Lucent Technologies Inc.

Agere Systems Inc.

Jonathan Michael Tobias

Alex Matusevich

Sheng-Jen Tsai

Chris Constantine Tsamutalis

Mohsen Sarraf

Robert Chuenlin Wang

Thomas W Goeddel

Brian J Bogdan

Winston Edward Pekrul

Alexander Gordon

Russell Bernard Benedict

Michael J Golden

In the method for dynamically determining interference and carrier-to-interference ratio, interference is measured during an active TDMA time slot. In one embodiment, a base station determines the interference level in an active time slot using power level measurement taken during a DTX OFF period, when a mobile station is transmitting in discontinuous transmission mode. In another embodiment, a base station orders a mobile station to cease transmission during a SACCH portion of the time slot, and determines an interference level I measurement using power level measurements taken during the inactive SACCH field. Another embodiment provides for the determination of an interference level I using power level measurements taken during the guard and ramp fields.

Method to dynamically determine interference and carrier-to-interference ration during TDMA calls

A phase-modulated signal such as a quadrature phase-shift-keyed (QPSK) signal in a wireless communication system is demodulated using sample timing based at least in part on frequency information generated by frequency demodulating the phase-modulated signal. The phase-modulated signal is separated into first and second portions, the first portion is phase demodulated to generate demodulated symbols, and the second portion is frequency demodulated to generate, e.g., a measure of the instantaneous frequency of the phase-modulated signal. The instantaneous frequency measure is processed to identify one or more symbol transitions, and the identified transitions are used to establish the sample timing such that proper sampling of the symbols is ensured.

Sample timing control for demodulation of phase-modulated signals

A phase-modulated signal such as a quadrature phase-shift-keyed (QPSK) signal in a wireless communication system is demodulated by frequency demodulating the phase-modulated signal. The phase-modulated signal is separated into first and second copies, the first copy is phase demodulated to generate demodulated symbols, and the second copy is frequency demodulated to generate, e.g., a measure of the instantaneous frequency of the phase-modulated signal. The instantaneous frequency measure is processed to identify one or more symbol transitions, and the identified transitions are used to generate event signals having signature properties (signature events). These signature events are used in traditional Time Difference of Arrival tdoa algorithms to accurately determine position of a mobile unit in the wireless communication system.

Apparatus and method for finding location of a mobile unit

A method for locating a mobile unit without synchronizing base-stations is provided. A triangulation scheme where distances between a plurality of base-stations and a mobile unit (herein termed mobile) are calculated by measuring at least three round-trip-delay-values wherein each round-trip-delay-value corresponds to transmission of a downlink signal from each base-station to the mobile unit and transmission of an uplink signal, in response to the downlink signal, from the mobile unit to each base-station is described. It is a low-cost solution without requiring the participating base-stations to be accurately synchronized in time and with the added advantages of utilizing a known downlink signal and a known uplink signal in determining the position of the mobile.

Locating a mobile unit in a wireless time division multiple access system

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Florham Park, NJ, United States of America

Jonathan Michael Tobias