Turbo Equalizer Switching for LTE Inter-Symbol Interference
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Solution Overview
Problem
Current turbo equalization methods in LTE systems face challenges in efficiently determining when to apply turbo equalization mode to compensate for Inter-Symbol Interference (ISI), leading to high computational complexity and variable throughput gains, especially in channels with varying delay spread and fast-fading conditions.
Innovation Solution
A method and node that predict turbo equalization gain based on instantaneous channel information and current error levels to dynamically switch the turbo equalizer on or off, reducing computational complexity and improving throughput by applying turbo equalization only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If turbo equalization mode is applied to compensate for Inter-Symbol Interference in received radio signals, then decoding performance is improved, but computational complexity increases significantly
Solution Approach 1:
The equalizer dynamically switches between turbo equalization mode and non-turbo equalization mode based on real-time channel conditions. The mode selection is controlled by a selector that monitors channel quality metrics and adjusts the equalization approach accordingly, making the system adaptive rather than static.
Solution Approach 2:
The system changes the operational parameters of the equalizer by switching between different modes (turbo and non-turbo) depending on channel conditions. This parameter change allows the system to optimize computational resources while maintaining decoding performance when needed.
2Reliability
If turbo equalization mode is applied in all channel conditions, then decoding performance is improved, but throughput varies due to unnecessary computational burden in good channel conditions
Solution Approach 1:
The system dynamically adapts the equalization mode based on channel conditions. In good channel conditions, non-turbo mode is used to maximize throughput, while in poor conditions, turbo mode is activated to ensure decoding performance, thus optimizing overall system productivity.
Solution Approach 2:
The operational parameter of the equalizer (turbo mode activation) is changed based on channel quality assessment. This parameter change enables the system to balance between decoding reliability and throughput efficiency across different channel conditions.
3Device complexity
If channel delay spread is used to determine when to apply turbo equalization, then device complexity is reduced, but measurement precision is insufficient for fast-fading conditions
Solution Approach 1:
The system changes the assessment parameter from static channel delay spread to dynamic channel quality metrics that better reflect fast-fading conditions. This parameter change improves measurement precision while maintaining reasonable determination complexity.
Solution Approach 2:
The system uses feedback from channel quality measurements to dynamically adjust the equalization mode. This feedback mechanism enables more precise assessment of channel conditions compared to relying solely on delay spread measurements.
Data Source
AI summary
The present disclosure relates to a receiving node, and to a related method for determining when to apply a turbo equalization mode to compensate for Inter-Symbol Interference in a radio signal received over a radio channel from a transmitting node. The method comprises decoding the received radio signal into a decoded signal, determining a current error level in the decoded signal, predicting a turbo equalization gain based on instantaneous channel information of the radio channel and deciding whether to apply the turbo equalization mode depending on the predicted turbo equalization gain and the determined current error level in the decoded signal.