Multipath Channel Delay Search Using Shifting Time Windows
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Solution Overview
Problem
Existing spread spectrum telecommunication systems face challenges in accurately determining delays in multipath channels, especially in mobile environments where channel conditions are subject to fading and motion, leading to inefficiencies in Rake receiver performance.
Innovation Solution
A method is introduced where a receiver performs delay searches within a time window shorter than the maximum delay spread, shifting this window periodically to cover the entire delay range, allowing for reduced complexity in the delay searcher design and increased precision by focusing more searches on the middle and central portions of the delay spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a delay searcher performs delay searches over the entire maximum delay spread, then all delays are identified, but the complexity of the delay searcher increases
Solution Approach 1:
The delay search range is divided into multiple time windows, each covering a portion of the maximum delay spread. The delay searcher performs searches within each window separately, reducing the complexity required for each individual search while collectively covering the entire delay range through sequential or parallel window processing.
Solution Approach 2:
The patent introduces a time-domain segmentation dimension by dividing the delay spread into multiple time windows. This allows the delay searcher to operate with reduced complexity within each window while maintaining comprehensive coverage through the temporal arrangement of windows, effectively adding a dimensional approach to the search process.
2Device complexity
If a delay searcher uses a time window shorter than the maximum delay spread, then the searcher complexity is reduced, but not all delays may be identified in a single search
Solution Approach 1:
The maximum delay spread is segmented into multiple time windows, each handled by the delay searcher independently. This segmentation allows the searcher to operate with reduced complexity within each window while ensuring complete delay identification through the collective coverage of all windows.
Solution Approach 2:
The delay search process maintains continuity by systematically moving through multiple time windows to cover the entire delay spread. The searcher continuously performs searches across adjacent windows, ensuring no delays are missed while maintaining reduced complexity within each search operation.
3Measurement precision
If delay searches are performed frequently over the entire delay range, then delay tracking accuracy is improved, but the processing time and energy consumption increase
Solution Approach 1:
The delay range is segmented into time windows, allowing the searcher to perform frequent, rapid searches within each window without requiring full-range searches. This segmentation enables more frequent updates with reduced processing time per search, improving overall delay tracking accuracy while reducing total processing time.
Solution Approach 2:
The delay searcher performs periodic searches within each time window at optimized intervals. By conducting multiple shorter periodic searches within windows rather than fewer long full-range searches, the system achieves improved delay tracking accuracy with reduced processing time and energy consumption.
Data Source
AI summary
A method of finding delays of a multipath channel for receiving a spread spectrum signal, the multipath channel having a maximum delay spread, includes the steps of performing a first delay search within a time window in order to find first delays, the time window being located within the maximum delay spread, storing of the first delays in a delay storage, shifting the time window within the maximum delay spread, performing a second delay search within the shifted time window in order to find second delays and updating the delay storage on the basis of the second delays.