Cell Level Mobility via Layer 3 Timing Advance in 5G
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The 5G communication system faces challenges in cell level mobility due to the introduction of new services like network energy saving and non-terrestrial networks, which require enhanced conditional reconfiguration to manage changes in network nodes covering geographical areas over short periods.
Innovation Solution
The method involves receiving a Radio Resource Control (RRC) message for cell level mobility, starting a time alignment timer for uplink transmission based on Layer 2 or Layer 3 Time Alignment (TA) information, and performing uplink transmission when the timer is running, ensuring seamless mobility by aligning timing advances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conditional reconfiguration is enhanced to manage rapid network node changes, then mobility support is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring conditional reconfiguration parameters and time alignment information before mobility events occur. The network node provides RRC messages with embedded TA information and timer configurations in advance, allowing the terminal to rapidly execute mobility procedures without real-time negotiation, thus enhancing mobility support while controlling system complexity.
2Measurement precision
If time alignment timer is started based on Layer 3 TA information, then uplink transmission accuracy is improved, but processing time increases
Solution Approach 1:
The patent resolves this contradiction by obtaining Layer 3 time alignment information preliminarily through RRC messages before uplink transmission is needed. The terminal stores this pre-acquired TA information and immediately applies it when the time alignment timer expires or starts, avoiding real-time measurement delays while maintaining high uplink transmission accuracy.
3Adaptability or versatility
If network nodes change coverage areas frequently, then service flexibility is improved, but mobility management difficulty increases
Solution Approach 1:
The patent introduces an intermediary mechanism where the network node acts as a mediator by providing centralized RRC messages containing time alignment information and conditional reconfiguration parameters. This intermediary approach allows frequent network node changes and coverage area adjustments while the terminal simply follows the pre-configured instructions, reducing the terminal's mobility management complexity despite high service flexibility requirements.
Data Source
AI summary
A method and apparatus to support cell level mobility is provided. Method for supporting cell level mobility includes receiving a Radio Resource Control (RRC) message for cell level mobility from a first cell to a second cell, starting a time alignment timer for uplink transmission of the second cell and performing uplink transmission of the second cell in case that the time alignment timer is running. The terminal starts the time alignment timer when uplink timing advance based on layer 2 (L2) Time Alignment (TA) information is applied in case that the RRC message does not comprises a first set of parameters. The terminal starts the time alignment timer when uplink timing advance based on layer 3 (L3) TA information is applied in case that the RRC message comprises the first set of parameters.