4G

 Abstract

Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency. The 4g wirelesses uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr. The high performance is achieved by the use of long term channel prediction, in both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for worldwide roaming to access cell anywhere.

Introduction

In 3G systems, making their appearance in late 2002 and in 2003, are designed for voice and paging services, as well as interactive-media use such as teleconferencing, Internet access, and other services. The problem with 3G wireless systems is bandwidth—these systems provide only WAN coverage ranging from 144 kbps (for vehicle mobility applications) to 2 Mbps (for indoor static applications). Segue to 4G, the "next dimension" of wireless communication. The 4g wirelesses use Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless and smart antenna. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr. Frequency band is 2-8 GHz. it gives the ability for worldwide roaming to access cell anywhere.

4G and public safety

There are sweeping changes taking place in transportation and intelligent highways, generally referred to as "Intelligent Transportation Systems" (ITS). ITS is comprised of a number of technologies, including information processing, communications, control, and electronics. Using these technologies with our transportation systems, and allowing first responders access to them, will help prevent - or certainly mitigate - future disasters. Communications, and the cooperation and collaboration it affords, is a key element of any effective disaster response.

Issues

The first issue deals with optimal choice of access technology, or how to be best connected. Given that a user may be offered connectivity from more than one technology at any one time, one has to consider how the terminal and an overlay network choose the radio access technology suitable for services the user is accessing.

Conclusion

The mobile technology though reached only at 2.5G now, 4G offers us to provide with a very efficient and reliable wireless communication system for seamless roaming over various network including Internet, which uses IP network. The 4G systems will be implemented in the coming years, which are a miracle in the field of communication engineering technology.