PN Code Tracking Circuit Segmentation for TDS-OFDM
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Solution Overview
Problem
In time domain synchronous orthogonal frequency division multiplexing (TDS OFDM) systems, the reliability of pseudo noise code detection is low due to non-additive white Gaussian noise, leading to incorrect detection and increased computational load when trying to improve accuracy through higher sampling rates.
Innovation Solution
A pseudo noise code tracking circuit that performs correlation twice using a first correlator, a storage device, and a second correlator to generate a shift value, allowing for accurate frame number determination and local PN code updating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correlation is performed with a higher sampling rate to raise detection accuracy, then measurement precision is improved, but device complexity increases due to significant increase in computational load
Solution Approach 1:
The patent divides the correlation process into two separate stages: first correlating PN codes from different frames with a local PN code to generate correlation values, then correlating these correlation values with each other to detect the peak position. This segmentation allows accurate detection without requiring excessively high sampling rates, thereby reducing computational load while maintaining detection accuracy.
2Reliability
If correlation is performed with a higher sampling rate to raise detection accuracy, then reliability is improved, but use of energy increases due to significant increase in computational load
Solution Approach 1:
By segmenting the correlation operation into two steps (first correlating PN codes with local PN code, then correlating the resulting correlation values), the patent achieves reliable detection under non-additive white Gaussian noise conditions without requiring prohibitively high sampling rates, thus reducing energy consumption while maintaining reliability.
3Measurement precision
If correlation is performed with a higher sampling rate to raise detection accuracy, then measurement precision is improved, but loss of time increases due to significant increase in computational load
Solution Approach 1:
The patent segments the correlation process into two manageable stages, which reduces the computational burden at each stage compared to performing a single high-resolution correlation. This allows for accurate PN code detection without excessive processing time, as each segmented correlation operation can be performed more efficiently.
Data Source
AI summary
A pseudo noise code (PN code) tracking circuit includes a first correlator, a storage device, a second correlator and a detector. The first correlator is utilized for performing correlation on a first PN code in a first signal frame with a local PN code to generate a first set of correlation values, and for performing correlation on a second PN code in a second signal frame with the local PN code to generate a second set of correlation values. The storage device is coupled to the first correlator for storing the first and second sets of correlation values. The second correlator is coupled to the storage device for performing correlation on the first set of correlation values with the second set of correlation values to generate a shift value. The detector is coupled to the second correlator for generating a frame number according to the shift value.