NTN Cell Change Control Using Conditional Uplink Assistance
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Solution Overview
Problem
Conventional handover techniques in non-terrestrial networks (NTNs) are inadequate due to frequent cell changes, high signaling overhead, and unsuitable path loss measurements, particularly for satellites in low-earth orbits and airborne vehicles, leading to inefficient resource usage and increased power consumption.
Innovation Solution
Implementing uplink mobility with conditional handover optimization, where infrastructure equipment transmits conditions for the communications device to send assistance information, such as uplink reference signals, based on location, time, or signal quality thresholds, to optimize handover decisions and reduce unnecessary signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional handover techniques are used in NTNs, then connectivity can be maintained, but signaling overhead increases and power consumption rises due to frequent cell changes
Solution Approach 1:
The patent implements conditional handover by pre-configuring handover conditions and assistance information (such as uplink reference signals) before handover is needed. The communications device monitors whether these pre-configured conditions are met, and only performs handover when conditions are satisfied. This preliminary configuration approach reduces frequent handover executions and associated power consumption while maintaining connectivity reliability.
2Reliability
If conventional handover techniques are used in NTNs, then connectivity can be maintained, but signaling overhead increases due to frequent cell changes
Solution Approach 1:
The network infrastructure equipment pre-configures handover conditions and assistance information (including uplink reference signals) before handover is needed. The communications device only triggers handover when pre-defined conditions are met, significantly reducing the frequency of handover signaling exchanges. This preliminary configuration approach minimizes redundant signaling overhead while ensuring connectivity is maintained through condition-based handover execution.
3Measurement precision
If uplink reference signals are transmitted frequently, then handover decisions can be optimized, but power consumption increases
Solution Approach 1:
The network pre-configures the communications device with specific conditions for transmitting uplink reference signals and provides assistance information in advance. The device only transmits these signals when the pre-defined conditions are met (such as when entering specific geographic areas or when signal quality thresholds are crossed). This conditional approach based on pre-configured parameters reduces unnecessary reference signal transmissions and associated power consumption while maintaining accurate handover decision-making through targeted measurements.
Data Source
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AI summary
A method for operating an infrastructure equipment forming part of a wireless communications network is provided. The wireless communications network comprises a base station and a non-terrestrial network part, the non-terrestrial network part transmitting one or more spot beams to provide a wireless access interface for transmitting signals to and receiving signals representing data from a communications device within a coverage region of a cell or one of the spot beams, the spot beam forming a cell. The method comprises transmitting, to the communications device, an indication of a first condition to be met before the communications device should transmit assistance information to the infrastructure equipment, receiving the assistance information from the communications device upon the first condition being met, determining, based on the assistance information, that a cell change of the communications device should be initiated, and initiating the cell change of the communications device.