D2D Handover Coordination for ProSe Service Continuity
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Solution Overview
Problem
Current LTE systems face challenges in supporting seamless device-to-device (D2D) handover, leading to interruptions in ProSe services due to latency and excessive signaling, especially when ProSe capable UEs move across cell boundaries, affecting the continuity of D2D communications.
Innovation Solution
A method and control node architecture that determines and facilitates handover decisions for D2D communications by measuring signal quality and triggering handovers between control nodes, allowing UEs to handover jointly or successively, minimizing extra signaling and ensuring ProSe service continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LTE handover procedure is used for D2D communications, then handover can be performed between cells, but D2D communication continuity is interrupted and extra signaling is required
Solution Approach 1:
The patent merges the handover procedures of multiple ProSe capable UEs into a single coordinated handover operation. When multiple UEs engaged in D2D communication need to handover to the same target cell, the source eNB coordinates with the target eNB to perform the handover simultaneously, thereby maintaining D2D communication continuity and reducing signaling overhead by avoiding repeated handover procedures.
Solution Approach 2:
The patent implements preliminary actions by having the source eNB send a handover request to the target eNB before the actual handover execution. The handover request includes information about multiple ProSe capable UEs that need to handover, allowing the target eNB to prepare resources in advance. This preliminary coordination enables seamless handover and maintains D2D communication continuity.
2Ease of operation
If ProSe capable UEs perform handover individually in LTE system, then each UE can be handed over to neighboring cell, but D2D communication is interrupted and requires re-establishment
Solution Approach 1:
The patent combines individual UE handover operations into a unified group handover procedure. The source eNB identifies multiple ProSe capable UEs that need to handover to the same target cell and coordinates their handover simultaneously. This merging of handover operations ensures that D2D communication links are maintained throughout the handover process, preventing communication interruption and maintaining ProSe service continuity.
Solution Approach 2:
The patent implements feedback mechanisms where the source eNB receives measurement reports from ProSe capable UEs about signal quality and uses this information to make coordinated handover decisions. The target eNB also provides feedback regarding resource availability and handover readiness. This feedback loop ensures that handover is executed smoothly while maintaining D2D communication continuity.
Data Source
AI summary
A method of performing a handover procedure for device-to-device (D2D) communications and a control node thereof are proposed. The method is applicable to a first control node serving a D2D communication between a first user equipment (UE) and a second UE. The method includes: determining that one of the first UE and the second UE needs to be handed over or both of the first UE and the second UE need to be handed over; transmitting a handover request to a second control node if the first control node determines that both of the first UE and the second UE need to be handed over to the second control node; receiving a handover request acknowledgement from the second control node; and transmitting a handover command to indicate the first UE and the second UE to detach from the first control node and synchronize to the second control node.