Finger Allocation Algorithm for W-CDMA Multipath Receiver
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Solution Overview
Problem
RAKE receivers in W-CDMA systems face challenges in efficiently allocating fingers to multipath regions due to unresolvable paths and limited resources, leading to suboptimal performance and increased power consumption.
Innovation Solution
A finger allocation algorithm that detects multipath regions based on power delay profiles, uses an area-based weighting scheme to determine the number of allocated fingers, and strategically places fingers within these regions to maximize signal energy capture, even in unresolvable scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fingers are allocated to all detected multipath regions, then diversity gain is improved, but power consumption increases and resources are wasted on unresolvable paths
Solution Approach 1:
The patent changes the parameter of finger allocation from a uniform distribution to an area-based weighted distribution. By calculating the area under each multipath region in the power delay profile and allocating fingers proportionally to these areas, the system optimizes resource distribution to focus on significant paths while avoiding waste on negligible ones, thereby reducing power consumption while maintaining diversity gain.
2Ease of operation
If fingers are allocated uniformly across all multipath regions, then resource distribution is simplified, but performance is suboptimal due to unequal path significance
Solution Approach 1:
The patent applies local quality by making the finger allocation non-uniform and adaptive to local characteristics of each multipath region. The area-based weighting scheme assigns different allocation ratios to different regions based on their individual areas under the power delay profile, ensuring that regions with higher signal energy receive more fingers while maintaining a systematic allocation process.
3Reliability
If the number of fingers is increased to capture all resolvable paths, then diversity gain is maximized, but device complexity and resource requirements increase
Solution Approach 1:
The patent implements partial action by allocating fingers to only those multipath regions that meet a minimum area threshold, rather than uniformly allocating to all detected regions. The area-based weighting scheme naturally limits finger allocation to significant paths, avoiding the complexity of managing fingers for negligible paths while still capturing the majority of signal energy for diversity gain.
Data Source
AI summary
A technique for allocating fingers in a path searcher of a multipath receiver involves determining a required number of fingers for each multipath region, determining a number of allocated fingers for each multipath region according to an area-based weighting scheme such that each multipath region that is allocated fewer than its required number of fingers is deemed to have a non-zero residual area, allocating any surplus fingers to multipath regions having non-zero residual areas until either no surplus fingers remain or each multipath region is allocated its required number of fingers, and placing any fingers allocated to each multipath region within the multipath region. Placing the fingers in un-resolvable path scenario involves detecting path location at the edges of multipath region; placing fingers at the edges and placing remaining fingers uniformly between the first and the last path such that the there is a minimum placement separation between the fingers.