Unified Beam Indication for UL-DL Alignment in 5G UEs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies face challenges in controlling the direction of uplink signals from user equipment (UE) to align with the desired receive beamforming direction at the gNB, particularly in cases where UE lacks beam correspondence capability or lacks effective DL beam management based on UL RS such as SRS.
Innovation Solution
A unified DL and UL beam indication framework is introduced, where the gNB signals a TCI state to the UE for adjusting its beamforming weights, using both DL and UL RSs to ensure alignment with desired gNB Rx beam directions, and the UE adjusts its Tx beamforming weights based on associated RSs to align with Rx beamforming weights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gNB signals a TCI state to the UE for beam indication, then the beam alignment between UE Tx and gNB Rx is improved, but the signaling overhead increases
Solution Approach 1:
The patent merges DL and UL beam indication into a single TCI state framework. The TCI state includes both DL RS (for downlink beam indication) and UL RS (for uplink beam indication), allowing the UE to determine both receive and transmit beam configurations from one indication mechanism, thereby reducing signaling overhead while maintaining beam alignment reliability
Solution Approach 2:
The TCI state is designed to serve multiple functions simultaneously: it provides spatial QCL reference for PDSCH demodulation, indicates gNB Rx beam direction, and enables UE Tx beamforming weight adjustment. This multi-functional design eliminates the need for separate signaling mechanisms for different beam management tasks
2Reliability
If the UE adjusts its spatial Tx configuration based on DL RS, then the uplink beam alignment is improved, but the complexity of beam management increases
Solution Approach 1:
The patent enables the UE to autonomously determine its transmit beam configuration by utilizing the DL RS spatial information. The UE self-adjusts its Tx beamforming weights based on the TCI state indication without requiring explicit gNB control commands for each beam adjustment, thereby simplifying the overall beam management complexity while maintaining alignment reliability
Solution Approach 2:
The TCI state mechanism provides implicit feedback about the desired beam configuration. By signaling which DL RS and UL RS should be associated with the TCI state, the system enables the UE to infer the appropriate beam directions and adjust its configuration accordingly, creating a feedback loop that simplifies gNB control while ensuring accurate beam alignment
3Adaptability or versatility
If the system supports both beam correspondence and non-beam correspondence UEs, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The TCI state framework is designed to be universally applicable to both beam correspondence and non-beam correspondence UEs. The same indication mechanism works for both types of UEs, with the UE autonomously determining whether to use beam correspondence assumptions or direct UL RS-based configuration based on its capabilities, thereby achieving adaptability without increasing system complexity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A user equipment (UE) the UE being configured to receive a message comprising configuration information, CI, indicating that a reference signal, RS, is quasi-co-located, QCL, with a transmission; and adjust a spatial Tx configuration for the transmission based on an RS associated with the received CI.