DCI Beam Indication with ACK-Synced CORESET Switching
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Solution Overview
Problem
Existing wireless communication systems face challenges in reducing latency and overhead of beam switching while maintaining beam indication reliability, particularly in MIMO systems where the number of TCI states and available beams is limited.
Innovation Solution
The method involves indicating a beam or TCI state in downlink control information (DCI) and switching the beam after an acknowledgment of the scheduled transmission, allowing both the base station and the UE to synchronize beam changes, with a time offset for potential retransmissions if the acknowledgment is not received correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If beam switching is performed quickly without acknowledgment confirmation, then latency is reduced, but beam indication reliability deteriorates
Solution Approach 1:
The patent includes TCI indication in the DCI message in advance, so the UE can prepare for beam switching before it is actually needed. The beam switching is triggered by an acknowledgment (ACK) from the UE, which confirms successful DCI reception. This preliminary preparation with advance notification allows the system to switch beams quickly once confirmed, while maintaining reliability through the ACK mechanism.
Solution Approach 2:
The patent uses acknowledgment (ACK) feedback from the UE to confirm successful reception of the DCI containing TCI indication. This feedback mechanism ensures that the base station only switches the control beam when the UE has correctly received the beam switching instruction, thereby maintaining beam indication reliability while enabling fast beam switching.
2Loss of time
If beam switching is performed without synchronization between base station and UE, then latency is reduced, but communication reliability deteriorates
Solution Approach 1:
The patent employs ACK feedback from the UE to confirm successful reception of the DCI with TCI indication. This feedback enables synchronized beam switching between the base station and UE, as both parties switch beams at the same time point (after the ACK is received), ensuring communication reliability while maintaining fast switching.
Solution Approach 2:
The TCI indication is included in the DCI message in advance, allowing the UE to prepare for beam switching before the actual switch occurs. The beam switching is triggered by the ACK, ensuring both base station and UE switch at the same time, achieving synchronization without additional latency.
3Adaptability or versatility
If the number of TCI states is increased to provide more beam options, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent divides the TCI states into two groups: first TCI states for control channels (PDCCH) and second TCI states for data channels (PDSCH/PUSCH). This segmentation allows independent management of control and data beam configurations, reducing overall system complexity while maintaining adaptability. The DCI can indicate TCI from either group depending on the channel type.
Solution Approach 2:
The patent creates a unified TCI state management mechanism where a single DCI message can indicate TCI states for both control and data channels. The TCI indication in DCI serves multiple purposes: indicating control beam for PDCCH and data beam for PDSCH/PUSCH, reducing the need for separate signaling mechanisms and simplifying device complexity.
Data Source
AI summary
A user equipment (UE) and a base station may utilize downlink control information (DCI) based beam indication to switch beams for wireless communications. The base station may transmit and the UE may receive on a control beam for a control resource set (CORESET), a downlink control information (DCI) that includes a transmission configuration indicator (TCI) and schedules a transmission between the UE and the base station. The UE and the base station may communicate the scheduled transmission. The UE and the base station may determine an acknowledgment of the DCI based on the scheduled transmission. The UE and the base station may switch the control beam for the CORESET based on the TCI after a time offset from the acknowledgment.