The second generation mobile communication systems, such as GSM, enabled voice traffic to go wireless. The number of mobile phones with 80% penetration exceeds the number of landline phones in countries with the most advanced wireless market. However, with the development of mobile communications, mobile users and Internet users are increasing dramatically. People expect that next generation mobile communication systems can provide larger capacity and support mobile multimedia services. Besides providing real-time speech service, next generation mobile communication systems are required to support non real-time services such as low/high rate data, pictures etc. The data handling capabilities of second generation systems are limited, now the second generation mobile communication systems are able to provide high bit rate services that enable high quality images and video to be transmitted and received, and to provide access to the web with high data rates.Heterogeneous services have different quality of service (QoS) requirements, for example, the requirements of time delay, error bit rate,... |