Wireless Receiver Interference Scenario Selection
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Solution Overview
Problem
Conventional CDMA receivers experience performance degradation due to loss of orthogonality between channelisation codes in the presence of multi-path propagation, especially in WCDMA systems, which affects high data rate transmission in HSDPA standards, and existing equalization methods are complex and assume specific noise statistics.
Innovation Solution
A method for selecting an interference scenario based on dominant interfering cells to adapt receiver processing functions, using the number of dominant cells and their power ratios to choose between MMSE and LS equalizers, and adjust time averaging windows based on Doppler estimates, allowing for robust interference scenario selection and appropriate signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chip level channel equalisation processing is used to improve performance over conventional rake processing, then signal detection accuracy is improved, but implementation complexity increases
Solution Approach 1:
The patent implements dynamic selection between different equalisation processing modes (chip level equalisation, symbol level equalisation, and rake processing) based on real-time channel conditions and interference scenarios. The receiver adapts its processing complexity by selecting the appropriate equalisation strategy for each received signal, thereby optimizing the balance between detection accuracy and computational load.
Solution Approach 2:
The patent changes the processing parameters (equalisation type, time averaging window size, Doppler estimate thresholds) based on detected interference scenarios and channel conditions. By adjusting these parameters dynamically, the system achieves high detection accuracy in challenging conditions while maintaining lower complexity in favorable conditions.
2Measurement precision
If MMSE equaliser is used to minimize mean-square error at equaliser output, then estimation accuracy is improved, but assumptions about noise statistics reduce robustness
Solution Approach 1:
The patent employs feedback mechanisms where the receiver detects interference scenarios, estimates Doppler frequencies, and uses this information to select appropriate equalisation strategies. This feedback loop allows the system to adapt to different noise statistics and interference conditions, selecting MMSE when appropriate and alternative methods when robustness is needed.
Solution Approach 2:
The system changes processing parameters based on detected conditions - using MMSE equalisation with specific time averaging windows when channel conditions support it, and switching to other methods when interference patterns suggest different noise statistics. This parameter adaptation resolves the contradiction between accuracy and robustness.
3Speed
If time averaging window is adjusted to track time variations, then tracking performance is improved, but estimation errors increase with smaller windows
Solution Approach 1:
The patent dynamically adjusts the time averaging window size based on estimated Doppler frequencies and detected interference scenarios. When channel conditions indicate rapid variations (high Doppler), the system uses smaller windows for faster tracking. When conditions are more stable, larger windows improve estimation accuracy. This dynamic adaptation resolves the trade-off between tracking speed and accuracy.
Data Source
AI summary
A method, receiver and program for processing a signal received using a wireless communication channel by a receiver in a wireless cellular network. The method comprises: receiving signal samples of a signal to be processed from a serving cell; identifying a set of dominant interfering cells generating an interfering signal above a level; using the number of cells in the set to select an interference scenario; and using the selected interference scenario and at least one parameter related to the serving cell and the interfering cells to select a processing function for processing the signal.