User Equipment Beam Refinement Before Handover to Reduce Interruption Time
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Solution Overview
Problem
Conventional beam management techniques in handover situations in wireless networks suffer from excessive delays due to the time required for beam refinement procedures, which are typically performed after handover completion, leading to inefficiencies and increased interruption times.
Innovation Solution
Perform beam refinement before or during the handover process by providing a repetition configuration of channel state information reference signal (CSI-RS) resource indices to user equipment (UE) for random access, allowing early alignment of narrow beams and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam refinement procedures are performed after handover completion, then the handover procedure is completed, but excessive delays and increased interruption times occur
Solution Approach 1:
The patent applies preliminary action by performing beam refinement procedures before handover completion. Specifically, the source base station transmits CSI-RS resources to the UE during the handover preparation phase, allowing the UE to perform beam refinement and measurements on the target cell before actually switching. This提前 beam alignment reduces the interruption time during actual handover execution while ensuring reliable connection establishment.
2Reliability
If conventional beam management techniques are used, then handover is completed, but excessive delays occur due to post-handover beam refinement
Solution Approach 1:
The patent implements preliminary action by initiating beam refinement procedures during the handover preparation phase rather than after completion. The source base station provides CSI-RS resource configurations to the UE in advance, enabling the UE to perform beam measurements and refinements on the target cell before the handover executes. This提前 preparation significantly improves handover efficiency by reducing the time the UE needs to spend on beam alignment after switching cells.
Solution Approach 2:
The patent uses CSI-RS (Channel State Information Reference Signal) as an intermediary element to enable beam refinement before handover. The source base station transmits CSI-RS resources that allow the UE to measure and refine beams for the target cell without actually being connected to it yet. This intermediary mechanism facilitates early beam alignment while maintaining connection with the source cell, thereby improving overall handover productivity.
3Reliability
If narrow beams are set up after handover, then connection is established, but link budget and robustness for cell edge UEs are reduced
Solution Approach 1:
The patent applies preliminary action by establishing narrow beam connections before handover completion. The UE performs beam refinement and identifies optimal narrow beams for the target cell during the preparation phase using CSI-RS resources provided by the source base station. This提前 narrow beam setup ensures that when the handover executes, the UE can immediately use robust narrow beam connections, significantly improving link budget and signal strength for cell edge users who are more vulnerable to signal degradation.
Data Source
AI summary
Improved techniques of beam management in a HO situation include receiving, at a source node from a candidate target node after receiving a measurement report from a UE prior to completion of a HO, a repetition configuration of a channel state information reference signal (CSI-RS) resource index to be used by the UE for random access. When beam refinement occurs during HO, a candidate target cell for HO provides the UE with a repetition configuration of CSI-RS resource index that will be selected and used by the UE for random access to the target cell. When beam refinement occurs before HO, the candidate target cell of handover provides the UE (e.g. during the handover preparation phase in case of conditional HO (CHO)) with the repetition configuration of CSI-RS resource index (or indices) whose transmission(s) is repeated while the UE is served by the source cell and before executing a handover.