Multi-SIM UE Capability Signaling in 5G Networks
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Solution Overview
Problem
Current 5G wireless communication systems lack support for multi-SIM capabilities, leading to issues such as rejected or silently discarded service requests from multi-SIM user equipment (UE) due to unawareness of UE's multi-SIM capability by 5G-RAN and core network entities.
Innovation Solution
The proposed solution involves methods and apparatus for a UE with multiple SIMs to transmit information about its multi-SIM capability to nodes in the Radio Access Network (RAN) via RRC messages, enabling the selection of an Access and Mobility Management Function (AMF) that supports multi-SIM capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-SIM UE transmits capability information to RAN node, then service acceptance and functionality are improved, but device complexity and signaling overhead increase
Solution Approach 1:
The UE transmits its multi-SIM capability information to the RAN node during the initial registration process or capability exchange phase, before any service requests are made. This preliminary action ensures that the network is aware of the multi-SIM capability in advance, allowing proper routing to AMF instances that support multi-SIM operations, thereby preventing service rejections later.
Solution Approach 2:
The RAN node acts as an intermediary that receives the multi-SIM capability information from the UE and uses this information to make intelligent routing decisions. The RAN node mediates between the UE and the core network by selecting appropriate AMF instances that are configured to handle multi-SIM scenarios, thus enabling multi-SIM functionality without requiring changes to the UE's internal complexity.
2Reliability
If RAN node routes to AMF supporting multi-SIM, then service request acceptance improves, but network complexity increases
Solution Approach 1:
Different AMF instances are assigned different qualities or capabilities - some AMF instances are specifically configured to support multi-SIM operations while others handle standard single-SIM operations. The RAN node uses the received capability information to route multi-SIM UEs to AMF instances with the appropriate quality (multi-SIM support), ensuring reliable service acceptance without requiring all network entities to be complex multi-SIM aware.
Solution Approach 2:
The system introduces a new parameter (multi-SIM capability indicator) in the capability information exchanged between UE and RAN. This parameter change enables the RAN node to differentiate between multi-SIM and single-SIM UEs, allowing it to select appropriate AMF instances based on this parameter. This simple parameter addition triggers a cascade of appropriate routing decisions without fundamentally changing the complexity of existing network entities.
Data Source
AI summary
Many commercially deployed devices support more than one SIM cards. Support for multi-USIM is currently handled in an implementation-specific manner without any support from 3GPP specifications. With the increased complexity of 5G-capable UEs and with growing demand for multi-USIM devices in the market, it becomes important to consider system enhancements that would allow for more efficient solution involving required support to UE from 5G core and 5G-RAN.