Local positioning services on IEEE 802.11 networks

This paper deals with localization services in IEEE 802.11 networks. The proposed solution processes the Time Of Arrival (TOA) of location packets sent by any Mobile Terminal, received by the Location Supporting Nodes (LSN) and the Location Support Server (LSS) that compose the location services architecture. A fully compatible IEEE 802.11 Localization Services protocol supporting data exchange related to both TOA measurement and processing is reported. - Simulation results show the method efficiency in both IEEE 802.11 PCF and DCF modes. Assessment of the maximum number of MTs for which location services can be provided is also reported. Since high localization accuracy requires large bandwidth, a broadband antenna for LSN and LSS was designed. The related results are reported in the second part of the paper. Antenna was tested by HP 8510 Network analyzer for the s-parameters, and by anechoic chamber for the radiation pattern and polarization purity. The antenna works at 5.0 GHz (centre frequency) in broadband mode and is matched on the wireless operating frequencies with a percentage more than 8% (1:1.5 VSWR).

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