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.
Claims20
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.
An article, comprising a 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 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 process configured for multi-user multiple-input multiple-output (MU-MIMO) reception of a downlink signal;
- receive a dynamic channel state information(CSI) feedback switch signal from a transmission station identifying one of the SU-MIMO process and the MU-MIMO process to determine the PMI and RI;
- and
- communicate at least one of the PMI and the RI to the transmission station, wherein the PMI and RI are determined using the process identified from the CSI feedback switch signal.
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 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 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;
- and
- communicating at least one of the PMI and the RI to the transmission station based on the selected CSI feedback state.
Dependencies are inferred from the claim text.