The fourth generation (4G) mobile communications, aims at providing various services such as high-speed data services and IP-based access seamlessly over heterogeneous wireless networks. Vertical handoff optimization is one of the most intriguing issues in realizing the ubiquitous characteristics of the 4G networks. To solve this problem, many vertical handoff procedures and architectures have been proposed for various interfacing technologies e.g. WLAN, GSM, GPRS, and CDMA. These handoff mechanisms are either based on mobile IP or IPv6 technology. However, there seem to be no effective development so far in enhancing the overall end-to-end throughput, and economical profitability for heterogeneous wireless environments. In this thesis, various vertical handoff mechanisms are discussed, and system architecture for vertical handoff in location-aware heterogeneous wireless networks is proposed. The proposed architecture enables the mobile node to prepare for approaching vertical handoffs and wake-up a hotspot interface. The issues of mobility and geo-location information are considered in proportion to usability, advantages and limitations.
