Cognitive indoor positioning in TV white spaces

Recent evolution in regulation of access to TV channels allocated in UHF frequencies (DVB-T) makes vacant channels (TV White Spaces - TVWS) available to wireless data services. While this opportunity is currently widely studied by the cognitive radio community for communications, the use of TVWS for indoor positioning is all but unexplored. Frequencies below 900 MHz are extremely appealing for positioning due to a more uniform signal propagation with respect to the ISM bands and a lower attenuation when passing through obstacles. This work focuses indeed on indoor positioning in the TVWS. A TVWS positioning system is proposed and compared against WiFi-based solutions, in terms of energy efficiency, operating range, and impact of network topology. Moreover, the formulation of a cognitive paradigm for optimal selection of the topology of Access Points and of network topology in a TVWS communication and positioning system is given. The proposed algorithm takes into account constraints related to positioning accuracy and communication performance. Results obtained analytically and by simulation show that favorable propagation conditions characterizing the TVWS frequencies, in conjunction with an optimized system organization and topology, lead to highly accurate positioning and improved energy efficiency over traditional schemes, thanks to lower transmit power levels. The proposed solution is therefore also appealing in light of recent trends towards green wireless communications. © 2013 IEEE.