Adaptive Code Rate Control for LDPC Signal Transmission
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Solution Overview
Problem
In broadcasting communication systems, noise, fading, and Inter-Symbol Interference (ISI) degrade link performance, and existing error-correcting codes like LDPC struggle to maintain consistent Bit Error Rate (BER)/Frame Error Rate (FER) performance across varying information word lengths, necessitating adaptive control of code rate.
Innovation Solution
The method involves determining the number of punctured bits based on Equations (1), (2), (3), and (4) to adjust the code rate, using a transmitter that shortens or punctures codewords, and a receiver that decodes accordingly, ensuring stable performance by adapting parameters A and B to match the signaling type and required FER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of punctured bits is increased to increase code rate, then data transmission efficiency is improved, but BER/EER performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the puncturing pattern adaptive rather than fixed. The puncturing pattern is dynamically adjusted based on the information word length to maintain consistent BER/EER performance across different code rates. This allows the system to optimize between transmission efficiency and reliability depending on the specific transmission conditions and data length.
Solution Approach 2:
The patent changes the parameter of puncturing pattern based on the information word length. By varying the puncturing pattern according to different data lengths, the system can maintain optimal BER/EER performance while adapting the code rate to match the transmission requirements, thus resolving the contradiction between transmission efficiency and reliability.
2Reliability
If the number of shortened bits is increased to decrease code rate, then BER/EER performance is improved, but data transmission efficiency deteriorates
Solution Approach 1:
The patent makes the shortening operation dynamic by adapting the number of shortened bits based on the information word length. This dynamic adjustment allows the system to achieve better BER/EER performance when needed while avoiding unnecessary shortening that would reduce transmission efficiency, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent changes the shortening parameter adaptively based on the information word length. By adjusting the shortening operation according to specific transmission conditions, the system can optimize the balance between improving BER/EER performance and maintaining data transmission efficiency.
3Device complexity
If fixed puncturing and shortening patterns are used, then system complexity is reduced, but performance consistency across different information word lengths deteriorates
Solution Approach 1:
The patent changes the puncturing and shortening parameters based on the information word length. By adapting these parameters to match different data lengths, the system maintains consistent BER/EER performance across various transmission scenarios without requiring overly complex adaptive mechanisms.
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
An apparatus and a method for transmitting and receiving a signal in a communication system are provided. The method includes checking a type of the signal to be transmitted;; determining a number of puncture bits according to the type of the signal; and puncturing an encoded signal to be transmitted according to the number of puncture bits.