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- Experimental assessment of a propagation model for TV white spacesPublication . Dionísio, Rogério Pais; Marques, Paulo; Rodriguez, JonathanThis paper describes outdoor field measurements in television white spaces (TVWS) carried out in Munich, Germany. Fixed and mobile measurements in rural, sub-urban and urban scenarios showed that the modified Hata model is appropriate to describe the path loss over distances up to few kilometers, and may be used in the process to populate a geo-location database.
- TV white spaces maps computation through interference analysisPublication . Dionísio, Rogério Pais; Marques, Paulo; Rodriguez, JonathanFor the characterization of TV White Spaces (TVWS), an extensive simulation of the impact of interfering signals was undertaken in a generalized scenario. The simulation for these investigations was derived from a Monte Carlo methodology using SEAMCAT, and the results include the computation of TVWS maps as it can be done with the access to a geo-location database, or based on autonomous sensing only. Geo-location database approach is shown to utilize TVWS spectrum more efficiently. The impact of Professional Wireless Microphone Systems (PWMS) devices on the availability of TVWS is also analyzed and imposes additional limitations of the maximum power emitted by secondary spectrum users.
- Combination of a geolocation database access with infrastructure sensing in TV bandsPublication . Dionísio, Rogério; Ribeiro, Jorge Miguel Afonso; Marques, Paulo; Rodriguez, JonathanThis paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial wireless microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate wireless microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered wireless microphones.