PUSCH Beam Selection Using TCI States for Flexible Uplink Alignment
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Solution Overview
Problem
In 5G wireless systems, especially in high frequency bands like mmWave, the limited number of transmission and reception units (TXRUs) in network and terminal devices necessitates efficient beam alignment for optimal communication, which is challenging due to hardware limitations and cost constraints, particularly in scenarios where beam directions need to change with device movement.
Innovation Solution
A method and device for physical uplink shared channel (PUSCH) transmission that utilizes transmission configuration indication (TCI) states to dynamically adjust transmission beams, allowing flexible beam selection through DCI, MAC CE, and RRC parameters, enabling efficient beam switching and power control for both codebook and non-codebook based transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of TXRUs are used due to hardware limitations and cost, then device complexity and cost are reduced, but beam alignment flexibility and communication quality deteriorate
Solution Approach 1:
The patent implements dynamic beam switching mechanisms where the network device can switch between different transmit beams based on terminal device movement and channel conditions. The system maintains multiple beam configurations and dynamically selects the optimal beam, enabling adaptability with limited hardware resources.
Solution Approach 2:
The system changes beam parameters (beam direction, beam width) dynamically through beam switching rather than changing hardware configuration. By modifying beamforming parameters software-controlled, the system achieves multiple beam patterns from a fixed limited number of TXRUs, resolving the contradiction between hardware limitations and beam flexibility.
2Reliability
If beam directions are changed to track device movement, then communication quality is maintained, but beam switching complexity and signaling overhead increase
Solution Approach 1:
The patent implements feedback mechanisms where the network device receives beam measurement reports from terminal devices and uses this feedback to determine optimal beam switching decisions. This feedback-driven approach maintains communication quality by adapting to channel conditions while avoiding unnecessary beam switches that would increase complexity.
Solution Approach 2:
The system pre-configures multiple beam options and beam switching strategies in advance. When device movement is detected or predicted, the pre-prepared beam configurations can be quickly activated without complex real-time calculations, reducing beam switching complexity while maintaining communication quality.
3Reliability
If frequent beam switching is performed to track device movement, then link quality is maintained, but power consumption and processing overhead increase
Solution Approach 1:
The patent implements periodic beam switching based on predetermined criteria such as time intervals, distance thresholds, or signal quality thresholds. Instead of continuous beam switching, the system performs beam switching periodically when specific conditions are met, maintaining link quality while reducing unnecessary power consumption from frequent switching operations.
4Measurement precision
If higher layer signaling is used to change Tx beam configuration of SRS resources, then beam configuration accuracy is improved, but signaling overhead and latency increase
Solution Approach 1:
The patent segments beam configuration into different layers: semi-static beam configurations are set through higher layer signaling (RRC/MAC CE) for accuracy, while dynamic beam selection within those configurations is handled through faster physical layer signaling (DCI). This segmentation reduces overall latency while maintaining configuration accuracy where needed.
Data Source
AI summary
A method for transmitting on a physical uplink shared channel, PUSCH is provided. The method comprising: receiving, by a terminal device, configuration information including M transmission configuration indication, TCI, states; receiving, by the terminal device, an activation command to activate K of the M TCI states; receiving, by the terminal device, downlink control information, DCI, to schedule a PUSCH transmission, the DCI indicating a selected TCI state from among the K TCI states; determining, by the terminal device, a spatial domain transmission filter using the selected TCI state; and transmitting, by the terminal device, on the PUSCH according to the determined spatial domain transmission filter.