Local Mobile Node for Signaling Load Reduction in Small Cell Handovers
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Solution Overview
Problem
High-speed user equipment (UE) handovers between small cells in mobile communication systems often result in handover failures due to the small coverage area of small cells and excessive signaling load on core network devices like the Mobility Management Entity (MME) and Serving Gateway (S-GW), leading to reduced efficiency and increased handover times.
Innovation Solution
A local mobile node is introduced between the base stations and core network devices, which receives path handover requests and establishes user data paths between the local mobile node and the target base station, allowing user plane data to be transmitted through these paths, thereby reducing the need for signaling exchanges with the MME and S-GW and minimizing handover failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedure is used between small cells, then handover can be completed, but handover failure occurs for high-speed moving UE because the UE moves away from the target cell before handover completion
Solution Approach 1:
The local mobile node performs preliminary actions by pre-establishing user plane paths and maintaining context information for multiple eNBs in advance. When handover occurs, the data path can be quickly switched without waiting for full handover completion, allowing high-speed UE to maintain connectivity even during rapid cell transitions.
Solution Approach 2:
The local mobile node acts as an intermediary between the core network and multiple eNBs. It maintains user plane paths and context information locally, enabling fast path switching during handover without requiring continuous signaling with the MME and S-GW, thus reducing handover time and improving success rate for high-speed UE.
2Reliability
If each UE handover triggers signaling exchange with MME and S-GW, then handover can be completed, but signaling load on core network devices becomes excessively heavy
Solution Approach 1:
The local mobile node extracts the user plane path management function from the core network devices (MME and S-GW). It maintains user plane paths and context information locally, so that during handover, only local path switching is needed without triggering extensive signaling exchanges with the core network, thereby reducing signaling load on MME and S-GW.
Solution Approach 2:
The local mobile node serves as an intermediary that handles user plane path management locally. It maintains context information for multiple eNBs and can quickly switch data paths during handover without requiring continuous involvement of the MME and S-GW, thus completing handover while minimizing core network signaling load.
3Productivity
If small cells are deployed densely to handle increased data traffic, then data offloading capability is improved, but handover frequency increases leading to more signaling overhead
Solution Approach 1:
The local mobile node acts as an intermediary that consolidates user plane path management for multiple small cells. It maintains context information and user plane paths locally, enabling fast path switching during frequent handovers without generating proportional signaling overhead to the core network, thus supporting dense small cell deployment efficiently.
Solution Approach 2:
The local mobile node provides multi-functional capabilities by maintaining context information and user plane paths for multiple eNBs simultaneously. It can serve multiple small cells within its coverage area, handling handovers between them locally without requiring separate core network involvement for each handover, thereby reducing overall signaling overhead.
Data Source
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AI summary
The present invention provides a communications system, a local mobile node, and a base station. The communications system includes an MME, multiple eNBs, and a local mobile node. The local mobile node receives a path handover request sent by a target eNB, and when determining, according to a path handover request message, that a local path handover needs to be performed, establishes a user data path between the local mobile node and the target eNB for UE according to the path handover request, so that user plane data is transmitted between the UE and a serving gateway by using the user data path. In this way, after the UE is successfully handed over between eNBs, only a data transmission path between the local mobile node and the target eNB needs to be changed without a need to change a user data path between the local mobile node and each of the MME and the serving gateway, so that signaling load on the MME can be avoided. In addition, a time consumed by an entire handover procedure is shorter, and a handover failure caused in a conventional manner is avoided.