PRACH Timing Advance Updates for Deactivated Cells in Mobility
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing timing advance updates during Layer 1 and Layer 2 mobility, particularly in scenarios involving deactivated cells and multiple transmission reception points (TRPs), leading to inefficiencies and potential interference.
Innovation Solution
Implementing techniques for user equipment (UE) and network nodes to facilitate PRACH-based timing advance (TA) updates for deactivated cells and multi-TRP configurations, including the use of DCI transmissions and TA commands to adjust timing advances based on reference signal reception timings and TRP-specific parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PRACH-based TA update operation is performed for deactivated cells during Layer 1 and Layer 2 mobility, then timing advance management efficiency is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by performing TA update operations for deactivated cells in advance before they are activated. The network node transmits TA commands to the UE for deactivated cells, allowing the UE to have pre-configured timing information ready. This eliminates the need for complex real-time TA acquisition when activation occurs, thereby improving productivity while managing complexity through advance preparation.
Solution Approach 2:
The patent uses TA commands as an intermediary mechanism to transfer timing information from the network node to the UE for deactivated cells. Instead of requiring direct PRACH-based TA acquisition during activation, the TA command acts as a mediator that carries timing advance information, simplifying the overall process and reducing the complexity burden on the UE while maintaining efficient TA management.
2Measurement precision
If TA commands are transmitted for deactivated cells, then timing synchronization accuracy is improved, but loss of time for processing increases
Solution Approach 1:
The patent applies preliminary action by transmitting TA commands for deactivated cells before activation is needed. The network node proactively provides timing information, allowing the UE to process and store TA parameters in advance. This approach ensures high timing synchronization accuracy when activation occurs while minimizing real-time processing delays, as the critical TA information is already prepared and available.
3Reliability
If PRACH message transmission is performed for deactivated cells, then reliability of TA update is improved, but use of energy increases
Solution Approach 1:
The patent applies preliminary action by establishing TA information for deactivated cells before activation is required. The network node transmits TA commands that include all necessary timing parameters in advance, allowing the UE to configure timing without requiring subsequent PRACH-based TA acquisition. This preliminary configuration ensures reliable TA updates while avoiding the energy-intensive PRACH transmissions that would be needed if TA information were acquired at activation time.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a downlink control information (DCI) transmission comprising a physical random access channel (PRACH)-based timing advance (TA) update indication associated with a PRACH-based TA update operation corresponding to at least one deactivated cell. The UE may transmit a PRACH message to the at least one deactivated cell to facilitate updating a TA associated with the at least one deactivated cell. Numerous other aspects are described.