Link Quality Measurement Using Mutual Information Per Bit
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Solution Overview
Problem
In MIMO wireless communication systems, measuring link quality accurately is challenging when using a Maximum Likelihood (ML) detector, as existing methods like MMSE detection result in errors at high SNR, affecting channel status information feedback and link throughput.
Innovation Solution
A method and apparatus for measuring link quality by determining modulation type, searching pre-stored parameters, and calculating channel capacity for each stream without calculating SINR, using channel and modulation information to calculate Mutual Information per Bit (MIB) and channel capacity, effectively parameterizing the modulation types to avoid SINR calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If MMSE detection method is used to measure link quality, then the measurement process can be simplified, but measurement accuracy deteriorates at high SNR due to interference signal misinterpretation
Solution Approach 1:
The patent changes the fundamental parameter used for link quality measurement from SINR (Signal-to-Interference-plus-Noise Ratio) to MIB (Mutual Information per Bit). This parameter transformation allows accurate measurement at high SNR by using ML detector outputs directly, avoiding the interference misinterpretation problem that plagues SINR-based methods like MMSE detection.
2Measurement precision
If SINR calculation is performed for each symbol in MIMO system, then link quality can be measured, but calculation complexity increases due to interference signal processing requirements
Solution Approach 1:
The patent extracts the essential link quality information directly from the ML detector output without performing complex SINR calculations. By taking out the mutual information per bit metric from the detector output, the system achieves accurate link quality measurement while avoiding the computational complexity of interference signal processing required for traditional SINR methods.
3Reliability
If ML detector is used to improve MIMO receiver performance, then detection accuracy improves, but link quality measurement becomes difficult because interference signals are joint-detected rather than treated as noise
Solution Approach 1:
The patent introduces MIB (Mutual Information per Bit) as an intermediary metric that bridges ML detector output and link quality measurement. This intermediary allows the system to leverage the high detection accuracy of ML detectors while obtaining accurate link quality measurements, as MIB can be calculated from ML detector outputs without requiring interference signal separation.
Data Source
AI summary
A method and an apparatus for measuring a link quality in a wireless communication are provided. The method of a receiver for measuring the link quality in the wireless communication system includes determining a modulation type for each of at least one reception stream received through at least one antenna based on a modulation order and channel information regarding each of signals transmitted from a plurality of transmission antennas, searching for a parameter corresponding to the determined modulation type from a pre-stored parameter table in which parameters for each modulation type are stored, and calculating a channel capacity for each of the at least one reception streams received through the at least one antenna by using the searched parameter.