Activated Code Channel Detection in CDMA Systems
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Solution Overview
Problem
Existing code channel detection technologies in CDMA systems suffer from low accuracy due to simple noise threshold decisions and inaccurate noise estimation, especially when interference user signals are weak.
Innovation Solution
The method involves de-scrambling and de-spreading of received signals according to a spreading code tree, acquiring decision parameters from symbol energy comparisons of adjacent nodes, and detecting modulation modes to determine activated code channels, thereby improving detection accuracy by assessing energy transfer paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple noise threshold comparison is used for code channel detection, then detection process is simple, but detection accuracy is low when noise estimation is inaccurate or interference user signal is weak
Solution Approach 1:
The patent segments the detection process into multiple independent stages: first comparing symbol energy with noise threshold to obtain first decision parameter, then comparing symbol energy of adjacent nodes to obtain second decision parameter, and finally combining both parameters with modulation mode detection results. This segmentation allows each stage to focus on specific aspects of detection, improving overall accuracy while maintaining manageable complexity.
Solution Approach 2:
The patent transitions from one-dimensional detection (single noise threshold comparison) to multi-dimensional detection by introducing multiple comparison dimensions: symbol energy vs. noise threshold, symbol energy of adjacent nodes vs. each other, and modulation mode detection results. This dimensional expansion enables more comprehensive assessment of code channel activation status, significantly improving detection accuracy in weak signal conditions.
2Reliability
If advanced interference user suppression algorithm is used to improve system capacity, then more interference user information is required, but system complexity increases
Solution Approach 1:
The patent performs preliminary actions by detecting and identifying activated code channels before interference suppression processing. By using the multi-parameter detection method to accurately identify which code channels are active, the system prepares interference user information in advance, reducing the complexity of subsequent interference suppression algorithms while maintaining system capacity improvements.
Data Source
AI summary
The present invention provides an activated code channel detection method. The method includes: performing de-scrambling and de-spreading on a received signal according to a node corresponding to a current spreading factor, obtaining symbol energy corresponding to each node; acquiring a first decision parameter and a second decision parameter according to symbol energy of two adjacent nodes of a same parent node and a pre-acquired noise threshold, where the first decision parameter is a comparison result of comparing the noise threshold with symbol energy of each of the two adjacent nodes, and the second decision parameter is a comparison result of comparing the symbol energy of the two adjacent nodes; detecting modulation modes of code channels corresponding to the two adjacent nodes, obtaining a modulation mode detection result; and executing activated code channel detection according to the first decision parameter, the second decision parameter, and the modulation mode detection result.