Uplink Ranging Code Detection Using Segmented Transform and Cross-Correlation
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Solution Overview
Problem
Conventional apparatuses for detecting uplink ranging codes in wireless communication systems face complexity in data processing and inaccuracy in estimating time offsets, especially when dealing with large ranging code books and noisy environments.
Innovation Solution
An apparatus that includes a first transform unit, a cross-correlation unit, a switch, a screening unit, and a detection unit, which selectively processes data through optimal or sub-optimal modes based on predetermined criteria to reduce resource consumption and improve accuracy by using pattern analysis instead of peak location for time offset estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional apparatus processes all outputs from the cross-correlation unit through the IFFT unit, then complete ranging code detection is achieved, but data processing complexity and resource consumption increase significantly
Solution Approach 1:
The patent segments the ranging code detection process into two stages: a first IFFT operation on received signals followed by cross-correlation with code book sequences, and a second IFFT operation only on matched outputs. This segmentation allows the system to process only relevant data through the computationally intensive second transform, reducing overall complexity while maintaining detection completeness.
Solution Approach 2:
The patent performs preliminary cross-correlation processing before the second IFFT operation to identify and isolate potential ranging code matches. By pre-processing the data through cross-correlation with known code book sequences, the system prepares the input for the second IFFT in advance, ensuring that only necessary computations are performed in the final transform stage.
2Ease of operation
If the time offset is estimated by the highest peak location in the process domain, then the estimation process is simple, but accuracy deteriorates in low over-sampling environments with noise
Solution Approach 1:
The patent introduces cross-correlation with code book sequences as an intermediary step between signal transformation and time offset estimation. Instead of directly estimating time offset from the transformed signal peaks, the system first correlates the signal with known ranging code sequences, using the correlation results to identify the true time offset location even in noisy, low over-sampling conditions.
3Adaptability or versatility
If a large ranging code book is used to cover all possible codes, then code detection coverage is improved, but processing time and computational resources increase
Solution Approach 1:
The patent extracts only the relevant portion of the code book processing by performing cross-correlation to identify which code book sequences actually match the received signal. Instead of processing all code book sequences through the complete detection pipeline, the system extracts and processes only those sequences that show correlation matches, significantly reducing processing time while maintaining comprehensive code coverage capability.
Data Source
AI summary
An apparatus for detecting uplink ranging codes includes a first transform unit for transforming data received from a mobile station to generate first outputs; a cross-correlation unit for comparing the first outputs with possible ranging codes to generate second outputs; a screening unit for selectively passing the second outputs representing parts of the received data that match the possible ranging codes; a second transform unit for transforming the second outputs from the screening unit to generate third outputs; and a detection unit for detecting the ranging codes for the received data based on the third outputs.