Channel quality index feedback reduction for broadband systems
AssigneeApple Inc.
InventorJayesh H. Kotecha
Life of this patent
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Abstract
Systems and methodology for exploiting channel correlation in time and/or frequency to reduce CQI feedback in wireless communications systems. By compressing CQI feedback at the receiver to reduce redundancy in CQI feedback information that results from the channel correlation, the average feedback rate is reduced. In various embodiments, redundancy in time may be removed from the CQI feedback by monitoring variations of the CQI information in time at the receiver so that CQI information for a given CQI reporting instance is communicated to the transmitter only if it differs from the CQI information for the previous CQI reporting instance. Otherwise, no feedback is performed. In other embodiments, CQI feedback is compressed by performing a discrete cosine transform (DCT) on the CQI data.
Claims32
A method for processing signals in a wireless communication system comprising a plurality of transmission channels, the method comprising:
- detecting at least one change in channel state information for a plurality of reporting instances;
- and
- ranking the detected at least one change in channel state information;
- and
- generating a compressed set of channel quality indicator (CQI) information, the compressed set configured to omit at least one CQI information based on the ranking;
- wherein:
- each of the plurality of transmission channels comprises one or more CQI parameters;
- and
- the compressed set of CQI information comprises information useful for transmitting data from a transmitting device to a receiving device over one or more of the plurality of transmission channels.
A receiver for use in a wireless communication system, comprising:
- a channel state change detector configured to detect changes in channel state information in a plurality of reporting instances, the channel state change detector comprising:
- a discrete cosine transform (DCT) apparatus configured to calculate DCT coefficients;
- and
- a processor configured to detect changes in calculated DCT coefficients;
- a channel quality indicator (CQI) compression apparatus configured to generate a compressed set of CQI information, the compressed set of CQI information configured to remove redundant CQI information;
- and
- a transmitter configured to transmit the compressed set of CQI information over a channel.
A transmitter for use in a wireless communication system, comprising:
- first apparatus configured to receive a compressed set of transmission channel state information;
- and
- second apparatus configured to use the compressed set of transmission channel state information to generate signal processing information to transmit data from the transmitter to a receiver over a transmission channel;
- wherein:
- the compressed set of transmission channel state information comprises information generated at the receiver, and information derived from detected changes in transmission channel state information;
- and
- the compressed set of transmission channel state information comprises only transmission channel state information that meets predetermined selection metrics, the predetermined selection metrics being configured to remove at least one channel quality indicator.
A method for processing signals in a wireless communication system comprising a plurality of transmission channels, the method comprising:
- detecting at least one change in channel state information for a plurality of reporting instances;
- ranking the detected at least one change in channel state information;
- generating a compressed set of channel quality indicator (CQI) information, the compressed set configured to omit redundant CQI information, wherein:
- each of the plurality of transmission channels comprises one or more CQI parameters;
- the compressed set of CQI information comprises information useful for transmitting data from a transmitting device to a receiving device over one or more of the plurality of transmission channels;
- and
- transmitting the compressed set of CQI information to the transmitting device using an index corresponding to CQI information entries in one or more predefined codebooks.
A transmitter for use in a wireless communication system, comprising:
- first apparatus configured to receive a compressed set of transmission channel state information;
- and
- second apparatus configured to use the compressed set of transmission channel state information to generate signal processing information to transmit data from the transmitter to a receiver over a transmission channel;
- where:
- the compressed set of transmission channel state information comprises information generated at the receiver, and information derived from detected changes in transmission channel state information;
- and
- the compressed set of transmission channel state information comprises only transmission channel state information that meets predetermined selection metrics, the predetermined selection metrics being configured to remove redundant data;
- and
- wherein the compressed set of transmission channel state information is transmitted from the receiver to the transmitter using an index corresponding to channel quality indicator (CQI) information entries in codebooks in the receiver and the transmitter.
A method for processing signals in a wireless communication system comprising a plurality of transmission channels each comprising on or more channel quality indicator (CQI) parameters, the method comprising:
- detecting at least one change in channel state information for a plurality of reporting instances;
- ranking the detected at least one change in channel state information;
- and
- generating a compressed set of channel quality indicator (CQI) information, the compressed set configured to omit redundant CQI information, the compressed set of CQI information comprising information useful for transmitting data from a transmitting device to a receiving device over one or more of the plurality of transmission channels;
- wherein the compressed set of CQI information comprises only CQI information that meets one or more predetermined selection metrics that are dynamically changed between a first CQI reporting instance and a second CQI reporting instance;
- and
- wherein the generating of the compressed set of CQI information comprises:
- ranking CQI values for a first plurality of candidate clusters having a changed CQI information;
- selecting therefrom a subset of clusters, the selecting comprising identifying the candidate clusters having the largest change in CQI magnitude;
- and
- using the changed CQI information of the subset of clusters to generate the compressed set of CQI information.
Dependencies are inferred from the claim text.