Adaptive CRC Bit Selection for LDPC Throughput Balance

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Solution Overview

Problem

The combination of low-density parity-check (LDPC) codes with high numbers of cyclic redundancy check (CRC) bits in communication systems leads to unnecessary bit transmission and reduced throughput.

Innovation Solution

A system and method for selecting the number of CRC bits based on the information block length (K) and/or code rate (R) in a communication system, using tables and simulations to determine optimal CRC bit allocation for each combination of K and R, thereby reducing unnecessary bit transmission while maintaining error detection capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high numbers of CRC bits are used with LDPC codes, then error detection capability is improved, but transmission throughput is reduced due to unnecessary bit transmission

Engineering Contradiction:

Improveerror detection capabilityVSAvoidtransmission throughput

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the number of CRC bits based on the code rate and information block length. Different combinations of code rate (R) and information block length (K) map to different optimal CRC bit lengths, allowing the system to adapt the error detection capability to match the actual transmission conditions and avoid unnecessary bit transmission

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the CRC bit length a variable parameter rather than a fixed value. The system dynamically selects the appropriate CRC bit length according to the scheduled code rate and information block length, enabling flexible adaptation to varying transmission requirements and optimizing the balance between error detection and throughput

Inventive Principle:

Principle #15Dynamics

2Reliability

If high numbers of CRC bits are transmitted, then error detection capability is improved, but unnecessary bits are transmitted

Engineering Contradiction:

Improveerror detection capabilityVSAvoidunnecessary bit transmission

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the parameter of CRC bit length based on specific transmission conditions (code rate and information block length). By mapping different R-K combinations to optimal CRC lengths, the system transmits only the necessary number of CRC bits required for adequate error detection, eliminating unnecessary bit transmission

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12476734B2Cyclic redundancy check selection

Publication Date: 2025.11.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A system and method for selecting a number of cyclic redundancy check bits in a communication system. In one embodiment, an apparatus operating in a communication system is configured to receive scheduling information from the communication system, and determine an information block length (K) and/or code rate (R) for a code block including a sequence of data bits from the scheduling information. The apparatus is further configured to determine a number of cyclic redundancy check (CRC) bits as a function of the information block length (K) and/or code rate (R) for the code block.