Frame Sync Resampling for Interference-Free Timing Detection
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Solution Overview
Problem
Existing frame synch detection methods in wireless networks face radio interference issues due to receivers operating at XO-integer-divided sample rates, leading to receiver de-sensing and inaccurate time of arrival measurements.
Innovation Solution
A data resampler circuit using a re-timer engine and correlation circuit to perform frame synch detection at a pseudo clock rate that approximates an XO-integer-divided sample rate, avoiding radio interference by resampling data at a non-integer sample rate and using fractional conversion ratios to maintain precise timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If receivers operate at XO-integer-divided sample rates for frame synch detection, then timing synchronization is simplified, but radio interference occurs causing receiver de-sensing and inaccurate time of arrival measurements
Solution Approach 1:
The patent introduces a data resampler circuit as an intermediary component between the receiver front-end and the frame synch detection circuitry. This resampler converts samples from the XO-integer-divided sample rate to a non-integer sample rate, allowing the receiver to avoid operating directly at the problematic integer-divided rate while still enabling accurate frame synchronization. The resampler acts as a mediator that decouples the conflicting requirements of simple timing synchronization and radio interference avoidance.
2Device complexity
If frame synch detection is performed at XO-integer-divided sample rates, then correlation processing is simplified, but measurement precision of time of arrival deteriorates due to radio interference
Solution Approach 1:
Instead of operating the receiver at the XO-integer-divided sample rate and then attempting to correct interference issues, the patent inverts the approach by first resampling the received signal at a non-integer rate that avoids the interference problem, and then performing correlation processing at this alternative rate. This inversion allows frame synch detection to achieve both acceptable complexity and high measurement precision by avoiding the problematic sample rate entirely.
3Object-affected harmful factors
If data is resampled at non-XO-integer-divided sample rates to avoid radio interference, then frame synch detection accuracy is maintained through correlation, but device complexity increases due to resampling circuitry
Solution Approach 1:
The patent changes the sampling rate parameter from a fixed XO-integer-divided value to a variable non-integer rate that can be adjusted based on the specific operating conditions. The data resampler circuit implements this parameter change by dynamically selecting appropriate resampling factors to convert between different sample rates. This parameter flexibility allows the system to avoid radio interference while maintaining manageable device complexity through efficient resampling algorithms.
Data Source
AI summary
A device includes a receiver to receive a packet over a channel at a first frequency and generate a sampled stream of data at a first sample rate corresponding to the first frequency. A data resampler circuit includes a re-timer engine to determine, using a ratio between the first sample rate and a crystal oscillator (XO)-divided sample rate, re-timer values. The data resampler circuit includes a time shifting circuit to re-sample data values of the sampled stream of data associated with locations of the plurality of re-timer values. A correlation circuit uses the re-sampled data values, and the re-timer values to match an expected data pattern to a corresponding data pattern detected in a frame of the packet.