The common feature of the next generation wireless technologies will be the convergence of multimedia services such as speech, audio, video, image, and data. This implies that a future wireless terminal, by guaranteeing high-speed data, will be able to connect to different networks in order to support various services: switched traffic, IP data packets and broadband streaming services such as video. The development of wireless terminals with generic protocols and multiple-physical layers or software-defined radio interfaces is expected to allow users to seamlessly switch access between existing and future standards. . | Introduction The common feature of the next generation wireless technologies will be the convergence of multimedia services such as speech audio video image and data. This implies that a future wireless terminal by guaranteeing high-speed data will be able to connect to different networks in order to support various services switched traffic IP data packets and broadband streaming services such as video. The development of wireless terminals with generic protocols and multiple-physical layers or software-defined radio interfaces is expected to allow users to seamlessly switch access between existing and future standards. The rapid increase in the number of wireless mobile terminal subscribers which currently exceeds 1 billion users highlights the importance of wireless communications in this new millennium. This revolution in the information society has been happening especially in Europe through a continuous evolution of emerging standards and products by keeping a seamless strategy for the choice of solutions and parameters. The adaptation of wireless technologies to the user s rapidly changing demands has been one of the main drivers of this revolution. Therefore the worldwide wireless access system is and will continue to be characterized by a heterogeneous multitude of standards and systems. This plethora of wireless communication systems is not limited to cellular mobile telecommunication systems such as GSM IS-95 D-AMPS PDC UMTS or cdma2000 but also includes wireless local area networks WLANs . HIPERLAN 2 IEEE b and Bluetooth and wireless local loops WLL . HIPERMAN HIPERACCESS and IEEE as well as broadcast systems such as digital audio broadcasting DAB and digital video broadcasting DVB . These trends have accelerated since the beginning of the 1990s with the replacement of the first generation analog mobile networks by the current 2nd generation 2G systems GSM IS-95 D-AMPS and PDC which opened the door for a fully digitized network. .
