Second-generation (2G) mobile systems were very successful in the previous decade. Their success prompted the development of third generation (3G) mobile systems. While 2G systems such as GSM, IS-95, and cdmaOne were designed to carry speech and low-bit-rate data, 3G systems were designed to provide higher-data-rate services. During the evolution from 2G to 3G, a range of wireless systems, including GPRS, IMT-2000, Bluetooth, WLAN, and HiperLAN, have been developed. With the rapid development of wireless communication networks, it is expected that fourth generation mobile systems will be launched within decades. 4G mobile systems focus on seamlessly integrating the existing wireless technologies including GSM, wireless LAN, and Bluetooth. This contrasts with 3G, which merely focuses on developing new standards and hardware. 4G systems will support comprehensive and personalized services, providing stable system performance and quality of service. However migrating current systems to 4G presents enormous challenges. In this seminar these challenges are discussed under the headings of mobile station, system and service aspects. Proposed solutions to the research problems in each aspect will also be examined.