What is 4 G Phones ?

4G I-MODE TECHNOLOGY, JAPAN
In March 2002 NTT DoCoMo announced that trials had begun on the next generation of mobile communications. Dubbed '4G', the new I-mode technology will increase data transmission rates (up to 200 times faster than 2G at 20Mbit/sec). 3G data rates are currently 2Mbit/sec, which is very fast compared to 2G's 9.6Kbit/sec. 4G builds on the 3G standard, although it integrates and unifies the different interfaces (W-CDMA, CDMA2000, EDGE, etc).

4G I-MODE TECHNOLOGY

Since December 2000, NTT DoCoMo and Hewlett-Packard have been jointly developing the software and hardware that make high-speed wireless possible. In October 2001, 3G was successfully rolled-out in Japan, and the new technology will depend on using the established base stations and mobile station equipment. The introduction of 3G technology provided a huge expansion in mobile capacity and bandwidth, and 4G will do the same for the spectrum of broadband communications.

4G TECHNOLOGY CONCERNS

Debate about the new technology has been rife, as the success of 3G has been questioned in both Europe and the USA. One of the main concerns about 4G is that the speed of the frequency suggests that it will experience severe interference from multi-path secondary signals reflecting off other objects. There have been a number of proposed solutions, including using a variable spreading factor (VSF) and orthogonal frequency code division multiplexing (OFCDM).
Other concerns involve cost and the compatibility of various applications, although these are expected to be ironed out in the coming months. For example, FOMA-enabled videophones cannot be used for I-motion music and video links; and the N2002 handset erases parts of the phone's memory if certain websites are accessed. Finally, the cost of I-mode mobile phones is too high for most users, therefore the technology will probably be consigned to corporate use for the foreseeable future.
It is suggested that 4G technologies will give way to 3-D virtual reality and interactive video/ hologram images. 4G will increase interactions between corroborating technologies, so that the smart card in your telephone will automatically pay for goods as you pass a linked payment kiosk - or will tell your car to warm up in the morning, because your phone has noted you leaving the house or setting the alarm.
4G is expected to provide better-than-TV quality images and video-links, although it is likely that forecasts will change as customer demand develops over time. The communications model has developed new versions of HTML, Java, GIF, HTTP and many more. It is expected that new standards will need to be developed for the use in 4G.

JAVA-BASED I-MODE PROGRAMS

Variants of Java-based I-mode programs, include the i ƒ¿ppli, which downloads maps and displays charts of online information. It also enables remote users to receive automatic notifications of weather, traffic, appointments, etc. both online and from a company intranet. The main bonus for users of the software is the additional security encryption, which makes it suitable for e-commerce and mobile banking. This system was developed in conjunction with Sun Microsystems.
It is expected that DoCoMo will roll out the 4G technology platform across Japan in 2006. Other major telecoms operators, such as Ericsson, Lucent and Nokia are researching 4G technology, and in Summer 2002 are expected to begin practical evaluations. These will test data transfer speeds of up to 260 times faster than the current 3G network.