A major goal toward the 4G Wireless evolution is the providing of pervasive computing environments that can seamlessly and ubiquitously support users in accomplishing their tasks, in accessing information or communicating with other users at anytime, anywhere, and from any device . In this environment, computers get pushed further into background; computing power and network connectivity are embedded in virtually every device to bring computation to users, no matter where they are, or under what circumstances they work. These devices personalize themselves in our presence to find the information or software we need. The new trend is to help users in the tasks of everyday life by exploiting technologies and infrastructures hidden in the environment, without
requiring any major change in the users behavior. This new philosophy is the basis of the Ambient Intelligence concept . The objective of ambient intelligence is the integration of digital devices and networks into the everyday environment, renderingaccessible, through easy and ‘‘natural’’ interactions, a multitude of services and applications. Ambient intelligence places the user at the center of the information society. This view heavily relies on 4G wireless and mobile communications. 4G is all about an integrated, global network, based on anopen systems approach. Integrating different types of wireless networks with wire-line backbone network seamlessly, and convergence of voice, multimedia and data traffic over a single IP-based core network are the main foci of 4G. With the availability of ultra-high bandwidth of up to 100 Mbps, multimedia services can be supported efficiently; ubiquitous computing is enabled with enhanced system mobility and portability support, and location- based services are all expected. Fig. 1 illustrates the networks and components within 4G network architecture.
Figure 1 : 4G networks
Network Integration: 4G networks are touted as hybrid broadband networks that integrate different network topologies and platforms. In Fig. 1 the overlapping of different network boundaries represents the integration of different types of networks in 4G. There are two levels of integration. First is the integration of heterogeneous wireless networks with varying transmission characteristics such as Wireless LAN, WAN, PAN, as well as mobile ad hoc networks. At the second level we find the integration of wireless networks with the fixed network backbone infrastructure, the Internet, and PSTN. Much work remains to enable a seamless integration, for example that can extend IP to support mobile network devices.
All IP Networks: 4G starts with the assumption that future networks will be entirely packet-switched, using protocols evolved from those in use in todays Internet . An all IP-based 4G wireless network has intrinsic advantages over its predecessors. IP is compatible with, and independent of, the actual radio access technology, this means that the core 4G network can be designed and evolves independently from access networks. Using IPbased core network also means the immediate tapping of the rich protocol suites and services already available, for example, voice and data convergence, can be supported by using readily available VoIP set of protocols such as MEGACOP, MGCP, SIP, H.323, SCTP, etc. Finally the converged all-IP wireless core networks will be packet based and support packetized voice and multimedia on top of data. This evolution is expected to greatly simplify the network and to reduce costs for maintaining separate networks, for different traffic types.
Lower Cost and Higher Efficiency: 4G IP-based systems will be cheaper and more efficient than 3G. Firstly, equipment costs are expected to be four to ten times lower than equivalent circuitswitched equipment for 2G and 3G wireless infrastructures. An open converged IP wireless environment further reduces costs for network build-out and maintenance. There will be no need to purchase extra spectrum as 2G/3G spectrum can be reused in 4G, and much of spectrum needed by WLAN and WPAN is public and does not require a license.
Ultra-High Speed and Multimedia Applications: 4G systems aim to provide ultra-high transmission speed of up to 100 Mbps, 50 times faster than those in 3G networks. This leap in provided bandwidth will enable high-bandwidth wireless services, allowing users to watch TV, listen to the music, browse Internet, access business programs, perform real-time video streaming and other multimedia-oriented applications, like E-Commerce, as if sitting in home or office.