Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Patent
1997-07-22
2000-02-01
Urban, Edward F.
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
455 676, 342457, H04Q 720
Patent
active
060213302
ABSTRACT:
Methods and apparatus for estimating mobile location in a wireless communication system including a plurality of base stations. In a base-to-mobile embodiment, the system base stations periodically transmit location signals to mobile stations during a system-wide blank-and-burst interval during which normal wireless communications are suspended. The interval is made sufficiently short that disruption to normal operation is negligible. Each base station transmits a distinct location signal which can be identified by a mobile station as associated with a particular base station. A given mobile station for which a location estimate is to be generated detects location signals from at least three of the system base stations. The detected location signals are used to generate differential path delay measurements which may be further processed in accordance with a triangulation technique to generate an estimate of mobile location. The suspension of normal wireless communications permits the location signals to occupy a broad bandwidth corresponding to multiple voice data channels, such that high resolution differential path delay measurements can be generated. The location signals from adjacent or neighboring base stations may also be configured to appear mutually orthogonal at a receiving mobile station, such that location signals from base stations close to a mobile will not interfere with detection of a location signal from a more distant base station. For example, the location signals may be selected to have waveforms which exhibit substantially non-overlapping comb-like frequency spectra. The invention may also be implemented in partial system blanking embodiments and mobile-to-base embodiments.
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Gesesse Tilahun
Lucent Technologies - Inc.
Urban Edward F.
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