5G Air-to-Ground Handover Using Propagation Delay and Trajectory
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Solution Overview
Problem
In the 5G NR air-to-ground communication system, handover procedures in open space environments often fail due to the difficulty in identifying the most suitable target cell, leading to ping-pong handovers or incorrect cell selection, as existing methods solely rely on signal measurements without considering neighbor base station proximity and aircraft trajectory.
Innovation Solution
A handover algorithm that selects the target cell based on both distance and trajectory criteria, using propagation delay and its rate of change to determine the most suitable neighbor cell for handover, in addition to traditional signal strength and quality measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If handover selection is based solely on signal measurements (RSRP/RSRQ/SINR), then the handover decision is simple and fast, but handover accuracy deteriorates leading to ping-pong handovers and incorrect cell selection
Solution Approach 1:
The patent extends the handover decision from a one-dimensional signal strength comparison to a multi-dimensional assessment by incorporating propagation delay measurements. This additional dimension allows the system to distinguish between nearby and distant base stations with similar signal strengths, thereby improving handover accuracy without excessive complexity increase
Solution Approach 2:
The patent changes the parameters used for handover decision from purely signal quality metrics (RSRP, RSRQ, SINR) to include propagation delay characteristics. By monitoring both signal strength and propagation delay, the system can identify the most suitable target cell more accurately, reducing ping-pong effects while maintaining manageable decision complexity
2Productivity
If the transceiver equipment selects a neighbor cell with higher signal strength regardless of distance, then handover is straightforward, but service continuity deteriorates due to ping-pong handovers
Solution Approach 1:
The patent performs preliminary propagation delay measurements and trajectory analysis before executing handover. By pre-assessing the propagation delay characteristics and rate of change, the system can predict future signal conditions and select target cells that will maintain service continuity, preventing ping-pong handovers while keeping execution efficient
Solution Approach 2:
The patent implements feedback mechanisms where the transceiver equipment continuously monitors propagation delay and its rate of change, using this information to adjust handover decisions. This feedback loop ensures that handover selections are based on both current signal conditions and predicted future conditions, maintaining service continuity without sacrificing handover speed
Data Source
AI summary
The invention relates to a method for handover of a transceiver equipment, in particular UE and/or on-board equipment (OBE), from a serving cell to a target cell in a cellular communications network, said serving cell belonging to a first base station and said target cell belonging to a second base station, and said target cell being selected from a group of neighbor cells being better than the serving cell by an offset, wherein the method comprises: I. transmitting a measurement report to the first base station, said measurement report comprising information on a neighbor cell selected from the group of neighbor cells, based on i. a distance criterion, and optionally ii. a trajectory criterion, II. receiving a handover command from the first base station, said handover command comprising instruction for handover to the selected neighbor cell becoming the target cell, and III. completing handover with the second base station.