UE TCI State Selection for Multi-TRP Beam Ambiguity
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Solution Overview
Problem
In wireless communications, the ambiguity in determining default transmit beams for user equipment (UE) due to varying beam switching timing thresholds across different transmission schemes and scheduling methods complicates efficient signal transmission between UEs and transmission reception points (TRPs).
Innovation Solution
The implementation of a method where UEs prioritize transmission schemes based on quasi-co-located (QCL) rules to select appropriate transmission configuration indication (TCI) states, allowing them to determine and indicate preferred transmission schemes for default beams, thereby resolving beam ambiguity by using QCL assumptions for single-TRP or multi-TRP schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If beam switching timing threshold changes depending on transmission scheme, then system adaptability improves, but beam determination ambiguity increases
Solution Approach 1:
The patent applies preliminary action by having the UE indicate its preferred transmission scheme to the TRP in advance. This allows the TRP to determine the beam switching timing threshold based on the pre-indicated scheme, resolving the ambiguity of which threshold to apply before actual beam switching occurs. The UE's indication of preferred scheme (single-TRP or multi-TRP) enables the system to pre-establish the appropriate timing threshold and default QCL rules.
Solution Approach 2:
The patent implements feedback through the UE's indication of its preferred transmission scheme to the TRP. This feedback mechanism allows the TRP to adapt its beam switching behavior and threshold selection based on the UE's capabilities and preferences. The TRP uses this feedback information to determine the appropriate beam switching timing threshold and default QCL assumptions, eliminating the ambiguity that would exist without such feedback.
2Adaptability or versatility
If multiple transmission schemes are supported, then system versatility improves, but complexity of beam selection increases
Solution Approach 1:
The patent reduces complexity through preliminary action by having the UE indicate its preferred transmission scheme in advance. This pre-indication allows both the UE and TRP to determine the appropriate beam selection rules and timing thresholds before actual transmission occurs, avoiding the need to evaluate multiple schemes at the moment of beam switching.
Solution Approach 2:
The patent applies local quality by enabling different beam selection behaviors for different transmission schemes. The UE and TRP can apply specific default QCL rules and timing thresholds appropriate to each scheme (single-TRP or multi-TRP) based on the indicated preference, rather than using a single complex set of rules for all scenarios.
3Loss of time
If default QCL rules are used for beam selection, then beam determination speed improves, but transmission reliability may decrease
Solution Approach 1:
The patent resolves the contradiction between speed and reliability through preliminary action. The UE indicates its preferred transmission scheme in advance, allowing the default QCL rules and beam switching timing threshold to be determined beforehand. This pre-determination maintains the speed advantage of using default rules while improving reliability by ensuring the correct scheme-specific rules are applied from the start.
Solution Approach 2:
The feedback mechanism of UE preference indication ensures that the appropriate default QCL rules are selected based on the actual transmission scheme preference. This feedback-driven selection maintains beam determination speed by using default rules while improving reliability by matching the rules to the correct transmission scenario.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may prioritize a transmission scheme for a transmission configuration indication (TCI) state for receiving a downlink message from one or more transmission reception points (TRPs). The UE may receive a downlink control message via a first carrier that schedules a downlink signal for the UE via a second carrier. The UE may select one or more TCI states for reception of the downlink signal based at least in part on the prioritization of the first transmission scheme. The UE may receive the downlink signal via the second carrier in accordance with the selected one or more TCI states.