Mobility Management Entity Session Context Continuity
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Solution Overview
Problem
Current wireless communication systems face challenges in maintaining session context continuity and efficient handover of local IP connectivity when user equipment (UE) moves between different serving gateways, particularly in femto cell and Home NodeB (HNB) environments, leading to disruptions in LIPA and SIPTO services.
Innovation Solution
The implementation of a method within the mobility management entity that supports simultaneous use of multiple serving gateways, involving requests to create and delete session contexts, and the use of specific messages like CREATE SESSION REQUEST and Delete Session Request to manage handovers and connectivity types, ensuring seamless LIPA and SIPTO service continuity across different network access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a UE moves between different serving gateways in femto cell environments, then network coverage is extended, but session context continuity is disrupted
Solution Approach 1:
The patent establishes session contexts in advance at multiple serving gateways before handover occurs. When a UE moves between femto cells, the target serving gateway already has a pre-established session context, enabling seamless continuity without disruption. This preliminary setup of session contexts at potential target gateways resolves the contradiction by preparing the network infrastructure ahead of time.
Solution Approach 2:
The patent introduces the mobility management entity (MME) as an intermediary that coordinates session context establishment and handover between serving gateways. The MME manages the session contexts and ensures continuity by orchestrating the interaction between source and target gateways during UE movement, preventing session disruption while enabling network coverage extension.
2Reliability
If local IP connectivity is maintained during handover, then service continuity is improved, but handover efficiency is reduced
Solution Approach 1:
The patent pre-establishes session contexts at target serving gateways before handover execution. This preliminary action includes setting up the necessary IP connectivity paths in advance, so that when handover occurs, the UE can seamlessly switch to the target gateway without service interruption. The LIPA and SIPTO service contexts are prepared beforehand, maintaining service continuity while streamlining the actual handover process.
3Adaptability or versatility
If multiple serving gateways are used simultaneously, then service availability is improved, but network complexity increases
Solution Approach 1:
The patent makes the mobility management entity universal by enabling it to manage session contexts across multiple serving gateways with a unified approach. The MME handles LIPA, SIPTO, and remote connectivity scenarios through a common session context management mechanism, allowing multiple gateways to be used simultaneously without proportionally increasing complexity. The same MME can serve multiple gateways using standardized procedures.
Solution Approach 2:
The MME acts as an intermediary that simplifies the complexity of managing multiple serving gateways. Instead of direct complex interactions between UEs and multiple gateways, the MME mediates all session context management, handover coordination, and connectivity establishment. This central mediation reduces overall network complexity while enabling versatile service availability across multiple gateways.
Data Source
AI summary
Local IP Access (LIPA) allows an IP-capable user equipment (UE) connected via a femto cell direct access to other IP-capable devices in the local IP network. Selected IP Traffic Offload (SIPTO) is used to offload selected types of IP traffic towards a defined IP network close to the UE's point of attachment to the access network. LIPA PDN Connectivity indicates a PDP Context or a PDN Connection that gives access to services located in the local IP network of the femto cell subsystem. SIPTO PDN Connectivity indicates a PDP Context or PDN Connection that allows offload of selected types of IP traffic towards a defined IP network close to the UE's point of attachment to the access network. Systems, devices and methods are described herein that enable the identification of the type of connectivity available to a UE and enable session continuity for local cellular coverage.