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US 9,319,118 B2Granted
Technology for CSI feedback in a MIMO communication system
OwnerYuan Zhu, Xiaogang Chen +1inventors
InventorsYuan Zhu, Xiaogang Chen, Qinghua Li
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Abstract
Technology for channel state information (CSI) feedback in a multiple-input multiple-output (MIMO) communication system is disclosed. A method comprises receiving, at a mobile device, a dynamic channel state information (CSI) feedback switch signal from a transmission station that identifies a selected CSI feedback state for the mobile device. A process for selecting a precoding matrix indicator (PMI) and a rank indicator is identified based on the CSI feedback switch signal as either a process configured for MU-MIMO reception or single-user (SU) MIMO reception of a downlink signal at the mobile device.
Claims19
An apparatus, comprising:
- a receiver arranged to receive wireless downlink communications comprising one or more data streams over a transmission band, each transmission characterized by a rank r specifying a number of data streams to be simultaneously communicated over the transmission band in multi-user multiple-input multiple output (MU-MIMO);
- a memory containing a multiple rank codebook;
- a processor;
- and
- a CSI feedback module operable on the processor to:
- quantize a principle Eigen vector in a precoding matrix index i0 for lowest rank transmissions;
- set a precoding matrix index ir for a higher level rank transmission based upon the principle Eigen vector and a maximum cross correlation of each column of the codebook with the principle Eigen vector to identify a selected precoding matrix indicator (PMI) for the higher level rank transmission;
- and
- select a rank for receiving the downlink communications based on the PMI for the higher level rank transmission.
6 more elements
An article, comprising a non-transitory computer-readable storage medium containing instructions that if executed by a processor enable a system to:
- determine a precoding matrix indicator (PMI) and a rank indicator (RI) using a first process configured for single-user multiple-input multiple-output (SU-MIMO) reception of a downlink signal;
- determine a precoding matrix indicator (PMI) and a rank indicator (RI) using a second process configured for multi-user multiple-input multiple-output (MU-MIMO) reception of a downlink signal, wherein the second process is different from the first process;
- receive a dynamic channel state information (CSI) feedback switch signal from a transmission station identifying one of the first process for SU-MIMO or the second process for MU-MIMO to determine a PMI to report and an RI to report;
- and
- communicate at least one of the PMI to report and the RI to report to the transmission station, wherein the PMI to report and RI to report are determined using one of the first process or the second process identified from the CSI feedback switch signal, wherein the second process includes:
- quantizing a principle Eigen vector in a precoding matrix index i0 of a codebook for lowest rank transmissions;
- setting a precoding matrix index ir for a higher level rank transmission based upon the principle Eigen vector and a maximum cross correlation of each column of the codebook with the principle Eigen vector to identify a selected precoding matrix indicator (PMI) for the higher level rank transmission;
- and
- selecting a rank for receiving downlink communications based on the PMI for the higher level rank transmission.
6 more elements
A method for selecting CSI feedback in a multiple-input multiple-output (MIMO) communication system, comprising:
- receiving, at a mobile station, a dynamic channel state information (CSI) feedback switch signal from a transmission station that identifies a selected CSI feedback state for the mobile station;
- for a first CSI feedback state, selecting a precoding matrix indicator (PMI) and a rank indicator (RI) using a first process configured for single-user multiple-input multiple-output (SU-MIMO) reception of a downlink signal for a first state of the CSI feedback switch signal;
- for a second CSI feedback state, selecting a precoding matrix indicator (PMI) and a rank indicator (RI) using a second process configured for multi-user multiple-input multiple-output (MU-MIMO) reception of a downlink signal for a second state of the CSI feedback switch signal, wherein the second process is different from the first process;
- and
- communicating at least one of a PMI to report and an RI to report to the transmission station, wherein the PMI to report and RI to report are determined using one of the first process or the second process based on the selected CSI feedback state, wherein the second process includes:
- quantizing a principle Eigen vector in a precoding matrix index i0 of a codebook for lowest rank transmissions;
- setting a precoding matrix index it for a higher level rank transmission based upon the principle Eigen vector and a maximum cross correlation of each column of the codebook with the principle Eigen vector to identify a selected precoding matrix indicator (PMI) for the higher level rank transmission;
- and
- selecting a rank for receiving downlink communications based on the PMI for the higher level rank transmission.
6 more elements
Dependencies are inferred from the claim text.