Dynamic Quantization Interval Adjustment for Digital Communication
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Solution Overview
Problem
Conventional digital communication systems, particularly CDMA-type systems, face performance degradation due to suboptimal quantization intervals set for worst-case scenarios, leading to inefficient signal reception and decoder performance.
Innovation Solution
An apparatus and method that measure the dynamic range of demodulated data to actively adjust the quantization interval, optimizing it based on the demodulation type, packet codeword repetition, and wireless channel conditions, using a quantization level generator and input signal converter to scale signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the quantization interval is determined based on the worst case to accommodate the entire dynamic range of decoder input signals, then the quantizer can handle all modulation types and channel conditions, but the quantization cannot be optimized in normal cases leading to degraded decoder performance
Solution Approach 1:
The patent implements dynamic adjustment of the quantization interval by introducing a scale factor that is calculated based on the standard deviation of the input signal. The quantization interval is no longer fixed but adapts dynamically to the actual signal characteristics, allowing the system to optimize quantization precision for each specific channel condition and modulation type while maintaining versatility across different scenarios
Solution Approach 2:
The patent changes the quantization parameter (interval) based on the statistical properties of the input signal. By calculating the standard deviation and using it to determine an appropriate scale factor, the system adjusts the quantization interval parameter to match the actual signal dynamic range, thereby improving quantization precision without sacrificing adaptability
2Reliability
If the dynamic range of decoder input is set large enough to accommodate the entire dynamic range considering all worst-case scenarios, then the receiver can handle maximum signal variations, but the quantization efficiency is reduced in normal operating conditions
Solution Approach 1:
The system dynamically adjusts the quantization scale factor based on the measured standard deviation of the input signal, allowing the decoder to efficiently process signals under normal operating conditions while maintaining the capability to handle extreme variations when they occur, thus improving overall processing efficiency without compromising reliability
3Device complexity
If the quantization interval is fixed based on the number of effective bits used by the decoder, then the quantizer structure remains simple, but the signal-receiving performance of the decoder is lowered due to suboptimal quantization
Solution Approach 1:
The patent modifies the quantization interval parameter by introducing a scale factor that is calculated from the signal's standard deviation. This parameter change allows the quantizer to achieve optimal quantization precision for the given signal characteristics while maintaining a relatively simple structure, as the scale factor calculation and application are computationally efficient operations
Data Source
AI summary
Disclosed is an apparatus and a method for actively adjusting the quantization interval of signals inputted to a decoder in a digital communication system. The apparatus includes a quantization level generator for measuring a dynamic range of received packet data and calculating a corresponding scale factor, and an input signal converter for scaling a received data signal according to the scale factor so as to output a quantized signal.