LTE MIMO CQI Feedback Quantization for Variable Delta SINR
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Solution Overview
Problem
The existing method of channel quality information (CQI) feedback in MIMO systems, specifically the 'CQIbase+CQIdelta' approach, suffers from performance loss due to significant variability in the dynamic range of CQIdelta in different configurations and channel situations, limiting its compression potential.
Innovation Solution
A configurable quantization method for CQIdelta is introduced, using adjustable step sizes and offsets based on antenna configurations and channel conditions, allowing for flexible dynamic range management through cell-specific or UE-specific configuration, and employing uniform or non-uniform quantization tables to map CQIdelta values to SINR differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If CQIbase and CQIdelta are used for feedback in two-codeword MIMO transmission, then feedback overhead is reduced by assigning fewer feedback bits for CQIdelta, but performance loss occurs due to limited compression potential when dynamic range of CQIdelta varies significantly
Solution Approach 1:
The patent applies dynamics by making the quantization step size configurable rather than fixed. The step size for CQIdelta quantization can be adjusted based on channel conditions and configuration, allowing the system to adapt to varying dynamic ranges. This resolves the contradiction by enabling both compression (when dynamic range is small) and accuracy (when dynamic range is large) through dynamic parameter adjustment.
Solution Approach 2:
The patent changes the parameter of quantization step size from a fixed value to a configurable parameter. By allowing the step size to be modified based on channel conditions and codeword characteristics, the system can optimize the balance between feedback overhead and performance. This parameter change enables the quantization to adapt to different scenarios, resolving the trade-off between compression and accuracy.
2Ease of manufacture
If fixed step size is used for CQIdelta quantization, then quantization process is simple, but accuracy is reduced when dynamic range varies significantly across different configurations and channel situations
Solution Approach 1:
The patent transforms the static quantization step size into a dynamic, configurable parameter. The step size can be adjusted based on channel conditions, antenna configuration, and observed codeword characteristics. This dynamic approach maintains quantization process simplicity while significantly improving accuracy by adapting to varying dynamic ranges in different scenarios.
Solution Approach 2:
The patent modifies the quantization step size parameter from a fixed constant to a configurable variable. This parameter change allows the system to optimize quantization accuracy for different channel conditions and configurations while maintaining implementation simplicity through standardized configuration mechanisms.
3Measurement precision
If more feedback bits are assigned for CQIdelta to cover larger dynamic range, then quantization accuracy is improved, but feedback overhead increases
Solution Approach 1:
The patent changes the approach from increasing bit allocation to optimizing step size configuration. By adjusting the quantization step size parameter, the system can achieve accurate representation of CQIdelta with the existing bit allocation. This parameter optimization resolves the contradiction by improving accuracy through better quantization design rather than increased overhead.
Solution Approach 2:
The patent applies dynamics by making the quantization step size adaptive to channel conditions and configuration. This allows the system to maintain high quantization accuracy across varying dynamic ranges without requiring increased feedback bits, as the step size adjusts to match the actual CQIdelta range in each scenario.
Data Source
AI summary
A quantization method of transmission of channel quality information (CQI) includes measuring two measurements SINRs and calculating a difference (i.e., Delta SINR) between the two measurements of the SINRs; determining a CQIbase (base channel quality information) based on one of the two measurements SINRs and a known quantization table for the CQIbase, and simultaneously receiving cell-specific or UE-specific parameters transmitted from a base station and configuring a quantization table defining a mapping method of CQIdelta (delta channel quality information) and the Delta SINR and determining the CQIdelta based on the obtained Delta SINR and the configured quantization table; and transmitting the resulting CQIdelta and CQIbase.