TCI State Switching in Multi-TRP PRACH Transmissions
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Solution Overview
Problem
In multi-transmission reception point scenarios, existing mobile communication systems face challenges in efficiently managing and prioritizing physical downlink control channel (PDCCH) ordered physical random access channel (PRACH) transmissions, particularly in coordinating transmission configuration indicator states with different timing advance group identifiers, which affects the timing and prioritization of uplink transmissions.
Innovation Solution
A method and apparatus that determine and apply different transmission configuration indicator states associated with distinct timing advance group identifiers, allowing for the prioritization and scheduling of uplink transmissions based on timing advance values, enabling the UE to switch between TCI states and adjust beam application times to optimize PRACH transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple TCI states with different TAG identifiers are applied in adjacent slots, then the adaptability and versatility of transmission configuration are improved, but the device complexity and difficulty of managing PRACH transmissions increase
Solution Approach 1:
The patent establishes predetermined rules for determining the third slot where TCI state switching occurs. These rules consider factors such as whether the second slot is an uplink slot and whether uplink transmissions are scheduled, allowing the UE to automatically determine the correct switching timing without complex real-time decisions, thereby reducing management complexity while maintaining configuration adaptability
Solution Approach 2:
The patent segments the TCI state application process into distinct cases based on slot types and transmission schedules. By dividing the problem into manageable scenarios (uplink slots vs. downlink slots, scheduled vs. unscheduled transmissions), the system handles complex multi-TAG configurations through structured case analysis rather than monolithic complexity
2Reliability
If TCI state switching is performed in adjacent slots with different timing advance values, then the reliability of uplink transmissions is improved, but the timing coordination and synchronization difficulty increase
Solution Approach 1:
The patent performs preliminary assessment of slot characteristics and transmission schedules before determining TCI state switching timing. By evaluating whether slots are uplink or downlink and checking for scheduled transmissions in advance, the system prevents timing conflicts and ensures reliable switching without requiring complex real-time timing measurements
Solution Approach 2:
The patent introduces the concept of a third slot as an intermediary between the first and second slots where TCI states are initially intended to be applied. This intermediary slot provides a buffer that facilitates smooth timing advance transitions between different TAGs, reducing timing coordination difficulty while maintaining transmission reliability
3Productivity
If the second TCI state is applied immediately in the second slot, then the productivity and speed of configuration application are improved, but the timing advance synchronization and transmission reliability may deteriorate
Solution Approach 1:
The patent performs preliminary checks on slot characteristics and transmission schedules before determining when to apply the second TCI state. By assessing uplink/downlink slot types and scheduled transmissions in advance, the system identifies the optimal third slot for switching that maintains both fast configuration application and proper timing advance synchronization
Solution Approach 2:
The patent makes the TCI state application timing dynamic rather than fixed. The third slot where the second TCI state is applied is determined based on real-time conditions including slot type and transmission schedule, allowing the system to adapt the switching timing to maintain synchronization reliability while achieving fast configuration updates
Data Source
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AI summary
Systems, methods, apparatuses, and computer program products for facilitating triggered PDCCH-ordered PRACH transmissions in multi-TRP scenarios. One method may include a UE determining that a first TCI state is to be applied in a first slot and a second TCI state is to be applied in a second slot. The first TCI state is associated with a first TAG ID, a second TCI state is associated with a second TAG ID different than the first TAG ID, and the second slot is succeeding and adjacent to the first slot. The method may further include, based upon the determining, determining a third slot. The second TCI state is firstly to be applied in the third slot. The method may further include applying the second TCI state from the third slot onward.