Mobile Relay Wireless Handover Detection
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Solution Overview
Problem
High-speed rail systems face frequent and time-critical wireless service handovers due to the rapid movement of trains through cellular coverage areas, requiring a quick and reliable handover scheme to maintain communication services.
Innovation Solution
A wireless service handover method that involves detecting handover targets, measuring received signals, determining approach or departure status, and transmitting reports to facilitate timely handovers between donor eNodeBs, using both periodic and event-based reporting techniques to optimize handover decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the train travels at high speed through cellular coverage areas, then the mobile relay can provide wireless communication services to users, but the handover frequency between donor eNodeBs increases significantly
Solution Approach 1:
The mobile relay performs measurements on neighboring donor eNodeBs in advance and prepares handover information before actual handover is needed. The measurement time period is reduced and measurements are conducted proactively as the train approaches coverage area boundaries, allowing the network to prepare handover commands ahead of time and execute them quickly when needed.
2Loss of time
If the measurement time period for handovers is reduced, then handover decisions can be made more quickly, but the accuracy of signal quality assessment may be compromised
Solution Approach 1:
The mobile relay continuously monitors signal quality metrics including RSRP, RSRQ, and SINR of both serving and neighboring donor eNodeBs. This continuous feedback mechanism allows for rapid assessment of signal conditions with reduced measurement periods, as the system accumulates quality data over time and can make accurate handover decisions based on trends rather than requiring lengthy single measurements.
3Productivity
If frequent handovers are performed to maintain service continuity, then users can remain connected during high-speed travel, but service disruptions may occur during the handover process
Solution Approach 1:
The system prepares handover information in advance by measuring neighboring donor eNodeB signals and pre-configuring handover parameters before the actual handover execution. This preliminary preparation allows for smoother, faster handover transitions that minimize service disruptions to users during the high-speed train's movement between coverage areas.
Data Source
AI summary
A method, a mobile relay using the same and a DeNB using the same are proposed. The present disclosure reduces the time required to perform wireless service handover by detecting the movement status of the mobile relay relative to a candidate DeNB as to determine whether a mobile relay is approaching or leaving a candidate handover DeNB. By incorporating the movement status into a report sent to the serving DeNB, the serving DeNB would require less time to make handover decisions since the reporting interval could be reduced to one interval, and the time to trigger would not be required. The movement status could be determined based on the propagation time of signals, a list of neighbor cell information, or the Doppler effect.