Channel calibration for a time division duplexed communication system
First Claim
1. A method for calibrating downlink and uplink channels in a wireless communication system, comprising:
- obtaining an estimate of a downlink channel response;
obtaining an estimate of an uplink channel response;
determining first and second sets of correction factors based on the estimates of the downlink and uplink channel responses; and
calibrating the downlink channel and uplink channel based on the first and second sets of correction factors and a scaling value to form a calibrated downlink channel and a calibrated uplink channel, wherein the scaling value is indicative of an average difference between the estimate of the downlink channel response and the estimate of the uplink channel response.
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Accused Products
Abstract
Techniques to calibrate downlink and uplink channels to account for differences in the frequency responses of transmit and receive chains are described. In one embodiment, pilots are transmitted on downlink and uplink channels and used to derive estimates of the downlink and uplink channel responses, respectively. Sets of correction factors are then determined based on estimates of downlink and uplink channel responses. A calibrated downlink channel is formed using a first set of correction factors for the downlink channel, and a calibrated uplink channel is formed using a second set of correction factors for the uplink channel. The first and second sets of correction factors may be determined using a matrix-ratio computation or a minimum mean square error computation. The calibration may be performed in real-time based on over-the-air transmission. Other aspects, embodiments, and features are also claimed and described.
454 Citations
34 Claims
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1. A method for calibrating downlink and uplink channels in a wireless communication system, comprising:
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obtaining an estimate of a downlink channel response; obtaining an estimate of an uplink channel response; determining first and second sets of correction factors based on the estimates of the downlink and uplink channel responses; and calibrating the downlink channel and uplink channel based on the first and second sets of correction factors and a scaling value to form a calibrated downlink channel and a calibrated uplink channel, wherein the scaling value is indicative of an average difference between the estimate of the downlink channel response and the estimate of the uplink channel response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus in a wireless communication system, comprising:
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means for obtaining an estimate of a downlink channel response; means for obtaining an estimate of an uplink channel response; means for determining first and second sets of correction factors based on the estimates of the downlink and uplink channel responses; and means for calibrating the downlink channel and uplink channel based on the first and second sets of correction factors and a scaling value to form a calibrated downlink channel and a calibrated uplink channel, wherein the scaling value is indicative of an average difference between the estimate of the downlink channel response and the estimate of the uplink channel response. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus in a wireless communication system, comprising:
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one or more processors configured to obtain an estimate of a downlink channel response, to obtain an estimate of an uplink channel response, to determine first and second sets of correction factors based on the estimates of the downlink and uplink channel responses, and to calibrate the downlink channel and uplink channel based on the first and second sets of correction factors and a scaling value to form a calibrated downlink channel and a calibrated uplink channel, wherein the scaling value is indicative of an average difference between the estimate of the downlink channel response and the estimate of the uplink channel response; and memory coupled to the one or more processors. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A non-transitory computer-readable storage medium encoded with instructions executable to:
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obtain an estimate of a downlink channel response; obtain an estimate of an uplink channel response; determine first and second sets of correction factors based on the estimates of the downlink and uplink channel responses; and calibrate the downlink channel and uplink channel based on the first and second sets of correction factors and a scaling value to form a calibrated downlink channel and a calibrated uplink channel, wherein the scaling value is indicative of an average difference between the estimate of the downlink channel response and the estimate of the uplink channel response.
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Specification