SCEF-Based UE Reachability Notification for PSM Traffic Delivery
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Solution Overview
Problem
In mobile wireless communication networks, user equipment in power saving mode (PSM) cannot receive mobile terminated services, leading to rejected traffic delivery and network congestion due to lack of downlink reachability awareness for PSM capable devices.
Innovation Solution
The system allows Application Services to subscribe to triggers via the Service Capability Exposure Function (SCEF) and Mobility Management Entity (MME)/Serving General Packet Radio Service Support Node (SGSN) to notify when a PSM capable user equipment (UE) is available to receive data, enabling efficient communication of mobile terminated data by deactivating PSM upon reachability and re-enabling it post-data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If user equipment is in power saving mode (PSM) to conserve power resources, then battery usage is optimized, but the user equipment is unable to receive traffic for mobile terminated services
Solution Approach 1:
The system performs preliminary actions by notifying application services in advance when a PSM-capable UE is about to become available (before the periodic timer expires). This allows the network to proactively prepare for data delivery by deactivating PSM mode timely, ensuring the UE is reachable when downlink traffic arrives, thus resolving the contradiction between power saving and reliable traffic delivery.
Solution Approach 2:
The system implements feedback mechanisms where the MME/SGSN monitors the periodic timer status of PSM-capable UEs and communicates availability status to application services via SCEF. This feedback loop enables dynamic adjustment of PSM mode based on actual traffic conditions, allowing the system to switch between power saving and reliable delivery modes as needed.
2Reliability
If the system notifies application services about UE availability to enable reliable data delivery, then traffic delivery success rate improves, but network complexity increases due to additional signaling mechanisms
Solution Approach 1:
The system introduces SCEF (Service Capability Exposure Function) as an intermediary between the MME/SGSN and application services. The SCEF handles the complexity of timer monitoring and availability notification, exposing simplified interfaces to application services while managing the intricate signaling with core network elements. This mediator approach resolves the contradiction by isolating complexity in a dedicated network function.
Solution Approach 2:
The system segments the network functions into distinct modules: MME/SGSN for mobility management and timer monitoring, SCEF for capability exposure and notification management, and application services for data delivery. This segmentation allows each component to handle specific tasks efficiently, reducing overall system complexity while maintaining reliable data delivery through coordinated interactions.
3Productivity
If the system monitors periodic timer expiration to notify UE availability, then traffic delivery timing is optimized, but processing overhead increases
Solution Approach 1:
The system utilizes periodic timer mechanisms already inherent in PSM operation (TAU/RAU timers) to trigger availability notifications. Instead of implementing continuous monitoring, the system leverages these existing periodic events to notify application services when UEs will become available. This approach optimizes traffic delivery timing while minimizing additional processing overhead by reusing established periodic cycles.
Data Source
AI summary
A method is provided in one example embodiment and may include determining that a periodic timer for a user equipment (UE) is about to expire; communicating to an application service, prior to expiration of the periodic timer for the UE, an indication associated with an availability of the UE to receive data from the application service; and communicating the data from the application service to the UE upon receiving the indication. In some cases, the method can include registering, by the application service, to receive the indication from a Mobility Management Entity (MME) or a serving General Packet Radio Service (GPRS) support node (SGSN), wherein the registering is performed via a service capability exposure function (SCEF) in communication with the MME or the SGSN and the application service.