Method and apparatus for transmitting data in a time division duplexed (TDD) communication system
First Claim
1. A method for performing data processing in a wireless communication system, the method comprising:
- calibrating at least one communication link between a base station and a terminal;
obtaining a channel response estimate for the at least one communication link based on one or more pilots; and
deriving at least one eigenvector from the channel response estimate usable for spatial processing of the at least one communication link, wherein deriving comprises decomposing a matrix corresponding to the channel response estimate.
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Accused Products
Abstract
Techniques to process data for transmission in a time division duplexed (TDD) communication system. In one aspect, the frequency response of a forward link is estimated at a base station based on reverse link transmissions (e.g., pilots) from a terminal. Prior to a data transmission on the forward link, the base station determines a reverse transfer function based on the pilots transmitted by the terminal, “calibrates” the reverse transfer function with a calibration function to derive an estimate of a forward transfer function, and preconditions modulation symbols based on weights derived from the forward transfer function. In another aspect, the terminal estimates the “quality” of the forward link and provides this information to the base station. The base station then uses the information to properly code and modulate data prior to transmission such that the transmitted data can be received by the terminal at the desired level of performance.
34 Citations
35 Claims
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1. A method for performing data processing in a wireless communication system, the method comprising:
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calibrating at least one communication link between a base station and a terminal; obtaining a channel response estimate for the at least one communication link based on one or more pilots; and deriving at least one eigenvector from the channel response estimate usable for spatial processing of the at least one communication link, wherein deriving comprises decomposing a matrix corresponding to the channel response estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for performing data processing in a wireless communication system comprising:
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means for calibrating at least one communication link between a base station and a terminal; means for obtaining a channel response estimate for the at least one communication link based on one or more pilots; and means for decomposing the channel response estimate to obtain one or more eigenvectors usable for spatial processing of the one or more communication links, wherein the means for calibrating comprises; means for determining a reverse link calibration function; and means for applying the forward link calibration function and a reverse link calibration function. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A wireless communication unit in a time division duplexed (TDD) communication system, comprising:
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a processor configured to estimate characteristics of a communication link based on a received first transmission, to derive a calibration function indicative of a difference between the first transmission and a second transmission, and to precondition modulation symbols based on weights derived at least in part from the estimated characteristics and on the calibration function; and a plurality of antennas coupled with the processor. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A method for performing data processing in a wireless communication system, the method comprising:
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calibrating at least one communication link between a base station and a terminal; obtaining a channel response estimate for the at least one communication link based on one or more pilots; and deriving at least one eigenvector from the channel response estimate usable for spatial processing of the at least one communication link, wherein performing spatial processing comprises transmitting a pilot on a second link, in a direction opposite the first link, using the one or more eigenvectors. - View Dependent Claims (24, 25, 26, 27)
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28. A method for performing data processing in a wireless communication system, the method comprising:
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calibrating at least one communication link between a base station and a terminal; obtaining a channel response estimate for the at least one communication link based on one or more pilots; deriving at least one eigenvector from the channel response estimate usable for spatial processing of the at least one communication link, wherein calibrating comprises calibrating based upon a calibration function; and determining the calibration function based upon a forward link calibration function and a reverse link calibration function. - View Dependent Claims (29, 30)
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31. A method for performing data processing in a wireless communication system, the method comprising:
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calibrating at least one communication link between a base station and a terminal; obtaining a channel response estimate for the at least one communication link based on one or more pilots; and deriving at least one eigenvector from the channel response estimate usable for spatial processing of the at least one communication link, wherein the wireless communication system implements orthogonal frequency division modulation (OFDM), and wherein the at least one communication link comprises a plurality of frequency subchannels. - View Dependent Claims (32)
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33. An apparatus for performing data processing in a wireless communication system comprising:
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means for calibrating at least one communication link between a base station and a terminal; means for obtaining a channel response estimate for the at least one communication link based on one or more pilots; and means for decomposing the channel response estimate to obtain one or more eigenvectors usable for spatial processing of the one or more communication links, wherein the means for calibrating comprises means for determining the calibration function based upon a forward link calibration function and a reverse link calibration function. - View Dependent Claims (34, 35)
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Specification