WLAN-UMTS Handoff Pre-Authentication and Buffering
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Solution Overview
Problem
The existing handoff methods between WLAN and UMTS networks experience significant delays and packet loss due to the separation of L2 and L3 handoffs, which are not flexible and do not adequately address authentication processes, leading to inefficiencies in interworking configurations.
Innovation Solution
A method that performs pre-registration and pre-authentication processes before handoff, using a gateway GPRS support node (GGSN) and serving GPRS support node (SGSN) to manage authentication and encryption key distribution, and buffers packets to ensure seamless handoff from a WLAN network to a UMTS network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-registration handoff method is used to reduce handoff delay, then handoff speed is improved, but authentication process is not adequately addressed causing packet loss in WLAN-UMTS interworking
Solution Approach 1:
The patent performs authentication processes in advance before the actual handoff occurs. Specifically, when a mobile node is camped on WLAN, the network performs UMTS authentication procedures ahead of time so that when handoff to UMTS is triggered, the authentication is already complete, eliminating authentication delays during handoff while ensuring reliable security verification
Solution Approach 2:
The patent separates the authentication process from the handoff execution process. The authentication is performed as a preliminary independent phase when conditions permit (while camped on WLAN), and the handoff execution becomes a simpler L2 handoff operation, resolving the contradiction by decoupling these two functions
2Productivity
If L2 and L3 handoffs are separated to improve handoff performance, then handoff efficiency is improved, but flexibility in handling authentication processes deteriorates
Solution Approach 1:
The patent performs L3 handoff (Mobile IP registration) and authentication processes in advance while the mobile node is still camped on WLAN, before the actual L2 handoff is triggered. This preliminary execution of L3 procedures maintains high handoff efficiency while providing the flexibility to complete authentication beforehand, adapting to WLAN-UMTS interworking requirements
Solution Approach 2:
The patent makes the handoff process dynamic by allowing L3 handoff and authentication to be performed at different times based on network conditions. The system can flexibly execute L3 procedures preliminarily when camped on WLAN, or handle them during handoff depending on specific scenarios, thereby maintaining both efficiency and adaptability
3Device complexity
If conventional handoff scheme is used to maintain simplicity, then system complexity is reduced, but handoff delay and packet loss increase in WLAN-UMTS interworking
Solution Approach 1:
The patent introduces preliminary L3 handoff and authentication execution when the mobile node is camped on WLAN, before actual handoff is needed. This approach reduces handoff delay and packet loss by pre-completing critical procedures, while maintaining relatively simple system architecture by building upon existing Mobile IP and authentication frameworks rather than creating entirely new complex mechanisms
Data Source
AI summary
A seamless handoff system and method reduces delay and packet loss during handoff of user equipment (UE) from a Wireless Local Area Network (WLAN) network to a Universal Mobile Telecommunication System (UMTS) network. The handoff system and method performs pre-registration and pre-authentication processes before the occurrence of a handoff, buffers packets being delivered to a UE during a handoff period, and forwards the buffered packets to the UE after completion of the handoff, thereby reducing packet loss that can occur during handoff.