Conditional PSCell Configuration for Low-Delay 5G Handover
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Solution Overview
Problem
Existing mobile communication systems face delays during conditional handover when multiple secondary cell groups (SCGs) are established or changed, particularly in scenarios involving a target master node transferring configuration information to a user equipment (UE).
Innovation Solution
Implementing a method for conditional handover (CHO) and conditional PSCell addition and change (CPAC) by transmitting specific indicators and configuration information between base stations to ensure seamless handover without additional signaling delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conditional handover is performed with multiple secondary cell groups, then handover reliability is improved, but handover delay increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple secondary cell groups (SCGs) with their respective PSCell configurations before handover execution. The source base station prepares conditional reconfiguration information including multiple candidate PSCell configurations in advance, and the target base station pre-establishes SCG configurations. This allows the UE to immediately switch to a pre-configured PSCell when handover conditions are met, avoiding delays from post-handover configuration establishment while maintaining reliable connectivity through multiple pre-prepared SCG options.
2Reliability
If configuration information is transferred between base stations during handover, then handover completeness is improved, but signaling complexity increases
Solution Approach 1:
The patent merges the configuration information transfer process by consolidating multiple PSCell configuration details into a single conditional reconfiguration information message. The source base station aggregates configuration data from multiple target base stations and incorporates them into one RRC reconfiguration message that includes conditional execution conditions. This merging approach ensures complete handover configuration while reducing the number of separate signaling exchanges between base stations and the UE, thereby lowering overall signaling complexity.
Data Source
AI summary
The present invention relates to a method of a first base station, comprising the steps of: determining whether or not to perform conditional handover (CHO) and conditional PSCell addition and change (CPAC) for a terminal; transmitting, to a candidate target base station of the CHO, a handover request message including an indicator for the CHO and an indicator regarding performance of the CPAC; receiving, from the candidate target base station, a handover response message including configuration information for performing the CPAC; and transmitting, to the terminal, on the basis of the configuration information, a radio resource control (RRC) reconfiguration message including conditional reconfiguration information for performing the CHO and the CPAC, wherein the conditional reconfiguration information includes a configuration for the candidate target base station and a configuration for each of at least one candidate secondary cell group related to the CPAC.