LLR Quantization in Wireless Reception for Lower Processing Delay
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Solution Overview
Problem
The existing wireless communication systems experience processing delays due to the need to collect sufficient samples of LLR values before determining their statistical distribution for quantization in the SPP scheme.
Innovation Solution
Calculating the variance of the LLR values based on channel information and noise power, allowing for the determination of statistical distribution without sample collection, enabling immediate quantization and reducing processing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sufficient samples of LLR values are collected to determine statistical distribution for quantization, then quantization accuracy is improved, but processing delay increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the statistical distribution characteristics (mean and variance) of LLR values for different modulation schemes before actual quantization processing. This allows the system to immediately determine quantization parameters without waiting to collect sufficient samples during runtime, thus resolving the contradiction between quantization accuracy and processing delay.
2Quantity of substance
If the number of quantization bits for LLR values is reduced, then transmission amount between RRH and BBU is reduced, but quantization error increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting quantization parameters (number of bits, threshold values) based on the statistical distribution characteristics of LLR values. By using pre-calculated mean and variance for different modulation schemes, the system optimizes the balance between transmission amount and quantization error, achieving efficient compression while maintaining acceptable precision.
Data Source
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AI summary
A wireless communication system includes an RF reception unit configured to receive a radio signal from a terminal; a channel estimation unit configured to estimate channel information of a wireless transmission path with respect to the terminal on the basis of the radio signal received by the RF reception unit; a demodulation unit configured to perform soft decision demodulation on the radio signal on the basis of the channel information estimated by the channel estimation unit; a quantization unit configured to quantize a log likelihood ratio obtained through soft decision demodulation in the demodulation unit, on the basis of a statistical distribution determined using an average value of the log likelihood ratio determined in accordance with a modulation scheme used in wireless communication with the terminal and a variance of a log likelihood ratio obtained on the basis of the channel information; and a decoding unit configured to perform a decoding process on the log likelihood ratio quantized by the quantization unit.