Aperiodic CSI-RS Triggering with Mixed-Numerology Slot Mapping
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Solution Overview
Problem
The current aperiodic CSI-RS triggering procedure in NR is not well-defined for cases where DCI and CSI-RS are transmitted on carriers with different numerologies, leading to ambiguity in slot determination and increased UE implementation complexity and memory consumption.
Innovation Solution
A predefined rule is introduced to map the PDCCH reception slot in the numerology of the triggering PDCCH to a reference slot in the numerology of the CSI-RS, ensuring seamless aperiodic CSI-RS triggering by determining the slot of the CSI-RS based on this reference slot and the aperiodic CSI-RS slot offset, minimizing UE memory consumption and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If aperiodic CSI-RS triggering is implemented with mixed numerologies on different carriers, then network flexibility and adaptability are improved, but slot determination ambiguity and UE implementation complexity increase
Solution Approach 1:
The patent introduces an intermediary reference slot concept that mediates between the PDCCH carrier and CSI-RS carrier with different numerologies. The reference slot serves as a common time reference point that both carriers can use to determine CSI-RS timing, eliminating the need for complex cross-numerology slot calculations at the UE and resolving the slot determination ambiguity.
2Adaptability or versatility
If aperiodic CSI-RS triggering is implemented with mixed numerologies on different carriers, then network flexibility and adaptability are improved, but memory consumption increases
Solution Approach 1:
The patent extracts the timing determination logic from the UE by introducing a predefined rule based on reference slot that is controlled by the network. This removes the need for the UE to buffer and store multiple slot timing configurations for different numerologies, significantly reducing memory consumption while maintaining numerology flexibility.
3Ease of operation
If slot determination is performed without a predefined reference slot mapping rule, then UE autonomy is maintained, but slot determination ambiguity increases
Solution Approach 1:
The patent applies preliminary action by establishing a reference slot mapping rule in advance, before actual CSI-RS triggering occurs. This predefined rule eliminates slot determination ambiguity by providing a clear, deterministic method for mapping PDCCH slots to CSI-RS slots across different numerologies, while still allowing UE autonomy in following the standardized procedure.
Data Source
AI summary
Devices, systems, and methods described herein may improve aperiodic CSI-RS handling in mixed numerology environments. An exemplary method includes operations of receiving a downlink control information (DCI) message carried by a Physical Downlink Control Channel (PDCCH) on a second carrier, wherein the second carrier uses a second OFDM numerology, obtaining an aperiodic CSI-RS slot offset from the DCI message, determining a reference slot in the first numerology, determining the slot of the aperiodic CSI-RS based on the reference slot and the aperiodic CSI-RS slot offset, and receiving or transmitting the aperiodic CSI-RS in the determined slot.