Recent FCC regulations on TV white spaces allow geo-location databases to be the sole source of spectrum information for White Space Devices (WSDs). Geo-location databases protect TV band incumbents by keeping track of TV transmitters and their protected service areas based on their location, transmission parameters and sophisticated propagation models. In this article, we argue that keeping track of both TV transmitters and TV receivers (i.e. TV sets) can achieve significant improvement in the availability of white spaces. We first identify wasted spectrum opportunities, both temporal and spatial, due to the current approach of white spaces detection. We then propose DynaWhite, a cloud-based architecture that orchestrates the detection and dissemination of highly-dynamic, real-time, and fine-grained TV white space information. DynaWhite introduces the next generation of geo-location databases by combining traditional sensing techniques with a novel unconventional sensing approach based on the detection of the passive TV receivers using standard cell phones. We present a quantitative evaluation of the potential gains in white space availability for large scale deployments of DynaWhite. We finally identify challenges that need to be addressed in the research community in order to exploit this potential for leveraging dynamic real-time fine-grained TV white spaces.
There are currently two approaches to ensuring the protection of TV white space incumbents both based on TV transmitters information. The first approach, adopted by the FCC, relies on geo-location databases that keep track of TV transmitters' parameters and propagation models in order to estimate the areas that need to be protected @cite_5 . The work presented in @cite_7 extends this approach through using sophisticated propagation models and presents a scalable architecture of geo-location databases. The second approach, adopted by the IEEE 802.22 standard, relies on collaborative spectrum sensing between the WSDs. In this approach, WSDs submit their spectrum view to a central entity that is responsible for performing spectrum sharing functionalities @cite_0 . incorporates these two approaches and extends them by its unconventional sensing approach for TV receivers.
@cite_0 @cite_5 @cite_7
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The most recent FCC ruling proposes relying on a database of incumbents as the primary means of determining white space availability at any white spaces device (WSD). While the ruling provides broad guidelines for the database, the specifics of its design, features, implementation, and use are yet to be determined. Furthermore, architecting a network where all WSDs rely on the database raises several systems and networking challenges that have remained unexplored. Also, the ruling treats the database only as a storehouse for incumbents. We believe that the mandated use of the database has an additional opportunity: a means to dynamically manage the RF spectrum. Motivated by this opportunity, in this paper we present SenseLess, a database driven white spaces network. As suggested by its very name, in SenseLess, WSDs obviate the need to sense the spectrum by relying entirely on a database service to determine white spaces availability. The service, using a combination of an up-to-date database of incumbents, sophisticated signal propagation modeling, and an efficient content dissemination mechanism ensures efficient, scalable, and safe white space network operation. We build, deploy, and evaluate SenseLess and compare our results to ground truth spectrum measurements. We present the unique system design considerations that arise due to operating over the white spaces. We also evaluate its efficiency and scalability. To the best of our knowledge, this is the first paper that identifies and examines the systems and networking challenges that arise from operating a white space network, which is solely dependent on a channel occupancy database. Geo-location database driven white space network is a very promising approach for improving secondary spectrum utilization. In this paper, we consider the business modeling for geo-location database driven white space network. In our proposed model, the database acts as a spectrum broker buying (reserving) bandwidth from spectrum licensees in advance, and then resells the reserved bandwidth to unlicensed white space devices (WSDs) in real-time. We study the optimal bandwidth reservation for the database with WSDs' demand uncertainty under both information symmetry and asymmetry. Under information symmetry, the database and the WSD experience the same degree of uncertainty about the market demand. We derive the optimal bandwidth reservations in a centralized integrated manner (as a benchmark). Under information asymmetry, the WSD has more information (i.e., with less uncertainty) about demand (due to the proximity to end-users). We propose a contract-based bandwidth reservation mechanism, which ensures WSDs share their local information with the database credibly. We further characterize the optimal bandwidth reservation contract systematically. Simulations show that under information asymmetry, the optimal bandwidth reservation contract improves both the database's profit and the social welfare significantly (larger than 30 in our simulations) without sacrificing the WSDs' benefits, comparing to those mechanisms without information sharing. According to the recent rulings of the Federal Communications Commission (FCC), TV white spaces (TVWS) can now be accessed by secondary users (SUs) after a list of vacant TV channels is obtained via a geo-location database. Proper business models are essential for database operators to manage the cost of maintaining geo-location databases. Database access can be simultaneously priced under two different schemes: the registration scheme and the service plan scheme. In the registration scheme, the database reserves part of the TV bandwidth for registered White Space Devices (WSD) in a soft-license way. In the service plan scheme, WSDs are charged according to their queries. In this paper, we investigate the business model for the TVWS database under a hybrid pricing scheme. We consider the scenario where a database operator employs both the registration scheme and the service plan scheme to serve the SUs. The SUs' choices of different pricing schemes are modeled as a non-cooperative game and we derive distributed algorithms to achieve the Nash Equilibrium (NE). Considering the NE of the SUs, the database operator optimally determines the pricing parameters for both pricing schemes in terms of bandwidth reservation, registration fee and query plans. The opening of the television bands in the United States presents an exciting opportunity for secondary spectrum utilization. Protecting licensed broadcast television viewers from harmful interference due to secondary spectrum usage is critical to the successful deployment of TV white space devices. A wide variety of secondary system operating scenarios must be considered in any potential interference analysis, as described below. Several different types of licensed television transmitters currently exist in the TV bands, along with secondary licensed services, such as wireless microphones. All licensed services must be adequately protected from harmful interference, which can readily and reliably be achieved with the described geo-location database methods. Specific implementation details of geo-location databases are discussed, including several complexity reduction techniques. Geo-location database techniques are also shown to more efficiently utilize available spectrum than other spectrum access techniques.