I/Q Data Compression Using FFT and Polar Quantization
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Solution Overview
Problem
The existing methods for converting radio frequency signals into digital data for transmission through limited-speed transmission lines are inefficient, leading to limited channel capacity and increased noise interference due to compression, especially in frequency division methods like LTE.
Innovation Solution
A digital data compression and decompression method and device that perform frequency domain conversion using FFT and IFFT blocks, followed by quantization in polar coordinates to optimize noise reduction and data transmission efficiency, reducing the amount of data transmitted and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If digital data is transmitted through limited-speed transmission lines, then transmission can be achieved, but transmission efficiency is low and channel capacity is limited
Solution Approach 1:
The patent extracts and transmits only the essential signal characteristics by converting time-domain digital I/Q data into frequency-domain coefficients through FFT transformation. This extraction process identifies and transmits only the meaningful signal components while discarding redundant information, thereby reducing the quantity of transmitted data while maintaining transmission efficiency.
Solution Approach 2:
The patent applies parameter changes by transforming the data representation from time-domain samples to frequency-domain coefficients. This parameter transformation fundamentally changes how the signal information is encoded, allowing for more efficient compression and transmission through the limited-speed transmission lines.
2Productivity
If compression is applied to increase channel capacity, then more channels can be transmitted, but noise interference increases
Solution Approach 1:
The patent introduces frequency-domain coefficient representation as an intermediary between the original signal and the transmitted data. This intermediary form allows for selective quantization and compression that preserves signal integrity while reducing noise interference. The intermediary representation enables differential quantization that maintains signal-to-noise ratio even at reduced data rates.
Solution Approach 2:
By changing the parameter representation from time-domain amplitude values to frequency-domain magnitude and phase components, the patent enables more efficient quantization strategies. The magnitude and phase parameters can be quantized differently based on their statistical properties, reducing overall quantization noise while maintaining channel capacity.
3Quantity of substance
If conventional quantization is used, then data can be compressed, but signal-to-noise ratio deteriorates especially for low power signals
Solution Approach 1:
The patent applies local quality by using differential quantization where the magnitude and phase components are quantized with different precision levels. The magnitude component, which contains the primary signal energy information, is quantized with higher precision using floating-point methods, while the phase component uses fixed-point quantization. This localized differentiation of quantization quality preserves the signal-to-noise ratio for low power signals while achieving overall data compression.
4Productivity
If more channels are transmitted through limited transmission lines, then channel capacity increases, but transmission speed requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the signal processing into distinct stages: FFT transformation, magnitude-phase separation, differential quantization, and packed encoding. This segmentation allows each stage to optimize for its specific function, achieving maximum compression efficiency. The segmented approach enables multiple channels to be transmitted through the limited-speed lines by minimizing the data volume of each channel.
Data Source
AI summary
There is provided a digital data compression device including a domain converter configured to perform frequency domain conversion on input digital I/Q data and output coefficient data corresponding to the digital I/Q data; a data converter configured to receive the coefficient data output from the domain converter and convert the input coefficient data of Cartesian coordinates into coefficient data of polar coordinates; and a quantizer configured to quantize the coefficient data of the polar coordinates output from the data converter.