UE Multi-TRP PDSCH Overlap Handling via Capability Reporting
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Solution Overview
Problem
In 5G NR networks, the UE faces challenges in handling overlapping PDSCHs, particularly in frequency domain overlap, which causes interference, and in cross-carrier PDSCH scheduling, where the UE may not have enough time to switch beams or requires buffering all component carriers. Additionally, in dynamic spectrum sharing environments, interference can occur between 5G NR and LTE signals due to collisions between DMRS and CRS.
Innovation Solution
The UE groups its capabilities regarding overlapping PDSCHs into multiple groups and reports these capabilities to the gNB, allowing the network to schedule PDSCHs accordingly. The UE determines a default beam for receiving PDSCHs when the TCI field is not configured, and shifts the DMRS in scenarios where collisions with LTE signals are expected to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE receives multiple overlapping PDSCHs from multiple TRPs to improve throughput, then the data transmission rate increases, but interference between overlapping signals causes degradation in reception quality
Solution Approach 1:
The UE segments the received PDSCH signals by identifying separate TCI states for different TRPs, allowing the UE to separately process and decode overlapping PDSCHs from different transmission points by associating each with its own beam configuration
Solution Approach 2:
The patent applies local quality by configuring different TCI states with specific QCL relationships for different spatial locations/TRPs, allowing the UE to apply appropriate beamforming and reception parameters locally for each TRP's signal even when signals overlap in time and frequency
2Productivity
If the gNB schedules PDSCH with a short time offset to increase scheduling flexibility, then resource utilization improves, but the UE does not have enough time to switch beams causing reception failures
Solution Approach 1:
The gNB performs preliminary action by pre-configuring multiple TCI states and their associated QCL relationships before PDSCH transmission, allowing the UE to have beam switching information ready in advance, thus enabling rapid beam switching when the scheduled time offset is short
Solution Approach 2:
The patent implements dynamics by allowing the TCI field in DCI to dynamically indicate which pre-configured TCI state to use for the scheduled PDSCH, enabling the UE to quickly switch between different beam configurations based on the dynamic scheduling decision without requiring lengthy reconfiguration
3Device complexity
If the UE uses the lowest TCI codepoint as default beam to simplify beam selection, then the complexity of beam management is reduced, but the UE may not select the optimal beam for PDSCH reception
Solution Approach 1:
The patent applies dynamics by making the beam selection adaptive through the TCI field in DCI, which can dynamically indicate the appropriate TCI codepoint based on current channel conditions and TRP configurations, allowing the system to move from a static lowest-codepoint rule to a dynamic optimal-beam-selection mechanism
4Productivity
If 5G NR and LTE transmissions share the same spectrum to maximize spectrum utilization, then spectral efficiency increases, but interference between DMRS and CRS signals degrades communication reliability
Solution Approach 1:
The patent introduces an intermediary mechanism through rate matching configurations that allow the 5G NR PDSCH to be scheduled around LTE CRS resources, and through TCI state configurations that help the UE identify and handle interference from overlapping signals by associating them with appropriate QCL relationships
Data Source
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AI summary
An apparatus comprising processing circuitry configured to determine a user equipment (UE) supports multiple Downlink Control Information (multi-DCI) based multiple transmission and reception point (multi-TRP) operation with a network, determine a capability of the UE in multi-DCI multi-TRP operation related to overlapping physical downlink shared channel (PDSCH) transmissions from the network; and generate, for transmission to the network, an information element (IE) indicating the capability of the UE related to the overlapping PDSCH transmissions.