METHOD AND APPARATUS FOR TIME-ALIGNING TRANSMISSIONS FROM MULTIPLE BASE STATIONS IN A CDMA COMMUNICATION SYSTEM
First Claim
1. A method in a wireless communication system, comprising:
- obtaining a time difference value for at least a first base station selected from a plurality of base stations in said wireless communication system, the time difference value being a difference between a timing of the first base station and a timing of a reference base station in said wireless communication system;
estimating an actual timing of the first base station based on the time difference value obtained for the first base station and the timing of the reference base station; and
initiating a search for the first base station by a terminal communicating within the wireless communication system based on the estimated actual timing for the first base station.
1 Assignment
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Accused Products
Abstract
Schemes to time-align transmissions from multiple base stations to a terminal. To achieve time-alignment, differences between the arrival times of transmissions from the base stations, as observed at the terminal, are determined and provided to the system and used to adjust the timing at the base stations such that terminal-specific radio frames arrive at the terminal within a particular time window. In one scheme, a time difference between two base stations is partitioned into a frame-level time difference and a chip-level time difference. Whenever requested to perform and report time difference measurements, the terminal measures the chip-level timing for each candidate base station relative to a reference base station. Additionally, the terminal also measures the frame-level timing and includes this information in the time difference measurement only if required. Otherwise, the terminal sets the frame-level part to a predetermined value (e.g., zero).
35 Citations
4 Claims
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1. A method in a wireless communication system, comprising:
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obtaining a time difference value for at least a first base station selected from a plurality of base stations in said wireless communication system, the time difference value being a difference between a timing of the first base station and a timing of a reference base station in said wireless communication system;
estimating an actual timing of the first base station based on the time difference value obtained for the first base station and the timing of the reference base station; and
initiating a search for the first base station by a terminal communicating within the wireless communication system based on the estimated actual timing for the first base station.
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2. An apparatus in a wireless communication system, comprising:
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means for obtaining a time difference value for at least a first base station selected from a plurality of base stations in said wireless communication system, the time difference value for the first base station being a difference between a timing of the first base station and a timing of a reference base station within said wireless communication system;
means for estimating an actual timing of the first base station based on the time difference value obtained for the first base station and the timing of the reference base station; and
means for initiating a search for the first base station by a terminal communicating within the wireless communication system based on the estimated actual timing for the first base station.
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3. A terminal in a wireless communication system, comprising:
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a data processor for obtaining a time difference value for at least a first base station in the wireless communication system, wherein the time difference value for the first base station is a difference between a timing of the first base station and a timing of a reference base station within the wireless communication system; and
a controller for estimating an actual timing of the first base station based on the time difference value obtained for the first base station and the timing of the reference base station, and to initiate a search for the first base station based on the estimated actual timing for the first base station.
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4. A computer program product including a computer-readable medium physically embodied with computer-readable program code for:
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obtaining a time difference value for at least a first base station selected from a plurality of base stations in a wireless communication system, the time difference value being a difference between a timing of the first base station and a timing of a reference base station in said wireless communication system;
estimating an actual timing of the first base station based on the time difference value obtained for the first base station and the timing of the reference base station; and
initiating a search for the first base station by a terminal communicating within the wireless communication system based on the estimated actual timing for the first base station.
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Specification