CQI Reporting for MIMO Transmission Using Power Distribution
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Solution Overview
Problem
In wireless communication systems, accurately determining and reporting Channel Quality Indicator (CQI) information for MIMO transmissions is challenging due to the non-linear relationship between transmit power and Signal-to-Interference-and-Noise Ratio (SINR), which affects data transmission performance.
Innovation Solution
The user equipment (UE) determines CQI information based on transmit power per channelization code, assuming a uniform distribution across transport blocks and channelization codes, and sends this information to the Node B, which then adjusts transmission parameters accordingly to improve SINR estimation and data block processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE estimates SINR based on available transmit power and number of channelization codes, then CQI reporting accuracy is improved, but the complexity of SINR estimation increases due to non-linear relationship
Solution Approach 1:
The patent transforms the non-linear SINR estimation problem into a linear calculation by changing the parameter representation to dB domain. The SINR is calculated as: SINR (dB) = POVSF (dB) - path loss (dB) - shadowing (dB) + interference margin (dB). This parameter transformation allows accurate CQI reporting while simplifying the estimation complexity through straightforward arithmetic operations in the logarithmic domain.
2Ease of operation
If the UE assumes uniform distribution of transmit power across transport blocks and channelization codes, then CQI determination is simplified, but accuracy may be reduced in non-uniform power allocation scenarios
Solution Approach 1:
The patent applies preliminary action by having the UE calculate and report CQI based on the assumed uniform power distribution before the actual non-uniform power allocation occurs. The UE determines POVSF assuming uniform distribution, calculates corresponding CQI values, and reports these to the Node B. The Node B then uses these pre-calculated CQI values with its knowledge of the actual non-uniform power allocation to achieve accurate SINR estimation and transport block size determination.
Data Source
AI summary
Techniques for determining and reporting channel quality indicator (CQI) information are described. A user equipment (UE) may determine precoding information and channel quality information to be reported to a base station. The UE may jointly encode the precoding information and the channel quality information to obtain coded data. The UE may send the coded data to the base station.