Configured Grant Cell Switching with Separate UL TCI Selection
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Solution Overview
Problem
Current LTM procedures in wireless communication systems do not adequately consider separate TCI states for downlink and uplink transmissions, leading to inefficiencies in selecting configured grants during cell switch operations, which increases latency and disrupts data transmission.
Innovation Solution
The proposed solution involves a user equipment (UE) that determines the presence or absence of an uplink TCI state ID field in a layer one/layer two triggered mobility (LTM) cell switch command MAC CE, selecting appropriate synchronization signal blocks (SSBs) and configured grants based on TCI states for initial uplink transmissions to a candidate cell, utilizing uplink and joint/downlink TCI state lists for precise grant selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If current LTM procedures use a single TCI state for both downlink and uplink without separate TCI state fields, then the MAC CE structure remains simple, but configured grant selection becomes inefficient and latency increases during cell switch
Solution Approach 1:
The patent segments the TCI state identification into two separate fields: a downlink TCI state ID field and an uplink TCI state ID field. This segmentation allows independent selection of downlink and uplink TCI states, enabling efficient configured grant selection during cell switch while maintaining clear structure in the MAC CE through distinct field definitions.
Solution Approach 2:
The patent adds a new dimension to the TCI state configuration by introducing separate downlink and uplink TCI state fields. This dimensional expansion allows the system to independently control downlink and uplink beam configurations during LTM cell switch, resolving the latency issue without compromising MAC CE manageability through structured field organization.
2Productivity
If separate TCI states for downlink and uplink are introduced with two TCI state fields in MAC CE, then configured grant selection efficiency improves, but MAC CE complexity increases
Solution Approach 1:
By segmenting TCI state identification into separate downlink and uplink fields, the patent enables efficient configured grant selection through independent uplink TCI state referencing. The MAC CE structure manages this complexity through well-defined field boundaries and clear interpretation rules for each TCI state field.
Solution Approach 2:
The patent applies local quality by allowing different TCI state configurations for downlink and uplink based on specific network conditions and cell switch requirements. Each TCI state field can be independently configured and interpreted, enabling optimized grant selection efficiency for specific uplink transmissions while maintaining overall MAC CE structure through standardized field definitions.
3Reliability
If no separate uplink TCI state field is provided in LTM cell switch command, then MAC CE remains simple, but UE cannot properly select configured grant for initial uplink transmission
Solution Approach 1:
The patent introduces segmentation by adding a dedicated uplink TCI state ID field separate from the downlink TCI state field. This enables the UE to reliably select the appropriate configured grant for initial uplink transmission by referencing the specific uplink TCI state, while the MAC CE maintains structure through defined field organization and interpretation protocols.
Data Source
AI summary
A user equipment (UE) capable of facilitating communications in a wireless system can include a transceiver and a processor. In some examples, the transceiver is to receive, from a base station (BS), an LTM cell switch command MAC CE for performing a LTM cell switch. If a presence of a UL TCI state ID field is determined, selecting a SSB associated with a TCI state indicated by a UL TCI state ID field and selecting a configured grant associated with the selected SSB for an initial uplink transmission towards a candidate cell. If the absence of the UL TCI state ID field is determined, selecting a SSB associated with a TCI state indicated by a TCI state ID field of the LTM cell switch command MAC CE and selecting a configured grant associated with the selected SSB for the initial uplink transmission towards the candidate cell.