QC-LDPC Base Graph Selection from Control Information
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Solution Overview
Problem
In wireless communication systems, especially in New Radio (NR) communication, the use of quasi-cyclic Low Density Parity Check (QC-LDPC) codes for encoding and decoding information bits can lead to errors when the transmitter and receiver do not use the same base graph due to channel distortion or delay, resulting in incorrect decoding of information bits.
Innovation Solution
The method involves determining a redundancy version and a new data indicator through control information to select the appropriate base graph for encoding and decoding QC-LDPC codes, ensuring consistency between the transmitter and receiver by using downlink control information to accurately choose between predefined base graphs based on specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver uses a wrong base graph due to channel distortion or delay, then decoding errors occur, but using multiple predefined base graphs increases system complexity
Solution Approach 1:
The transmitter determines the base graph index before encoding the information bits and includes it in the control information transmitted to the receiver. This preliminary action ensures that the receiver can retrieve and use the correct base graph index without needing to independently determine it, thereby preventing decoding errors while avoiding the complexity of multiple base graph determination mechanisms at the receiver side
Solution Approach 2:
The control information acts as an intermediary carrier that transmits the base graph index from the transmitter to the receiver. This intermediary mechanism allows the receiver to obtain the correct base graph index without direct complex interaction or independent determination, resolving the contradiction between reliable decoding and system complexity
2Reliability
If the transmitter and receiver use different base graphs, then data integrity deteriorates, but ensuring base graph consistency requires additional control signaling
Solution Approach 1:
The base graph index is merged with other control information (such as new data indicator and redundancy version) into a unified control information structure. This merging approach allows the transmission of the base graph index without requiring separate dedicated signaling resources, thereby ensuring data integrity through consistent base graph selection while minimizing additional control information overhead
3Measurement precision
If channel distortion occurs causing missed information bits, then the receiver cannot accurately determine the base graph, but retransmitting increases transmission time
Solution Approach 1:
The base graph index is determined and transmitted in advance as part of the control information before the actual data transmission. This preliminary action ensures that even if channel distortion causes missed information bits, the receiver can still accurately determine the base graph from the control information without needing retransmission, thereby maintaining measurement precision while avoiding transmission delays
Data Source
AI summary
A system and method for allocating network resources are disclosed herein. In one embodiment, the system and method are configured to perform: determining a redundancy version and a new data indicator indicated by control information; determining a base graph of a low density parity check code based on which of a plurality of predefined conditions the redundancy version, and/or the new data indicator satisfy; and sending a signal comprising information bits that are encoded based on the determined base graph of the low density parity check code.