Adaptive Path Selection for Multipath Interference Cancellation
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Solution Overview
Problem
In WCDMA and HSDPA wireless communication systems, interference from multipath signals and signals from other cells leads to multiple access interference (MAI), which degrades signal quality and can result in suboptimal performance gains or even performance degradation when interference cancellation is not carefully managed.
Innovation Solution
The introduction of path admission logic to selectively control interference cancellation, assessing and bypassing weak or noisy signal paths, and disabling interference cancellation logic when it would adversely impact the desired signal, thereby improving signal quality and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interference cancellation is applied to all signal paths, then signal quality from strong interfering paths is improved, but weak or noisy paths introduce additional noise that degrades overall signal quality
Solution Approach 1:
The system dynamically changes the parameter of interference cancellation application by assessing signal path strength and noise characteristics, selectively applying cancellation only to paths meeting predefined criteria (e.g., signal strength above threshold, signal-to-noise ratio above threshold) rather than uniformly to all paths
Solution Approach 2:
The system implements feedback through path admission logic that continuously evaluates signal path characteristics and adjusts which paths are admitted to interference cancellation processing, using measured signal strength and noise levels to make real-time decisions about path inclusion
2Reliability
If interference cancellation processing is applied to all received paths, then interference suppression is improved, but computational complexity and processing overhead increase
Solution Approach 1:
The system extracts only the necessary subset of signal paths that require interference cancellation processing by applying admission criteria, separating paths that benefit from cancellation from those that do not, thereby reducing overall processing complexity while maintaining interference suppression effectiveness
3Reliability
If multiple signal paths are processed through interference cancellation, then interference from multiple sources is reduced, but power consumption increases
Solution Approach 1:
The system applies partial action by selectively processing only those signal paths that meet admission criteria rather than all received paths, performing interference cancellation to the extent necessary (on qualifying paths) while avoiding unnecessary processing on paths that would not benefit, thereby reducing power consumption while maintaining effective interference cancellation
Data Source
AI summary
Adaptive path selection for interference cancellation is provided for wireless communication devices. Signal strength metrics are obtained for each of multiple signal paths. One or more of the signal paths are selected as cancellation candidates in response to determining that the signal paths are associated with a strong interfering path based at least in part on the signal strength metrics for the signal paths and threshold criteria. Cancellation is enabled for an estimated signal generated using the signal paths in response to the signal paths being selected as cancellation candidates.