Mobility Management Entity Packet Switched SMS Implementation
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Solution Overview
Problem
Current technologies lack a specific solution for implementing Packet Switched (PS) Short Message Service (SMS) in the Evolved Packet System (EPS), particularly in scenarios involving LTE in-band roaming, where SMS services are not effectively supported through the PS domain.
Innovation Solution
A method and system where a mobility management entity, upon receiving an SMS-only indication from user equipment, enquires subscription information from a home subscriber server and, if supported, transmits SMS through the PS domain using PS non-access stratum signaling, or falls back to the Circuit Switched domain or SGs interface based on subscription and capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional CS domain SMS is used in EPS, then SMS service can be provided, but the packet architecture advantage is lost and network resource efficiency deteriorates
Solution Approach 1:
The patent replaces the circuit switched domain SMS mechanism with a packet switched domain SMS mechanism. Specifically, it uses PS NAS signaling to transmit SMS messages through the packet core network (MME, HSS, SGSN, GGSN) instead of the traditional circuit switched path (MSC, VLR, GMSC). This substitution enables EPS to leverage its packet architecture for SMS delivery, improving network resource efficiency while maintaining service availability through proper protocol design.
2Adaptability or versatility
If PS-only SMS is implemented in EPS, then packet architecture is fully utilized, but compatibility with existing networks deteriorates
Solution Approach 1:
The patent implements dynamic domain selection for SMS delivery based on subscription information and network capabilities. The MME determines whether to use PS domain or fall back to CS domain based on: (1) UE subscription data from HSS indicating PS-only or PS-preferred mode, (2) Network capability flags, and (3) Roaming status. This dynamic approach allows the system to adapt to different network configurations and subscription types, maintaining both architectural flexibility and network compatibility simultaneously.
Solution Approach 2:
The patent introduces the MME as an intermediary entity that mediates between the UE and the SMS delivery system. The MME queries HSS for subscription information, determines the appropriate delivery domain (PS or CS), and routes SMS messages accordingly. This intermediary mechanism enables seamless transition between different network domains and maintains compatibility with both PS-only and CS networks while implementing flexible packet architecture utilization.
3Reliability
If CSFB is used for SMS in EPS, then SMS service is maintained, but system complexity increases
Solution Approach 1:
The patent extracts the SMS delivery function from the circuit switched domain and places it directly within the packet switched domain. Instead of using CSFB which requires fallback to CS domain through multiple interfaces (Gs, MGc), the invention implements PS SMS directly through packet core network elements (MME, HSS, SGSN, GGSN) using PS NAS signaling. This extraction simplifies the architecture by eliminating the need for complex CS-PS interworking mechanisms while maintaining SMS service continuity.
Data Source
AI summary
A method for implementing a Packet Switched domain (PS) short message service (SMS) includes: after receiving request message containing an SMS-only indication transmitted by a user equipment, a mobility management entity enquiring subscription information of the user equipment from a home subscriber server, and receiving the subscription information of the user equipment returned by the home subscriber server; and when the mobility management entity supports the PS SMS and the subscription information supports the PS SMS, the mobility management entity transmitting request acceptance message to the user equipment, receiving and transmitting an SMS between the mobility management entity and the user equipment through a Packet Switched domain. Embodiments of the present document further provide a system for implementing a PS SMS and a user equipment. By means of the scheme of the present document, the PS SMS can be implemented in an EPS system.