UE Network Selection for Service Continuity During Overload
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Solution Overview
Problem
Current cellular network mechanisms, such as Access Class Barring (ACB) and Extended Access Barring (EAB), fail to provide continued service to Machine Type Communication (MTC) devices during network overload conditions, leading to service disruptions and battery drain, as they do not allow for alternative network access when the primary network is overwhelmed.
Innovation Solution
A method and system that enable user equipment (UE) to change its network selection behavior by receiving an 'unable to serve' indication from the primary network, allowing it to immediately connect to a secondary network or the same network with a different radio access technology, thereby ensuring continued service during severe network failure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Access Class Barring (ACB) and Extended Access Barring (EAB) mechanisms are used to manage network overload, then network resource consumption is reduced, but service continuity is lost and battery drain increases
Solution Approach 1:
The patent implements dynamic PLMN selection behavior that adapts based on network conditions. When the primary network provides an 'unable to serve' indication, the UE dynamically switches from attempting to attach to the primary network to selecting an alternative PLMN. This dynamic adaptation resolves the contradiction by enabling service continuity (improving reliability) while avoiding unnecessary access attempts that would drain battery (reducing energy loss).
Solution Approach 2:
The patent introduces an intermediary mechanism - the 'unable to serve' indication from the primary network - that mediates between the UE's attachment attempts and the network's overload state. This indication triggers the UE to switch to alternative PLMN selection, thereby maintaining service continuity without exhausting battery power through futile reconnection attempts to the overloaded network.
2Reliability
If UEs keep trying to attach to the primary network during overload conditions, then service availability is maintained, but network resources are consumed unnecessarily and battery power is drained faster
Solution Approach 1:
The patent employs feedback through the 'unable to serve' indication sent from the primary network to the UE. When the network is in an unable-to-serve state, it provides this feedback to the UE, which then switches to alternative PLMN selection. This feedback mechanism ensures service availability is maintained through alternative networks while preventing unnecessary battery consumption from continuous attachment attempts to the overloaded primary network.
3Reliability
If the PLMN selection hierarchy is strictly followed with preprogrammed SIM entries, then network security and operator control are maintained, but alternative network access is blocked during primary network failure
Solution Approach 1:
The patent makes the PLMN selection process dynamic by allowing the UE to deviate from the preprogrammed hierarchy when the primary network indicates an 'unable to serve' state. The UE dynamically switches to selecting an alternative PLMN from available networks, thereby maintaining network security through controlled selection while enabling adaptability to network failures.
Solution Approach 2:
The patent changes the selection parameter from strictly following the preprogrammed PLMN hierarchy to considering alternative PLMNs when the primary network provides an 'unable to serve' indication. This parameter change enables the system to maintain security through controlled selection processes while adapting to network conditions by allowing alternative access paths.
4Loss of energy
If Access Class Barring is implemented to reduce network overload, then network resource consumption is reduced, but MTC devices experience service disruptions and no-service scenarios
Solution Approach 1:
The patent introduces an intermediary mechanism that works in conjunction with ACB/EAB - the 'unable to serve' indication - which triggers alternative PLMN selection. This intermediary allows the network to implement resource conservation through ACB while simultaneously providing a pathway for service continuity through alternative network selection, resolving the contradiction between resource conservation and service reliability.
Solution Approach 2:
The patent adds a dynamic layer to the static ACB/EAB mechanism by enabling UE to switch to alternative PLMNs when unable-to-serve conditions are detected. This dynamic response allows network resource consumption to be reduced through ACB while service continuity is maintained through adaptive network selection, resolving the contradiction between these two objectives.
Data Source
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AI summary
A method and system for providing a continued service to user equipment (UE) under overload conditions is disclosed. A primary network undertakes a protective measure under unable to serve conditions by commanding a change in the UE network access behavior so that the UE can move to the secondary PLMN. After receiving the indication from the primary network, the UE connects to the secondary network and continues to obtain the services from the secondary network. The secondary PLMN ID can be sent to the UE in system information. Further, the information like overload indication, secondary PLMN ID and the time for which the UE can obtain the services from the secondary PLMN ID can be sent to individual UEs over dedicated messages either on an Access Stratum (AS) message or over a Non Access Stratum (NAS) message.