Ongoing standardization effort on 3G cellular systems in 3GPP (UMTS) is based on GPRS core network and promises a global standard for systems capable of offering ubiquitous access to Internet for mobile users. Considered radio access systems (FDD CDMA, TDD CDMA, and EDGE) are optimized for robust mobile use. However, there are alternative relatively high-rate radio interfaces being standardized for WLAN (IEEE 802.11 and HIPER-LAN/2) which are capable of delivering significantly higher data rates to static or semi-static terminals with much less overhead. Also WPANs (BLUETOOTH, IEEE 802.15), which will be present in virtually every mobile handset in the near future, are offering low cost and considerable access data rate and thus are very attractive for interworking scenarios. The prospect of using these interfaces as alternative RANs in the modular UMTS architecture is very promising. Additionally, the recent inclusion of M-IP in the UMTS R99 standard opens the way for IF-level interfacing to the core network. This article offers an overview into WLAN-Cellular interworking. A brief overview of GPRS, UMTS cellular architectures and relevant WLAN standards is given. Possible interworking architectures are presented.
