Mobile Relay Handover Latency Reduction
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Solution Overview
Problem
Current relay technologies in mobile networks, such as those used in 3GPP LTE-Advanced systems, are designed for stationary relays and do not effectively manage the handover of mobile relays, leading to potential network disruptions and quality of service (QoS) issues when relays move relative to source network nodes.
Innovation Solution
A method and system for managing a moving relay node by ensuring a target network node can support the relay, sending a handover request, establishing an interface between the relay and the target node, and detaching the relay from the source node without waiting for acknowledgement, thereby minimizing handover latency and maintaining QoS for connected user equipment (UEs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used for mobile relays, then the relay can move relative to the source network node, but network disruptions and QoS issues occur due to delayed handover completion
Solution Approach 1:
The target network node performs capability verification and resource preparation in advance before the handover is actually executed. The source network node sends a handover request that includes relay capability requirements, and the target node prepares its configuration and resources beforehand, so that when the handover command is issued, the relay can switch immediately without waiting for target node preparation, thus reducing handover latency while ensuring reliability.
Solution Approach 2:
The patent eliminates the waiting step where the source network node would normally wait for an acknowledgment from the target network node before sending the handover command to the relay. By skipping this acknowledgment wait and sending the handover command immediately based on pre-verified target capability, the handover process is rushed through faster, reducing latency while the target node's prior preparation ensures the handover completes successfully without disruptions.
2Reliability
If the source network node waits for acknowledgment before sending handover command, then handover reliability is improved, but handover latency increases
Solution Approach 1:
The target network node's capability to support the mobile relay is verified in advance through the handover request message exchanged between source and target network nodes. This preliminary verification ensures that when the handover command is sent, the target is already confirmed to be ready, eliminating the need for waiting acknowledgments while maintaining reliability.
Solution Approach 2:
The patent skips the acknowledgment waiting step by sending the handover command to the mobile relay immediately after the target network node indicates it can support the relay. This rushing through of the handover process reduces latency while the prior capability confirmation ensures the skipped acknowledgment step does not compromise handover completion reliability.
3Reliability
If target network node capability is verified in advance, then handover reliability is improved, but signaling overhead increases
Solution Approach 1:
The capability verification process is merged into the existing handover request message flow between source and target network nodes. The target node's ability to support the mobile relay is verified by including capability indicators in the standard handover signaling messages, rather than using separate verification procedures. This merging reduces signaling overhead while maintaining handover success rate.
Data Source
AI summary
A method and network element for managing a relay node that is moving relative to a source network node, the method sending a handover request from a source network node to a target network node to prepare the handover at the target network node; sending a handover command from the source network node to the relay node without waiting for an acknowledgement of the handover request from the target network node; and detaching the relay node from the source network node.