LIPA SIPTO Paging via S1-U Tunnel Encapsulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication network technologies face challenges in supporting downlink paging for Local IP Access (LIPA) and Selected IP Traffic Offload (SIPTO) services, particularly in scenarios where the UE is in idle mode, due to the need for additional core network interfaces and changes in existing protocols, which complicates the routing of traffic and paging mechanisms.
Innovation Solution
A method and network device that monitor UE traffic to store IP addresses for default EPS bearers, utilize existing tunnels for downlink datagram transmission, and implement a local paging agent function to activate paging procedures without requiring additional core network interfaces, by encapsulating datagrams in S1-U tunnels and routing them through S5 interfaces, ensuring seamless paging even when UE is in idle mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional core network interfaces are terminated for LIPA/SIPTO service management, then LIPA/SIPTO services can be supported, but device complexity and network complexity increase
Solution Approach 1:
The S1-MME interface is made multi-functional by enabling it to carry both traditional EPC control signaling and LIPA/SIPTO specific control signaling. The paging agent function is integrated into existing network elements (MME or HeNB), allowing these elements to perform both their traditional functions and the additional LIPA/SIPTO paging trigger function, thereby avoiding the need for separate dedicated interfaces.
2Reliability
If standard paging procedures are used for LIPA traffic, then protocol integrity is maintained, but paging cannot be triggered since LIPA traffic does not traverse via Core Network nodes
Solution Approach 1:
A paging agent function is introduced as an intermediary component that can be deployed either in the MME or in the HeNB. This paging agent intercepts downlink data packets destined for LIPA UEs, extracts the necessary information, and generates appropriate paging commands using existing S1AP protocols. This approach maintains protocol integrity while enabling paging functionality for LIPA traffic without requiring full protocol rewrites.
3Ease of manufacture
If L-GW is collocated with HeNB for simple LIPA access, then deployment simplicity is improved, but sensitive User Context must be stored in untrusted customer premises
Solution Approach 1:
The critical security function of User Context storage is extracted from the collocated L-GW at the HeNB and relocated to the trusted core network (MME or HSS). The collocated L-GW retains only the minimal functions needed for local packet routing and paging trigger initiation, while sensitive user data remains in the secure core network environment. This separation maintains deployment simplicity while ensuring security.
Data Source
AI summary
A method for supporting downlink paging for LIPA or SIPTO while a first UE has been moved to an idle mode may include monitoring UE traffic while the first UE is in the active state and storing a UE IP address for a default EPS bearer of the first UE in a node and in a gateway for LIPA or SIPTO service. A downlink datagram for paging activation is sent towards the first UE over an existing tunnel, wherein the tunnel was established for a second UE being in an active state, wherein the tunnel may be established for the second UE or any other UE served by the same node and the same gateway, and activating a paging procedure by receiving the downlink datagram via the tunnel in a gateway, which gateway is serving the first UE for the default EPS bearer service of the first UE.