The Third-Generation (3G) wireless technologies offer wireless web, SMS, MMS, EDGE, WCDMA, GPRS etc. 4G is a packet switched technology, uses bandwidth much more efficiently, allowing each user's packets to compete for available bandwidth. It solves the non-standardization problems associated with 3G. Data transfer rate will be 20 to 100 Mbps, which is 10 to 50 times than 3G and 10-20 times faster than ADSL. Operating frequency range will be 3 to 10 GHz and the IPv6 protocol will be used. In this paper, fundamentals of 4G and their various proposed architectures are explained. In India it can be used to network rural and urban areas, reduce cost of communication, flourish educational activities, facilitate research and development, faster internet connectivity, more cellular options, real time information systems, crisis management, Tele-medicines and many more. The present 3G networks need not to be discarded, and can be used in conjunction with 4G technology. There are various architectures proposed that can be used to deploy 4G.
4G Wireless Networks
The fourth-generation wireless (4G) technology implements designs that will take the wireless telecommunication industry beyond 2010. The infrastructure of the 4G will function on top of the current existing CDMA, GSM and TDMA. It extends the 3G capabilities These technical opportunities strengthen the user mobility and encourage the deployment of the mobile technologies for the development of various (mobile) applications providing information, orientation (routing) and other helpful services.
Fig1. INCREMENTAL PROGRESS OF WIRELESS TECHNOLOGY
It will deliver superior quality video and data, in addition to voice. It also solves the non-standardization problems associated with 3G networks for voice, video and data transmission. The data transfer rate is 20 to 100 Mbps, which will be 10 to 50 times those offered by 3G links and 10-20 times faster than standard ADSL (Asymmetric Digital Subscriber Line) services. The operating frequency ranges between 3 to 10 GHz and the IPV6 protocol used will be used. High-definition television programming through wireless broadband connections, Internet-based multi-channel video and higher mobile Internet will become a reality. The Defense Advanced Research Projects Agency (DARPA) in the US originally conceived of 4G.
2. Need of 4G:
•3G performances insufficient to meet high performance future needs. •Multiple incompatible standards. Global mobility and service portability required. •Need for hybrid networks for both WLAN and cellular network design. •Technology to utilize newly found modulation methods.
•Need for All IP network with converged voice and data capability. •Wider bandwidth.
3.1 End-to-End Internet Protocol (IP):. It will provide access through a collection of radio interfaces, seamless roaming/handover and the best-connected service, combining multiple radio access interfaces (such as WLAN, Bluetooth and GPRS) into a single network that subscribers may use. It allows any mobile device to seamlessly roam over different wireless technologies automatically, using the best connection available for the intended use. Users will have access to different services, increased coverage, the convenience of a single device, one bill with reduced total access cost, and more reliable wireless access even with the failure or loss of one or more networks. 3.2 Peer-to-Peer networks: In this system, every device is both a transceiver and a router/repeater for other devices in the network, elimination of a single node does not disable the network. 4G can be defined as "wireless ad hoc peer-to-peer networking."
4. Significance of 4G
In 4G networks, users joining the network add mobile routers to the network infrastructure. Network capacity and coverage is dynamically shifted to accommodate changing user patterns. Wherever the concentration of people is more in one...