Relay Node Handover via DeNB Identifier Allocation
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Solution Overview
Problem
In relay networks, when an X2 interface is unavailable between a relay node (RN) and a control base station (DeNB), the Mobility Management Entity (MME) cannot determine the corresponding DeNB, preventing a correct handover request and thus hindering the handover process from an eNB to the RN.
Innovation Solution
The DeNB allocates a unique identifier, such as an EUTRAN Cell Global Identifier (ECGI) or Tracking Area Identity (TAI), to the RN, allowing the RN to broadcast this identifier to UEs, enabling the MME to obtain the DeNB ID and facilitate a handover request through the MME, ensuring seamless handover even without an X2 interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If handover is performed through S1 interface connected to MME in relay network, then handover can be performed without X2 interface, but MME cannot determine the DeNB corresponding to the RN, causing handover request cannot be correctly sent
Solution Approach 1:
The DeNB pre-allocates a unique area identifier (ECGI or TAI) to the RN before handover occurs. This identifier is configured in advance and stored by the RN, enabling the MME to determine the DeNB when the RN later provides this identifier during handover signaling.
Solution Approach 2:
A unique area identifier (ECGI or TAI) acts as an intermediary between the RN and DeNB. The identifier encapsulates DeNB identification information and is transmitted through the MME, enabling the MME to correctly route handover requests to the appropriate DeNB without requiring direct X2 interface connectivity.
2Reliability
If DeNB allocates unique identifier to RN, then MME can correctly identify DeNB and send handover request, but requires additional identifier allocation and configuration signaling
Solution Approach 1:
The area identifier (ECGI or TAI) allocated to the RN serves multiple functions: it uniquely identifies the RN's serving area, enables MME to determine the DeNB, and facilitates handover signaling. This multi-functional approach avoids the need for separate dedicated identifier mechanisms.
Solution Approach 2:
The DeNB allocates and configures the area identifier to the RN in advance during initial setup or configuration phases. This preliminary action ensures the identifier is ready when needed for handover, eliminating the need for real-time allocation during the critical handover process.
Data Source
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AI summary
Embodiments of the present invention provide a handover method and system in a relay network, a relay node, a control base station and a base station. The method includes: receiving, by a relay node, a first area identifier that identifies the relay node; sending a system information broadcast message carrying the first area identifier to a terminal in a coverage area; receiving a handover request message forwarded by a control base station; and performing, according to the handover request message, a control operation of accessing the relay node on the terminal. The relay node includes: a first receiving module, a first sending module and a processing module. The control base station includes: a second sending module and a second receiving module. The base station includes: a third receiving module and a third sending module. The system includes: a relay node, a control base station, a base station and a mobility management entity. The first area identifier that identifies the relay node is allocated to the relay node, so that the terminal in the relay network can be normally handed over from the base station to the relay node.