X2 Gateway Coordination for Faster S1-X2 Handovers
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Solution Overview
Problem
Existing radio networks face challenges in optimizing S1-X2 handovers due to the lack of efficient methods for creating X2 associations between virtual and macro eNodeBs, leading to increased signaling and suboptimal performance in virtualized environments.
Innovation Solution
A system is introduced that enhances the HNG X2GW node to support optimized S1-X2 handovers by loosely coupling it with a SON module, allowing the X2GW to learn cell information from S1AP handover messages and initiate X2 association setups, thereby enabling seamless handovers even when neighbor relations are not pre-notified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If X2 association is pre-configured between all eNodeBs, then handover speed is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing X2 associations only for necessary neighbor relations during eNodeB startup or configuration phase, rather than maintaining all possible associations. The X2GW node proactively sets up X2 connections with peer eNodeBs based on pre-configured neighbor information, enabling fast handovers when needed while avoiding the complexity of managing all possible X2 associations in advance.
2Productivity
If X2 interface is used for handover, then handover efficiency is improved, but the requirement for pre-established X2 associations increases device complexity
Solution Approach 1:
The patent implements self-service through the X2GW node that automatically discovers and establishes X2 associations with peer eNodeBs based on pre-configured neighbor information. The system autonomously manages the X2 association setup, maintenance, and teardown without requiring manual configuration or complex centralized management, thereby improving handover efficiency while keeping device complexity manageable through automated operations.
3Device complexity
If S1 interface is used exclusively for handover, then device complexity is reduced, but handover speed and efficiency deteriorate
Solution Approach 1:
The patent applies dynamics by implementing a flexible handover mechanism that can dynamically select between S1 and X2 interfaces based on the availability of X2 associations and handover requirements. The system transitions from static S1-only handover to dynamic multi-interface handover, where X2 interface is used when associations exist (faster handover) and S1 interface is used as fallback (simpler management), thereby optimizing both speed and complexity trade-offs.
4Adaptability or versatility
If virtual eNodeBs are introduced for network virtualization, then adaptability and scalability are improved, but the complexity of managing X2 associations between virtual and macro eNodeBs increases
Solution Approach 1:
The patent introduces the X2GW node as an intermediary that simplifies X2 association management in virtualized networks. The X2GW acts as a gateway that handles X2 signaling between virtual eNodeBs and macro eNodeBs, abstracting the complexity of cross-virtualization-domain association management. This intermediary approach enables adaptability and scalability of virtualized networks while managing X2 association complexity through centralized gateway control.
Data Source
AI summary
A system is disclosed to enhance HNG X2GW node in a way so that it supports the optimized S1-X2 Handovers with loosely coupled SON module. X2GW module in HNG interworks with SON module to provide interface for/towards SON module to update the information required for X2 association management. On receiving cell information from CWS, SON updates the X2GW with additional parameters required for creating/updating X2 association. When SON receives UE measurement report from CWS, it updates the same to X2GW with neighbor information to take further action. For S1-X2 handover where SON has not notified X2GW of neighbor relation between CWS and Macro eNodeB, HNG continues sending Handover over S1. X2GW views SON as a DB which holds Cell Neighbor Related information and keeps updating x2 learnt neighbours using well defined API's towards SON.