Patent ID: 6208871
Filing Date: 2001-03-27
Classification: H04J,H04W

Abstract:
In a wireless communication system, comprising at least a first and a second base transceiver station, a method for providing a time adjustment to the second base transceiver station, the method comprising the steps of:receiving an identity of the first and second base transceiver station at a mobile station, wherein the step of receiving the identity comprises the step of receiving a first base station identity number and a first PN short code time offset of the first base station transceiver, and a second base station identity number and a second PN short code time offset of the second base station transceiver, wherein the second base station transceiver adjusts a timing such that the second base station transceiver is synchronized in time to the first base station transceiver;tracking a first signal from the first base transceiver station and a second signal from the second base transceiver station by the mobile station, based on the identity, to yield a first and second time offset wherein the step of tracking the first signal by the mobile station comprises the steps of:acquiring a pilot channel of the first signal from the first base station transceiver via correlation to a PN short code by the mobile station;decoding a sync channel of the first signal to verify the first PN short code time offset and the first base station identity number via coherent demodulation provided by the pilot signal;decoding a paging channel of the first signal to acquire a neighbor list comprised of PN short code time offsets associated with neighboring base station transceivers, including at least the second base station transceiver;enabling a phase lock loop algorithm in the mobile station to begin adjusting a local oscillator frequency of the mobile station to synchronize to an oscillator frequency of the first base station transceiver;initiating a timer in the mobile station upon enabling the phase lock loop algorithm;freezing the phase lock loop algorithm upon expiration of the timer, thereby yielding a stable free running local oscillator frequency in the mobile station which is substantially equal to the oscillator frequency of the first base transceiver station;extracting a first time offset from the first signal by a mobile station controller; andterminating tracking of the first signal by the mobile station;determining a timing adjustment calculation based on the first time offset of the first signal and the second time offset of the second signal by the mobile station; andtransmitting the timing adjustment calculation to the second base station transceiver.