DMRS Positioning Ambiguity in NR Resource Indication
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Solution Overview
Problem
Current designs for mapping type A in new radio (NR) communications systems face errors in indicating the correct time domain position of additional demodulation reference signals (DMRS) due to ambiguity in PUSCH or PDSCH duration, affecting communication between network devices and terminal devices.
Innovation Solution
A resource indication method is provided, where a terminal device receives first indication information from a network device to determine the mapping type of a physical shared channel, and then uses this information to accurately determine the time domain positions of DMRSs based on the mapping type and either the position index of the last symbol occupied by the physical shared channel or the quantity of symbols occupied by the physical shared channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same PDSCH duration is used for both mapping type A and mapping type B, then the resource indication is simplified, but the terminal device cannot accurately determine the time domain position of additional DMRS
Solution Approach 1:
The patent segments the resource indication by introducing a mapping type indication field that separates mapping type A and mapping type B into distinct categories. This allows each mapping type to have its own specific indication rules and parameters, enabling accurate DMRS position determination while maintaining overall system simplicity through structured segmentation of the indication mechanism
Solution Approach 2:
The patent applies local quality by providing mapping type-specific indication information tailored to each mapping type's requirements. For mapping type A, the indication uses PDSCH duration, while for mapping type B, it uses start symbol and duration. This localized customization ensures accurate DMRS position determination for each mapping type without requiring a completely different indication system for both types
2Adaptability or versatility
If the network device uses PDSCH duration to indicate additional DMRS position, then the indication method is unified, but ambiguity occurs when PDSCH duration is the same for both mapping types
Solution Approach 1:
The patent applies preliminary action by having the network device indicate the mapping type in advance through a mapping type indication field before providing the duration information. This preliminary classification allows the terminal device to interpret the subsequent duration information correctly according to the specific mapping type, preventing ambiguity while maintaining unified indication structure
Solution Approach 2:
The mapping type indication field serves as an intermediary element between the unified indication structure and the mapping-type-specific parameters. It mediates the information flow by first establishing which mapping type is being used, then allowing the duration or position information to be interpreted correctly based on that intermediary classification
Data Source
AI summary
This application provides a resource indication method, a terminal device, and a network device. The method includes: receiving, by the terminal device, the first indication information, and determining time domain positions of demodulation reference signals (DMRSs) based on the mapping type of the physical shared channel and with reference to a position index of the last symbol occupied by the physical shared channel or a quantity of symbols occupied by the physical shared channel in the resource unit, where the position index of the last symbol occupied by the physical shared channel in the resource unit corresponds to the first type, and the quantity of symbols occupied by the physical shared channel in the resource unit corresponds to the second type.