5G Cell Handover via Layer 1 Pre-Synchronization
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Solution Overview
Problem
In 5G wireless communication systems, traditional cell handover methods based on Layer 3 signaling result in significant switching delays, leading to service quality degradation, especially in scenarios requiring low latency, and pose challenges in coordinating radio link failures with the switching process to avoid communication interruptions.
Innovation Solution
A method that utilizes Layer 1 measurements and MAC layer signaling to facilitate cell handover, allowing for pre-synchronization and reducing switching delays, while coordinating radio link failures to ensure continuous data transmission and minimize interruptions during the switching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Layer 3 RRC signaling is used for cell handover, then the switching process is reliable and coordinated, but the switching delay increases to several tens of milliseconds to one or two hundred milliseconds
Solution Approach 1:
The patent applies preliminary action by performing downlink synchronization and preparing handover configuration information in advance at the target cell before the actual handover is triggered. The terminal pre-loads target cell parameters and performs synchronization operations beforehand, so that when handover is initiated, the terminal can quickly switch without performing these time-consuming operations from scratch, thereby reducing switching delay while maintaining reliability
Solution Approach 2:
The patent segments the handover process into distinct phases: preparation phase (target cell synchronization and configuration), execution phase (actual switching), and completion phase (uplink synchronization). By separating these phases and overlapping the preparation phase with the current serving cell connection, the patent reduces the critical path delay while ensuring each phase is completed reliably
2Productivity
If cell handover frequency increases to meet 5G service requirements, then service quality improves, but communication interruptions and service quality degradation due to switching delay become more serious
Solution Approach 1:
The patent enables faster handover execution through preliminary synchronization and configuration loading, which reduces the time penalty of each handover. This allows the system to perform more frequent handovers to track mobile users through small cells without accumulating excessive delay, thereby maintaining service quality even with increased handover frequency
Solution Approach 2:
The patent maintains continuity of useful action by overlapping the handover preparation phase with the current connection, ensuring that data transmission continues without interruption while synchronization and configuration are being prepared. This minimizes the impact of each handover on service continuity, enabling more frequent handovers without degrading overall service quality
3Reliability
If RRC connection re-establishment is performed when radio link failure occurs, then connection is restored, but communication interruption occurs and the switching process is interrupted
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring failure recovery parameters and alternative cell information during normal operation. When radio link failure occurs, the terminal can immediately activate these pre-prepared recovery mechanisms without interrupting the handover process, thereby restoring connection while maintaining service continuity
Solution Approach 2:
The patent introduces an intermediary mechanism where the terminal can temporarily maintain connection to the current cell or a pre-selected alternative cell while the target cell handover is completing, even if radio link failure is detected. This intermediary state allows the handover process to continue without interruption while providing fallback protection, thus restoring connection without causing service interruption
Data Source
AI summary
A method and device for wireless communications, comprising receiving a first signaling; the first signaling comprising a first cell identity, the first cell identity being configured to a target Special Cell (SpCell); detecting a first event; herein, the first event belongs to a first candidate event set, the first candidate event set comprises at least one of a first timer being expired, receiving an indication of MAC of an MCG related to a problem occurring in random access procedure, receiving an indication of RLC of an MCG related to reaching a maximum number of retransmissions, or receiving an indication of MAC of an MCG related to continuous uplink listen before talk (LBT) failure; the behavior of detecting whether a first event triggers radio link failure is related to whether there is an ongoing first signaling procedure. The present application can achieve better mobility management through a first signaling.