TCI State Signaling for Accurate Multi-TRP Beam Indication
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Solution Overview
Problem
The NR Rel-17 protocol only supports single transmission reception point (sTRP) scenarios, and beam indication signaling based on DCI format 1_1/1_2 is inadequate for multi-transmission reception point (mTRP) scenarios, leading to mismatches in TCI state indications and increased complexity in handover scenarios.
Innovation Solution
A method and apparatus for beam indication that includes acquiring transmission capability information of a terminal, sending a message with TCI state information, and dynamically switching between single and multi-TRP transmission modes, using TCI mode and TRP indication fields to ensure accurate TRP transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DCI format 1_1/1_2 beam indication signaling is used for both data scheduling and beam indication in Rel-17, then the signaling can be simplified, but the indicated beam cannot be used for the scheduled PDSCH causing mismatch in TCI state indications
Solution Approach 1:
The patent segments the beam indication function by introducing a separate MAC-CE signaling mechanism specifically for TCI state activation, distinct from the DCI format 1_1/1_2 scheduling signaling. This segmentation allows the scheduling DCI to reference pre-activated TCI states without causing mismatch, as the TCI states are activated in advance through the separate MAC-CE procedure.
Solution Approach 2:
The patent applies preliminary action by requiring the network to activate TCI states through MAC-CE signaling before the actual PDSCH transmission. The TCI states must be activated in advance, and the scheduling DCI then references these pre-activated states. This preliminary activation ensures that the beam indication is ready before scheduling, resolving the mismatch problem.
2Device complexity
If Rel-17 single TRP protocol is used, then the protocol is simpler, but it cannot support multi-TRP handover scenarios
Solution Approach 1:
The patent achieves universality by designing a unified TCI state activation mechanism that works for both single TRP and multi-TRP scenarios. The MAC-CE signaling for TCI activation and the subsequent DCI referencing mechanism are designed to be compatible with both Rel-17 sTRP and Rel-18 mTRP modes, allowing the same framework to support multiple TRP scenarios without requiring separate protocol implementations.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the system to switch between single TRP and multi-TRP modes based on actual transmission needs. The network can dynamically activate multiple TCI states through MAC-CE signaling when mTRP is required, and the scheduling DCI can reference these states accordingly. This dynamic configuration enables the system to adapt to different TRP scenarios without protocol changes.
3Productivity
If multiple TCI states are indicated for mTRP scenario, then transmission diversity is improved, but the number of indicated TCI states does not match the scheduled PDSCH
Solution Approach 1:
The patent implements feedback mechanisms where the network provides explicit indication through MAC-CE signaling about which TCI states are activated and their corresponding purposes. The scheduling DCI includes references to these activated TCI states, creating a feedback loop that ensures the indicated TCI states match the scheduled PDSCH requirements. This feedback mechanism prevents information loss about TCI state matching.
Solution Approach 2:
The patent introduces MAC-CE signaling as an intermediary mechanism between the network's TCI state configuration and the scheduling DCI. This intermediary layer explicitly connects the TCI states to the scheduled PDSCH, ensuring that the multiple TCI states indicated for mTRP scenarios are properly matched to the scheduling information. The MAC-CE signaling acts as a mediator that bridges the configuration and scheduling domains.
Data Source
AI summary
The present disclosure provides a beam indication method and apparatus, a device and a storage medium. The method includes acquiring transmission capability information of a terminal device UE; and transmitting a first message to the UE according to the transmission capability information, where the first message includes at least one piece of transmission configuration indication TCI state information, and the first message is indicative of performing transmission by the UE according to the TCI state information. In the present disclosure, a network device can give an indication of a transmission mode to be adopted by a UE to the UE through a first message, that is, adopting sTRP transmission or mTRP transmission, and the network device can accurately instruct the UE to perform different TRP transmission processes according to different TRP scenarios, and can realize dynamic switching between sTRP transmission and mTRP transmission.