Moving Relay Node Signaling Mobility State Estimate for LTE Handovers
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Solution Overview
Problem
In the context of LTE-Advanced, moving relay nodes face challenges during handovers to fixed base stations, as the mobility state information of relay-UEs is often misconfigured, leading to radio link failures due to incorrect mobility parameters, especially when transitioning from a moving relay to a target cell.
Innovation Solution
A new Information Element (IE) for the Mobility State Estimate is signaled by the moving relay node to the target cell, ensuring that the relay-UEs are configured with accurate mobility parameters corresponding to their actual mobility state, thereby preventing radio link failures and ensuring seamless handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mobility state information of relay-UEs is not signaled during handover, then the handover procedure is simple, but radio link failures occur due to incorrect mobility parameters
Solution Approach 1:
The mobility state estimate is determined and signaled in advance during the handover preparation phase, before the actual handover execution. This preliminary action ensures that the target base station has accurate mobility information ready, preventing radio link failures without adding complex real-time processing during handover execution.
Solution Approach 2:
The mobility state estimate acts as an intermediary information element that bridges the relay node and target base station during handover. This intermediate signaling provides the necessary mobility context without requiring complex direct interaction or additional measurement procedures between the relay-UE and target base station.
2Reliability
If mobility state estimate is signaled for relay-UEs, then accurate mobility parameters can be configured, but new signaling overhead is introduced
Solution Approach 1:
The mobility state estimate is extracted as a separate, dedicated information element within the existing handover signaling framework. This extraction allows the mobility information to be transmitted efficiently without requiring a complete redesign of the handover protocol, minimizing the impact on existing signaling structures.
Solution Approach 2:
The mobility state estimate information element serves multiple functions: it provides mobility parameter configuration basis, enables accurate handover execution, and supports subsequent mobility management. This multi-functionality justifies the signaling overhead by delivering comprehensive mobility information in a single element.
Data Source
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AI summary
An apparatus is provided which comprises a first connection unit configured to provide connection to a user equipment, and a processor configured to detect whether a handover of the user equipment is required, and, if a handover is required, to establish mobility information regarding the mobility state of the apparatus as mobility information of the user equipment, and to send the mobility information to at least one network element involved in the handover of the user equipment.