Overlapping Beam Handover Between Cellular Nodes for High-Speed UEs
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Solution Overview
Problem
Existing cellular networks face challenges in making stable and safe handovers for user equipment (UEs) moving at high speeds, such as in cars or trains, due to insufficient time to gather radio metrics for decision-making during inter-cell mobility.
Innovation Solution
A system with two nodes along a track, each having multiple beams, where the last beam of one node coincides with the first beam of the next node, allowing the source node to initiate handover based on beam changes without waiting for UE metrics, ensuring seamless transition to the target node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the source node waits for radio metrics reports from the UE to make handover decisions, then the handover decision can be based on comprehensive radio quality information, but the handover time is delayed and insufficient for fast-moving UEs
Solution Approach 1:
The patent applies preliminary action by pre-configuring overlapping beams at the boundary between cells before handover is needed. The target node's first beam overlaps with the source node's last beam, creating a prepared handover area. When the UE enters this overlapping region, the source node can immediately initiate handover without waiting for radio metrics reports, as the beam overlap already indicates the UE is in the appropriate handover zone.
2Area of stationary object
If the cell radius is large to cover more area, then fewer cells are needed along the track, but the handover decision time becomes insufficient for fast-moving UEs
Solution Approach 1:
The patent applies segmentation by dividing each cell into multiple sections along the track, each covered by a different beam. The last beam of one cell and the first beam of the next cell create an overlapping handover section. This segmentation allows the system to maintain large cell radii for area coverage while creating dedicated handover zones that provide sufficient time for handover decisions regardless of UE speed.
3Productivity
If multiple beams are used per cell to enhance spatial multiplexing and intra-cell mobility, then the load capacity and beam gain are improved, but the handover decision complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific functions to specific beams: the last beam of each cell is configured to overlap with the first beam of the next cell to create a handover detection zone. This local specialization allows the system to use multiple beams for spatial multiplexing and intra-cell mobility while simplifying inter-cell handover decisions, as the source node only needs to detect when the UE enters the overlapping beam region to initiate handover.
Data Source
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AI summary
A system (1) comprises a first and a second node (2i) for a cellular network, each node (2i) having at least two different beams (8i,k) for wireless communication with a user equipment (3) via one of the beams (8i,k) , wherein each beam (8i,k) of the first node (21) covers a different one of a first succession of sections (101,k) of a track (4), each beam (82,k) of the second node (22) covers a different one of a second succession of sections (102,k) of the track (4), the last section (101,3) in the first succession and the first section (102,1) in the second succession coincide, and the first node (21) sends a handover request (HR) regarding a user equipment (3) to the second node (22) when the beam (8i,k) selected for wireless communication with said user equipment (3) changes from the beam (81,2) that covers the last but one section (81,2) of the first node (21) to the beam (81,3) that covers the last section (81,3) of the first node (21).