MIMO Receiver CQI Reporting Using Precoding Matrix Transformation
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Solution Overview
Problem
In Multiple-Input Multiple-Output (MIMO) systems, calculating channel quality indicators (CQI) is challenging when the precoding matrix values and number of data streams used by the transmitter differ from those preferred by the receiver, as this requires additional computation, increasing time, power, and processing resources.
Innovation Solution
A method to estimate CQI by determining a relationship between the effective channel G and Gp, allowing for the calculation of CQI using the transmission precoding matrix W and the preferred precoding matrix Wp, thereby simplifying the computation and reducing resource requirements, especially when the data correlation matrix is approximated as a scaled identity matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver calculates CQI based on the preferred precoding matrix Wp and preferred number of data streams Np, then the CQI accurately reflects the desired channel quality, but additional computation is required when W differs from Wp and N differs from Np, increasing time, power, and processing resources
Solution Approach 1:
The receiver pre-calculates and stores the relationship between different precoding matrices and their corresponding effective channels. When CQI needs to be reported for a transmitted precoding matrix W, the receiver retrieves pre-computed transformation relationships rather than calculating from scratch, significantly reducing real-time computational complexity while maintaining CQI accuracy based on the preferred precoding matrix Wp
Solution Approach 2:
The patent introduces an intermediate effective channel Gp as a mediator between the actual effective channel G and the preferred effective channel. By determining a relationship between G and Gp based on the relationship between W and Wp, the system can accurately estimate the preferred effective channel without directly computing it, reducing computational burden while preserving measurement precision
2Measurement precision
If the receiver determines the effective channel Gp based on the preferred precoding matrix Wp, then accurate CQI can be determined, but this requires determining a relationship between G and Gp, increasing processing resources
Solution Approach 1:
The receiver pre-computes and stores transformation relationships between different precoding matrices and their corresponding effective channel relationships. When CQI reporting is needed, these pre-computed relationships are retrieved and applied, avoiding energy-intensive real-time calculations while maintaining accurate effective channel estimation
Solution Approach 2:
Instead of directly computing the preferred effective channel Gp from scratch, the system creates a transformed copy of the actual effective channel G using pre-determined transformation relationships. This copying approach with transformation significantly reduces processing energy while maintaining the accuracy needed for precise CQI determination
Data Source
AI summary
A method, a receiver and computer program product for reporting at least one channel quality indicator from a receiver to a transmitter in a MIMO system are disclosed herein. In one embodiment, the receiver receives one or more data streams transmitted by the transmitter wherein the data streams are processed by the transmitter using a transmission precoding matrix W prior to transmission to the receiver. The receiver estimates a preferred precoding matrix Wp which is preferred by the receiver and processes the received data streams using the transmission precoding matrix W, such that the effective channel G at the output of the signal processing module is dependent upon the transmission precoding matrix W used by the transmitter. The receiver determines a second effective channel Gp, uses it to determine the at least one channel quality indicator and transmits the determined at least one channel quality indicator to the transmitter.