PDSCH TCI State Selection for Wireless UE
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for determining directional transmit and receive beams in wireless communications systems, particularly in millimeter wave frequency ranges, are deficient, leading to inefficiencies in beamforming and signal processing due to the increased signal attenuation.
Innovation Solution
The described techniques enable a capability-based determination of a shared data channel transmission configuration indicator (TCI) state, allowing a user equipment (UE) to select a physical downlink shared channel (PDSCH) TCI state based on its capabilities and the number of TCI states supported, using techniques such as media access control (MAC) control elements, specific CORESET TCI states, or radio resource control (RRC) messages to optimize beamforming parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used to overcome path loss in mmW frequency ranges, then signal reception quality is improved, but device complexity increases due to multiple TCI states and beam management requirements
Solution Approach 1:
The patent changes the parameter of TCI state indication by introducing multiple indication methods (MAC CE, DCI, RRC) with different activation timings and granularities. This allows the system to adapt the beam management complexity to match the UE's capability, thereby improving signal reception quality without excessively increasing device complexity for all UEs.
Solution Approach 2:
The patent segments the TCI state management into different layers: MAC CE for semi-persistent activation, DCI for dynamic selection, and RRC for configuration. This segmentation allows each layer to handle specific aspects of beam management, reducing the overall complexity by distributing the management tasks across different protocol layers.
2Adaptability or versatility
If the UE supports multiple activated TCI states for PDSCH, then beamforming flexibility is improved, but the UE capability requirements increase
Solution Approach 1:
The patent introduces dynamic TCI state activation where the UE can be configured with multiple TCI states but only needs to maintain a limited number of activated states at any given time. The activation is dynamically controlled through MAC CE and DCI, allowing the UE to adapt its beamforming flexibility to its current capability while the network can request higher flexibility when needed.
Solution Approach 2:
The patent allows the network to configure more TCI states than the UE needs to simultaneously activate. The UE can select a subset of configured TCI states based on its capability, providing partial activation. This approach gives the system the option to use more states when necessary while allowing UEs with limited capability to operate with fewer activated states.
3Ease of operation
If conventional TCI state determination methods are used, then implementation simplicity is maintained, but communication efficiency decreases in challenging frequency ranges
Solution Approach 1:
The patent introduces MAC CE as an intermediary between RRC configuration and DCI scheduling for TCI state activation. This intermediary layer allows the system to maintain simple DCI-based scheduling while enabling efficient beam management through MAC CE-controlled TCI state activation, thereby improving communication efficiency without significantly complicating the implementation.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A base station and a user equipment (UE) with a defined capability may communicate using beamformed wireless communications. The defined capability may be that the UE may support fewer activated physical downlink shared channel (PDSCH) transmission configuration indicator (TCI) states than activated control resource set (CORESET) TCI states. The defined capability UE and the base station may implement techniques to determine which TCI state to use when the UE supports fewer activated PDSCH TCI states than activated CORESET TCI states. The UE may use an activated PDSCH TCI state selected by a media access control (MAC) control element (CE), an activated TCI state of a specific CORESET, a TCI indicated in scheduling downlink control information, or an activated PDSCH TCI state selected by a radio resource control (RRC) message.