Feedback scheduling to reduce feedback rates in MIMO systems
AssigneeApple Inc.
InventorsJayesh H. Kotecha, Kaibin Huang
Life of this patent
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Abstract
In a closed-loop wireless communication system, a codebook-based feedback control mechanism is provided where feedback from each of a plurality of receivers is scheduled to control the feedback so that the receiving devices do not needlessly feed back precoding information to the transmitting device. The feedback may be controlled by establishing and distributing a schedule to control when each receiver feeds back precoding information, or by establishing and distributing a metric-based feedback threshold that must be satisfied before feedback is permitted.
Claims25
A method for controlling feedback of precoding information in a MIMO communication system comprising a transmitting device and a plurality of receiving devices, wherein the transmitting device communicates with each receiving device over a respective transmission channel, the method comprising:
- generating feedback control information at the transmitting device for each receiving device;
- broadcasting the feedback control information to the plurality of receiving devices;
- receiving one or more feedback at the transmitting device from one or more of the plurality of receiving devices, where each receiving device evaluates the feedback control information to determine a feedback constraint, where the feedback constraint is a threshold value used to determine when a receiving device of the plurality of receiving devices provides feedback to the transmitting device, wherein each receiving device evaluation includes tracking a scheduling history for each of the plurality of receiving devices;
- wherein the one or more feedback comprises precoding information;
- and
- wherein the feedback control information is configured to reduce the frequency of the one or more feedback to the transmitting device.
A base station for use in a wireless LTE communication system, comprising:
- scheduling logic operable to define one or more scheduling criteria for scheduling feedback of precoding information at each of a plurality of user devices so that each user device evaluates the one or more scheduling criteria to determine if precoding information is to be fed back by said user device and to determine which one or more feedback factors of a plurality of feedback factors to send, wherein each user device evaluation includes tracking a scheduling history for each of the plurality of user devices;
- where the plurality of feedback factors comprises at least a precoding parameter, a power allocation parameter, and an adaptive modulation and coding parameter;
- and
- transmission logic operable to transmit the one or more scheduling criteria to the plurality of user devices using a downlink channel.
A method for controlling feedback in a MIMO communication system comprising a base station and a plurality of user equipment devices, wherein the base station communicates with each of the plurality of user equipment devices over a respective transmission channel, the method comprising:
- receiving feedback control information at each of the plurality of user equipment devices from a base station, the feedback control information configured to initialize at least a set of evaluative criteria;
- evaluating the feedback control information at each of the plurality of user equipment devices, wherein evaluating the feedback control information comprises tracking a scheduling history for each of the plurality of user equipment devices;
- and
- transmitting feedback meeting the set of evaluative criteria from each of the plurality of user equipment devices to the base station;
- wherein the feedback comprises preceding information;
- and
- wherein the feedback control information is configured to reduce the frequency of the feedback transmitted to the base station from each of the plurality of user equipment devices.
A method for operating a base station in a MIMO communication system comprising at least one user equipment device, wherein the base station communicates with each of the at least one user equipment devices over a respective transmission channel, the method comprising:
- broadcasting feedback control information to each of the at least one user equipment devices, the feedback control information enabling evaluation at each of the at least one user equipment devices, wherein each of the at least one user equipment device evaluation includes tracking a scheduling history for each of the at least one user equipment device;
- receiving feedback meeting a set of evaluative criteria from each of the at least one user equipment devices;
- wherein the feedback comprises preceding information;
- and
- wherein the feedback control information is configured to reduce the frequency of the feedback transmitted to the base station from each of the at least one user equipment devices.
A method for controlling feedback of precoding information in a multiple input multiple output (MIMO) communication system comprising a transmitting device and a plurality of receiving devices, wherein the transmitting device communicates with each receiving device over a respective transmission channel, the method comprising:
- generating feedback control information at the transmitting device for each receiving device, where the feedback control information comprises a schedule specifying a time slot for each receiving device to feed back preceding information to the transmitting device;
- transmitting the feedback control information to the plurality of receiving devices, where transmitting feedback control information comprises sending a synchronization signal to each receiving device over a downlink control channel, where the synchronization signal specifies the time slot for the said receiving device;
- and
- receiving one or more feedback at the transmitting device from one or more of the plurality of receiving devices, where each receiving device evaluates the feedback control information to determine a feedback constraint, wherein each receiving device evaluation of the feedback control information comprises tracking a scheduling history for each of the plurality of receiving devices;
- wherein the one or more feedback comprises preceding information;
- and
- wherein the feedback control information is configured to reduce the frequency of the one or more feedback to the transmitting device.
A method for controlling feedback in a multiple input multiple output (MIMO) communication system comprising a base station and a plurality of user equipment devices, wherein the base station communicates with each of the plurality of user equipment devices over a respective transmission channel, the method comprising:
- receiving feedback control information at each of the plurality of user equipment devices from a base station;
- evaluating the feedback control information at each of the plurality of user equipment devices, where evaluating the feedback control information comprises tracking a scheduling history for each of the plurality of user equipment devices;
- and
- transmitting feedback meeting the set of evaluative criteria from each of the plurality of user equipment devices to the base station;
- wherein the feedback comprises preceding information;
- and
- wherein the feedback control information is configured to reduce the frequency of the feedback transmitted to the base station from each of the plurality of user equipment devices.
Dependencies are inferred from the claim text.