SIP-Based Vertical Handoff Between WWANs and WLANs 1 WLAN-UMTS - PowerPoint PPT Presentation

SIP-Based Vertical Handoff Between WWANs and WLANs 1

WLAN-UMTS Interworking Architecture  Loosely coupled integration architecture • WWANs and WLANs are connected through the Internet, and each is an independent IP wireless access domain.  Tightly coupled integration architecture • WLANs are incorporated into WWANs as part of its radio access subsystem. 2

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SIP Terminal Mobility  Pre-call mobility • Re- registers its new IP address with its “home” by sending a REGISTER message  Mid-call mobility • Sends an INVITE message about the terminal’s new IP address and updated session parameters 4

WLAN-to-UMTS Vertical Handoff 5

UMTS-to-WLAN Vertical Handoff 6

Analysis of Handoff Delay  There are two types of delays associated with the handoff process • Wireless component delay: the delay introduced by the error-prone wireless links in the UMTS and WLAN access networks for the correct transmission of the associated handoff messages • Processing delay: the queueing delay due to the load in the computing entities, such as the CSCF servers, SIP servers, and even the mobile host in the signaling path 7

Analysis of Handoff Delay  Let the handoff delay during mid-call terminal mobility be D Handoff , which can be divided into • The delay during the attachment procedures • The delay due to location update using the SIP INVITE message.  For handoff to UMTS networks, •  For handoff to WLAN • 8

Analysis of Handoff Delay  D SIP-UMTS and D SIP-WLAN are the transmission delays of SIP location update • • 9

Analysis of Handoff Delay 10

Analysis of Handoff Delay 11