technology, geo-location based technologies seem to have the most optimal prospects. Whereas regulators are cautious to allow the usage of TV white spaces in general, this analysis shows that exploitation based on the proposed bicameral geo-location database that separates bands for free and paid usage should be adopted. Concurrently, the invocation of “safe bands” for the operation of unregistered PMSEs is inevitable to allow for better coordination of TV white spaces usage for the benefit of both incumbents and secondary spectrum users. This is further augmented by the potentials for developing viable value chains as shown in this study. Although, under scarcity, market based spectrum usage is preferred to commons usage, this analysis shows that they complement each other in the TV white spaces. Both can be used to deliver wireless services with different QoS provisioning strategies: best-effort services fit under the commons, while services requiring QoS guarantee fit under the secondary spectrum trading regime. Consequently, free and paid usage of TV white spaces will lead to the development of different business models, access technologies and regulatory policies. Finally, adoption of appropriate technical, business and regulatory approaches for the exploitation of TV white spaces will incentivize or motivate incumbent users of TV spectrum to allow other players in the bands. Examples of incentives to incumbents could include technologies that guarantee non-interfering operation to incumbents' services; business models that connect incumbents to the TV white spaces exploitation value chain; and regulatory policies that allow flexible spectrum usage such that even incumbents could use TV white space bands for other services as well. How incentive schemes for the exploitation of TV white spaces should work is an important topic for further study.