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- Evaluation of blind sensing techniques in multiple wireless microphones environmentsPublication . Dionísio, Rogério Pais; Marques, Paulo; Ribeiro, José CarlosThis work focuses on the evaluation of blind sensing techniques for the detection of multiple wireless microphones in the UHF band, by means of simulation. The metrics used for the comparisons include probability of detection, probability of false alarm and minimum SNR detected for a given observation time. As an example, simulation results showed that blind detection algorithms can sense multiple wireless microphone signals with SNR = -19 dB, in a Rayleigh channel environment, considering 100 ms sensing time, 90 % probability of detection and 10 % probability of false alarm. In these conditions, blind detection techniques suffer maximum SNR degradation of 3.5 dB, as compared with single wireless microphone scenarios.
- Some initial results and observations from a series of trials within the Ofcom TV white spaces pilotPublication . Holland, Oliver; Ping, Shuyu; Sastry, Nishanth; Chawdhry, Pravir; Chareau, Jean-Marc; Bishop, James; Xing, Hong; Taskafa, Suleyman; Aijaz, Adnan; Bavaro, Michele; Viaud, Philippe; Pinato, Tiziano; Anguili, Emanuele; Akhavan, Mohammad Reza; McCann, Julie; Gao, Yue; Qin, Zhijin; Zhang, Qianyun; Knopp, Raymond; Kaltenberger, Florian; Nussbaum, Dominique; Dionísio, Rogério Pais; Ribeiro, José Carlos; Marques, Paulo; Hallio, Juhani; Jakobsson, Mikko; Auranen, Jani; Ekman, Reijo; Kokkinen, Heikki; Paavola, Jarkko; Kivinen, Arto; Solc, Tomaz; Mohorcic, Mihael; Tran, Ha-Nguyen; Ishizu, Kentaro; Matsumura, Takeshi; Ibuka, Kazuo; Harada, Hiroshi; Mizutani, KeiichiTV White Spaces (TVWS) technology allows wireless devices to opportunistically use locally-available TV channels enabled by a geolocation database. The UK regulator Ofcom has initiated a pilot of TVWS technology in the UK. This paper concerns a large-scale series of trials under that pilot. The purposes are to test aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white space devices, among others. An additional key purpose is to perform research investigations such as on aggregation of TVWS resources with conventional resources and also aggregation solely within TVWS, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper provides an update on the trials, giving an overview of their objectives and characteristics, some aspects that have been covered, and some early results and observations.
- Cross-platform demonstrator combining spectrum sensing and a geo-location databasePublication . Dionísio, Rogério Pais; Ribeiro, José Carlos; Ribeiro, Jorge Miguel Afonso; Marques, Paulo; Rodriguez, JonathanAfter the digital switchover, a secondary access of the so-called TV White Spaces should not interfere with primary users, such as DVB-T systems and local wireless microphone devices. One consensual method for secondary spectrum users to avoid interference is to combine geo-location database with spectrum sensing. This paper describes an experimental platform that combines wireless microphone sensors with a web-based geo-location database access. Software defined radios and Internet technologies are the enabling tools in use. From test trials in a real scenario, the platform was capable to update a list of vacant channel from the geo-location database, using reliable information from blind sensing algorithms.
- TV white spaces with geo-location database access: practical considerations and trials in EuropePublication . Dionísio, Rogério Pais; Ribeiro, José Carlos; Ribeiro, Jorge Miguel Afonso; Marques, Paulo; Rodriguez, JonathanThis chapter describes outdoor transmission tests and field measurements in TV white spaces (TVWS) carried out in Europe. TVWS Measurements in Germany showed that the extended Hata model is appropriate to describe the path loss over distances up to a few kilometers. During the TVWS trial in Slovenia, we combine infrastructure sensing with geo-location database access to protect not only DVB-T, but also wireless microphone (WM) signals from TVWS devices interference.