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US 7,257,377 B2Granted
Systems and methods for improving channel estimation
AssigneeQUALCOMM Incorporated
InventorsDurga Prasad Malladi, Josef Blanz, Yongbin Wei
Life of this patent
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Abstract
A method for improving channel estimation in a wireless communication system is disclosed. A wireless signal that includes a plurality of multipath components is received. N channel estimates are then obtained, where N is any positive integer greater than one. Each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components. The effects of interference between the plurality of multipath components on the N channel estimates is then reduced.
Claims19
A method for improving channel estimation in a wireless communication system, comprising:
- receiving a wireless signal that comprises a plurality of multipath components;
- obtaining N channel estimates, wherein N is any positive integer greater than one, wherein each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components, and wherein obtaining N channel estimates comprises:
- filtering the received wireless signal using a matched filter that is matched to an impulse response of a baseband filter;
- estimating N delays, wherein each of the N delays corresponds to a different multipath component of the plurality of multipath components;
- performing PN descrambling on the output of the matched filter N times, once after each of the N delays, thereby obtaining N descrambled signals;
- and
- correlating each of the N descrambled signals with a reference signal to obtain N channel estimates, wherein each of the N channel estimates corresponds to a different multipath component of the plurality of multipath components;
- calculating a multipath correlation matrix which comprises information about how signal components within N of the plurality of multipath components are correlated with one another;
- calculating a noise covariance matrix which comprises information about how noise components within N of the plurality of multipath components are correlated with one another, wherein the multipath correlation matrix and the noise covariance matrix are used to reduce the effects of interference between the plurality of multipath components on the N channel estimates;
- and
- reducing the effects of interference between the plurality of multipath components on the N channel estimates.
8 more elements
A mobile station for use in a wireless communication system, the mobile station comprising:
- at least one antenna for receiving a wireless signal that comprises a plurality of multipath components;
- a receiver in electronic communication with the at least one antenna;
- and
- an enhanced channel estimator that implements a method comprising:
- obtaining N channel estimates, wherein N is any positive integer greater than one, wherein each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components, and wherein obtaining N channel estimates comprises:
- filtering the received wireless signal using a matched filter that is matched to an impulse response of a baseband filter;
- estimating N delays, wherein each of the N delays corresponds to a different multipath component of the plurality of multipath components;
- performing PN descrambling on the output of the matched filter N times, once after each of the N delays, thereby obtaining N descrambled signals;
- and
- correlating each of the N descrambled signals with a reference signal to obtain N channel estimates, wherein each of the N channel estimates corresponds to a different multipath component of the plurality of multipath components;
- calculating a multipath correlation matrix which comprises information about how signal components within N of the plurality of multipath components are correlated with one another;
- calculating a noise covariance matrix which comprises information about how noise components within N of the plurality of multipath components are correlated with one another, wherein the multipath correlation matrix and the noise covariance matrix are used to reduce the effects of interference between the plurality of multipath components on the N channel estimates;
- and
- reducing the effects of interference between the plurality of multipath components on the N channel estimates.
11 more elements
An apparatus for use in a wireless communication system, the mobile station comprising:
- at least one antenna for receiving a wireless signal that comprises a plurality of multipath components;
- a receiver in electronic communication with the at least one antenna;
- and
- an enhanced channel estimator that implements a method comprising:
- obtaining N channel estimates, wherein N is any positive integer greater than one, wherein each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components, and wherein obtaining N channel estimates comprises:
- filtering the received wireless signal using a matched filter that is matched to an impulse response of a baseband filter;
- estimating N delays, wherein each of the N delays corresponds to a different multipath component of the plurality of multipath components;
- performing PN descrambling on the output of the matched filter N times, once after each of the N delays, thereby obtaining N descrambled signals;
- and
- correlating each of the N descrambled signals with a reference signal to obtain N channel estimates, wherein each of the N channel estimates corresponds to a different multipath component of the plurality of multipath components;
- calculating a multipath correlation matrix which comprises information about how signal components within N of the plurality of multipath components are correlated with one another;
- calculating a noise covariance matrix which comprises information about how noise components within N of the plurality of multipath components are correlated with one another, wherein the multipath correlation matrix and the noise covariance matrix are used to reduce the effects of interference between the plurality of multipath components on the N channel estimates;
- and
- reducing the effects of interference between the plurality of multipath components on the N channel estimates.
11 more elements
A mobile station for use in a wireless communication system, the mobile station comprising:
- means for receiving a wireless signal that comprises a plurality of multipath components;
- means for obtaining N channel estimates, wherein N is any positive integer greater than one, wherein each channel estimate of the N channel estimates corresponds to a different multipath component of the plurality of multipath components, and wherein means for obtaining N channel estimates comprises:
- means for filtering the received wireless signal using a matched filter that is matched to an impulse response of a baseband filter;
- means for estimating N delays, wherein each of the N delays corresponds to a different multipath component of the plurality of multipath components;
- means for performing PN descrambling on the output of the matched filter N times, once after each of the N delays, thereby obtaining N descrambled signals;
- and
- means for correlating each of the N descrambled signals with a reference signal to obtain N channel estimates, wherein each of the N channel estimates corresponds to a different multipath component of the plurality of multipath components;
- means for calculating a multipath correlation matrix which comprises information about how signal components within N of the plurality of multipath components are correlated with one another
- means for calculating a noise covariance matrix which comprises information about how noise components within N of the plurality of multipath components are correlated with one another, wherein the multipath correlation matrix and the noise covariance matrix are used to reduce the effects of interference between the plurality of multipath components on the N channel estimates;
- and
- means for reducing the effects of interference between the plurality of multipath components on the N channel estimates.
8 more elements
Dependencies are inferred from the claim text.