Siemens IEEE802.11 - Manual (Page 76)

WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 76 © Siemens, 2002
PSTN
PLMN access
PLMN core
VLR
HSS
AUC
SGSN
SCPLNP
IN
GGS
N
TDM / ATM / IP
MSCS MSCS
BTS BSC
BTS
Node B
Node B
RNC
internet
wlan local access network
WLAN – UMTS Interworking:
Ancient approach: ‘tight coupling’
WLAN as just another radio access technology of UMTS
n
All UMTS services become available over WLAN.
but:
n
PLMN is burdened with high bandwidth WLAN traffic.
n
Wi-Fi does not provide all the functionality needed (QoS, security).