Base station synchronization
First Claim
1. A method, implemented in a radio network controller (RNC), for maintaining synchronization of base stations, the method comprising:
- updating a covariant matrix and a database;
detecting that a time error variance of a first base station exceeds a predetermined threshold;
transmitting a signal to instruct a user equipment (UE) to measure a time difference of arrival (TDOA) between signals transmitted from the first base station and a reference base station;
receiving the TDOA measurement;
comparing the TDOA measurement with a value stored in the database; and
transmitting a message to the first base station to adjust its transmission timing based on said comparison.
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Abstract
In a radio network controller (RNC), a covariant matrix and a database are updated. The RNC then detects that a first base station'"'"'s time-error-variance exceeds a predetermined threshold. In response, the RNC signals to a user-equipment (UE) to measure a time difference of arrival (TDOA) between signals transmitted from the first base station and a reference base station. The UE measures the requested TDOA between the designated base stations and reports the measurement results back to the RNC. The RNC then compares the measured TDOA with a TDOA value stored in the database. Based on the comparison, the RNC signals to the first base station to adjust its time base.
41 Citations
11 Claims
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1. A method, implemented in a radio network controller (RNC), for maintaining synchronization of base stations, the method comprising:
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updating a covariant matrix and a database; detecting that a time error variance of a first base station exceeds a predetermined threshold; transmitting a signal to instruct a user equipment (UE) to measure a time difference of arrival (TDOA) between signals transmitted from the first base station and a reference base station; receiving the TDOA measurement; comparing the TDOA measurement with a value stored in the database; and transmitting a message to the first base station to adjust its transmission timing based on said comparison. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An RNC configured to maintain base stations synchronized, wherein said base stations are within a node B, the RNC comprising:
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a covariant matrix configured to maintain a state estimate of each of a plurality of base stations, and wherein said state estimates include a time error of each base station relative to a reference, a rate of change of each time error, and a transmission delay between base station pairs; a database configured to maintain received TDOA measurement values between signals transmitted from a first base station and a reference base station; a message generator configured to generate and transmit measurement-request messages; a measurement receive device configured to receive and process received TDOA measurement values; and a synchronization controller configured to compute a time of transmission of each of the base stations and filter gains based on received TDOA measurement values. - View Dependent Claims (8, 9, 10, 11)
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Specification