3G

What is 3G? :- :- 

"3G" stands for the "third generation" of mobile phones. Basically, a 3G device will provide a huge range of new functionality to your mobile. Up until now, your mobile phone has mainly been used only to carry voice messages, with maybe a bit of SMS text as well. 3G will allow simultaneous transfer of speech, data, text, pictures, audio and video. 

How Do 3G Phones Work?

As technology develops it gets harder and harder to work out what has changed when a new gadget or widget goes on sale. 

This is especially true of mobile phones. The first mobile phones were as bulky portable and attractive as a breeze block. 

Now they are all slinky, shiny and interchangeable. The improvements made to each one only become clear when you start to use them. 

Third-generation, or 3G, networks are going to continue this trend. The phones will look the same as ever but the uses to which they can be put will simply explode. 

How Will 3G Standards Look?

There will be a "family of standards" for 3G, covering new Radio Transmission Technology (RU).A number of proposals for the IMT-2000 3G standard were submitted to the ITU during 1998. Since this time, the industry and standards bodies have coordinated their efforts to harmonize the IMT-2000 candidates and arrive at a smaller set of standards. The Operators Harmonization Group (OHG) - a group of major operators from all parts of the world - has played a key role in this process, and agreed on a set of standards in May 1999.

Access Technologies (FDMA, TDMA, CDMA)  

  

FDMA: Frequency Division Multiple Access (FDMA) is the most common analog system.  It is a technique whereby spectrum is divided up into frequencies and then assigned to users.  With FDMA, only one subscriber at any given time is assigned to a channel.  The channel therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a different channel.  A “full-duplex”  FDMA transmission requires two channels, one for transmitting and the other for receiving.  FDMA has been used for first generation analog systems. 

TDMA: Time Division Multiple Access (TDMA) improves spectrum capacity by splitting each frequency into time slots.  TDMA allows each user to access the entire radio frequency channel for the short period of a call.  Other users share this same frequency channel at different time slots.  The base station continually switches from user to user on the channel.  TDMA is the dominant technology for the second generation mobile cellular networks.  

CDMA:  Code Division Multiple Access is based on “spread” spectrum technology.  Since it is suitable for encrypted transmissions, it has long been used for military purposes.  CDMA increases spectrum capacity by allowing all users to occupy all channels at the same time.  Transmissions are spread over the whole radio band, and each voice or data call are assigned a unique code to differentiate from the other calls carried over the same spectrum.  CDMA allows for a “ soft hand-off” , which means that terminals can communicate with several base stations at the same time. The dominant radio interface for third-generation mobile, or IMT-2000, will be a wideband version of CDMA with three modes (IMT-DS, IMT-MC and IMT-TC).

Abstract

Third generation is the generic term used for the next generation of mobile communications systems. 3G will provide enhanced services to those - such as voice, text and data - predominantly available today.

Video on demand, high speed multimedia and mobile Internet access are just a few of the possibilities for users in the future. 3G Services will expand the possibilities of information and communication.

UMTS is a part of the International Telecommunications Union's (ITU's) 'IMT-2000' vision of a global family of third-generation mobile communications systems.

The technology concepts for third generation systems and 3G services are currently under development industry wide. The global 3G Partnership Project (3GPP), a collaboration of organisations which includes the GSM Association, are committed to bringing us the 3rd Generation mobile systems.

The GSM Association's vision of 3G is based on today's GSM standard, but evolved, extended and enhanced to include an additional radio air interface, better suited for high speed and multimedia data services. This system will enable users of current second generation GSM wireless networks to migrate easily to the new third generation services, with minimal disruption. This new evolved phase of GSM will in addition be an important and integral part of the ITU's IMT-2000 family.

Conclusion

This article offers an introduction to 3G radio transmission technologies and various functionalities of 3G device. A qualitative comparison of mobile wireless technologies that could be viewed simultaneously as substitute and/or complementary paths for evolving to broadband wireless access. The goal of the analysis is to explore the future of wireless access and to speculate on the likely success and possible interactions between the mobile technologies in the future. Successful implementation, adoption, and overall acceptance of the 3G wireless networks depends largely on the ability of these new mobile networks to interface and inter-work with the existing 2G and legacy networks currently deployed worldwide.3G is a class apart from other older generations. It would blur the traditional boundaries of technologies- computing, communication and consumer devices. Let’s hope that 3G technology will come up worldwide, providing users with global roaming.