RRC Handover Status Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for handover in wireless networks fail to effectively synchronize the status of a mobile device between a source node and a target node without increasing signaling, leading to potential mismatches and inefficiencies during the handover process.
Innovation Solution
Utilizing existing Radio Resource Control (RRC) reconfiguration messages to exchange status reports between the mobile device and the target node during handover preparation and execution, ensuring synchronization without additional signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If status reports are exchanged using additional signaling during handover, then synchronization accuracy between mobile device and target node is improved, but network signaling overhead increases
Solution Approach 1:
The patent merges the status report exchange with existing handover signaling messages (RRCConnectionReconfiguration and RRCConnectionReconfigurationComplete). Instead of using separate additional signaling messages, the assistance information is embedded within the handover procedure messages that are already being exchanged between the mobile device and network nodes, thus achieving synchronization without increasing overall signaling overhead.
Solution Approach 2:
The existing handover messages are made multi-functional by incorporating dual purposes: they simultaneously perform handover configuration/confirmation and status report exchange. The RRCConnectionReconfiguration message carries both handover parameters and assistance information from the target node, while RRCConnectionReconfigurationComplete carries both acknowledgment and updated status information, eliminating the need for dedicated status report messages.
2Measurement precision
If frequent status reports are transmitted to maintain synchronization, then status accuracy is improved, but excessive signaling occurs
Solution Approach 1:
The patent implements periodic status report exchange aligned with the handover procedure timeline. Status information is exchanged at specific periodic points: once during handover preparation (target node provides assistance information in RRCConnectionReconfiguration) and once during handover execution (mobile device confirms in RRCConnectionReconfigurationComplete). This periodic approach ensures synchronization without continuous signaling.
Solution Approach 2:
The target node prepares and provides assistance information in advance during the handover preparation phase, before the mobile device actually executes the handover. This preliminary action ensures that the mobile device receives accurate status information about the target node's configuration and capabilities beforehand, enabling smooth handover without requiring additional post-handover status exchanges.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The UE, source eNodeB, and/or target eNodeB use one or more existing Radio Resource Control (RRC) messages already available during handover to exchange at least one status report comprising UE assistance information, such as power preference indicators (PPI). The UE and the target eNodeB are thus able to obtain the same up-to-date UE status without any additional signaling. In one embodiment, the UE exchanges a handover preparation status report with the target eNodeB using a first RRC reconfiguration message transmitted from the source eNodeB to the UE, where the handover preparation status report is generated during handover preparation by the target eNodeB. In another embodiment, the UE exchanges a handover execution status report with the target eNodeB during handover execution using a second RRC reconfiguration message transmitted from the UE to the target eNodeB, where the handover execution status report is generated during handover execution. In another embodiment, the UE exchanges multiple status reports with the target eNodeB using multiple RRC reconfiguration messages, where the status reports are generated during handover preparation and handover execution. The handover preparation status report is transmitted from the target eNodeB to the UE and includes the status report as perceived by the target node at the time of handover preparation. The handover execution status report is transmitted from the UE to the target eNodeB and includes the status report as stored in the UE memory at the time of handover execution. The first RRC reconfiguration message is a RRC connection reconfiguration message and the second RRC reconfiguration message is a RRC connection reconfiguration complete message.