QCL Assumption Mapping for Multi-TRP 5G Downlink
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Solution Overview
Problem
Current 5G wireless communication systems with multiple transmission reception points (TRPs) face challenges in efficiently configuring quasi co-located (QCL) assumptions for downlink transmissions, particularly in associating multiple transmission configuration indication (TCI) states with codepoints to optimize beamforming and throughput in multi-TRP and multi-panel scenarios.
Innovation Solution
The method involves transmitting configuration information of multiple TCI states from a base station to user equipment (UE), where activation commands associate subsets of TCI states with codepoints in a TCI field, allowing for determination of QCL assumptions for demodulation reference signal (DMRS) port groups, enabling efficient downlink transmission based on these assumptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple TCI states are configured for multi-TRP operation, then downlink transmission reliability is improved, but configuration complexity increases
Solution Approach 1:
The patent segments the TCI state configuration process into distinct phases: RRC configuration of multiple TCI states, MAC-CE activation commands that associate subsets of TCI states with codepoints, and DCI scheduling that applies specific codepoints. This segmentation allows the system to manage multiple TCI states systematically, improving reliability through diverse TRP configurations while maintaining operational complexity through structured procedures.
Solution Approach 2:
The patent implements preliminary action by pre-configuring multiple TCI states via RRC signaling before actual downlink transmissions. The MAC-CE activation commands further prepare the system by pre-associating TCI state subsets with codepoints. This preliminary configuration enables rapid switching between TRPs during data transmission without real-time configuration overhead, thereby improving reliability while managing complexity.
2Adaptability or versatility
If multiple TCI states are associated with codepoints, then beamforming flexibility is improved, but processing overhead increases
Solution Approach 1:
The patent introduces a codepoint dimension that maps to multiple TCI states. Instead of directly managing multiple TCI state associations, the system uses codepoints as an intermediate layer that can represent different TCI state combinations. This dimensional approach enables flexible beamforming for multi-TRP operation while reducing processing overhead by consolidating multiple associations into single codepoint indicators in DCI.
Solution Approach 2:
The patent uses codepoints as intermediaries between the MAC-CE activation commands and the DCI scheduling decisions. The MAC-CE commands pre-establish the mapping between codepoints and TCI state subsets, creating an intermediary layer that simplifies real-time scheduling. This intermediary mechanism provides beamforming flexibility without requiring complex real-time processing of multiple TCI state associations.
3Productivity
If QCL assumptions are determined for multiple DMRS port groups, then throughput is improved, but signal processing complexity increases
Solution Approach 1:
The patent segments the DMRS port groups and applies different QCL assumptions to different segments. Each DMRS port group can be associated with specific TCI states through codepoints, allowing independent optimization of different spatial layers. This segmentation enables parallel processing of multiple DMRS port groups with different QCL assumptions, improving throughput while managing signal processing complexity through modular handling of each port group.
Solution Approach 2:
The patent applies local quality by determining specific QCL assumptions for each DMRS port group based on the corresponding TCI state and codepoint associations. Rather than applying a uniform QCL assumption across all ports, the system optimizes each port group's QCL properties according to its specific TRP and beam configuration. This localized optimization improves overall throughput while keeping processing complexity manageable through structured per-port-group handling.
Data Source
AI summary
Aspects of the disclosure provide a user equipment (UE). The UE receives configuration information of multiple transmission configuration indication (TCI) states. The UE receives one or more activation commands that associate a first subset of the TCI states with one or more codepoints of a TCI field and a second subset of the TCI states with the one or more codepoints of the TCI field. The UE receives a codepoint associated with a first TCI state in the first subset of the TCI states and a second TCI state in the second subset of the TCI states. The UE determines at least one first quasi co-located (QCL) assumption according to the first TCI state and at least one second QCL assumption according to the second TCI state. The UE receives a downlink transmission based on the at least one first QCL assumption and the at least one second QCL assumption.