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3G

In this article, we shall tell you all about 3G. Firstly what is 3G? Well, it is basically the next generation of wireless communications technology, the name has caught on pretty fast. The concept covers everything from the technology to the branding of mobile communication devices. 3G aims to deliver the capability of much higher data rates to mobile communications devices over a large geographical area. In some areas, there could be data rates up to 2 Mbits / second. 3G also aims to unify the wireless devices all around the world, so that a user from UK could travel all around Europe and perhaps even the US, and still be able to use the same, high-speed data links, without any fault.

3G means a packet switched suite of protocols, basically a technology that had originally been developed for the Internet. It uses techniques like Code Division Multiple Access (which was originally developed for the military), and it allows efficient, toast, and secure communications over the wireless medium. To end-users like us, 3G means fast browsing of the World Wide Web, file transfers and emailing, even video phoning and video conferencing from their mobile phones, laptops, or PDAs. 3G aims to give coverage all over Europe, USA, China, Japan – basically the whole world, with seamless integration between all over these countries.

Even the concept of 3G is relatively new, it is nevertheless catching on quite fast, and more and more wireless technology companies are working on developing devices with 3G capabilities – like Siemens, Nokia, and Sony Ericsson. Following 3G is 4G, a technology which is expected to truly integrate the Internet as well as mobile telecommunications.

Much like the Internet, 3G is a packet switched technology. There are some fundamental principles of Radio Transmission Technologies (RTTs) one needs to understand to figure out how 3G works.

First comes Simplex and Duplex. In simplex transmission information only flows one way at a time, because only one frequency is used for communication. A good example of this is walkie-talkies. With a walkie-talkie set, only one person can talk to the other at any given time, for the other person to transmit, they must wait until the other person has stopped. Whereas in duplex transmission, two data transmissions can be sent at any given time – this is true for mobile phones, which allows both people to speak at the same time, without any delay.  FDD uses several frequencies, one for the upstream (signals going from phone to the base station), and one for the downstream (from the base station to the phone), also a guard band is needed.

Then there is Time Division Duplex (TDD), which uses time, and not frequency, to do the duplexing, this helps to save frequencies. It switches the signals very rapidly – first the upstream transmits, then the downstream transmits, and this is a continuous cycle which happens quickly, so that it seems like the upstream and downstream and constantly connected. As with FDD, the end product is the same, but fewer frequencies are used, some sort of guard is also needed.

And finally, there comes symmetric and asymmetric transmission. The former is where the upstream and downstream are the same data rate or same speed. Your voice on mobile phones use symmetric transmission, as the data needed to transmit your voice is the same as receiving another person’s. however, when it comes to Internet surfing and video broadcasts, much more downstream bandwidth is needed, as one would mostly be receiving data. So basically only requests are sent upstream, for example, when you click on a link. An asymmetric connection is ADSL broadband, the A stands for Asymmetric Broadband, usually has 256Kbps of upstream, and 512+ Kbps on the downstream bandwidth. The 3G network has a hierarchy of different sized cells – a macro cell (biggest of three areas, coverage is approximately the size of a city), a micro cell (coverage of a city centre), and a pico cell (smallest coverage, perhaps a hotel, or airport, this is often also known as a hotspot).

The reason for these divisions is on the basis of simpler, shorter-range communications which are not only faster, but also allow for a higher amount of users. So now you know why a Pico cell, or a hotspot, is located to busy areas like airport or coffee shops. TDD, on the other hand, isn’t too good at transmitting long distances – mainly because of the delay. TDD uses time to duplex signals on to the same frequency, and the further a mobile phone is away from the base station, the longer it takes a signal to travel – because there is a delay, and because of the switching between time slots cannot happen too quickly, there is a decrease in usable bandwidth. So in the future of 3G, we need convergence, of the phone networks, so that the world can be united with a wireless technology that is compatible everywhere across the world.

3G, in a nutshell, is basically one of the latest technologies that have been incorporated into mobile devices today. 3G gives people the opportunity to access information and data from any place, at any time. It is also known as UMTS (Universal Mobile Telecommunications System), and is described by Cellular (2004) as being a generic name for a set of mobile technologies which make up a host of high-tech infrastructure networks, handsets, switches, base stations, and other equipment. Basically the network allows cell phones to offer not only high-speed Internet access, but also data, video and CD-quality music services.

The first launch of 3G phones was in October 2001 in Japan. Then they were introduced to South Africa in December 2004. The design of the phone was such that users could view pictures of the person they were talking to, surf the Internet, watch movies and listen to music – all on their handsets.

So how is 3G different from GPRS? Well, 3G data services are one step higher than GPRS. 3G has consistently faster data rates, which allows one to work faster. 3G can offer speeds up to 384 kilobits per second, which is up to 7 times faster than a standard dial-up connection.