Depending on the level of the reader 4G can be defined in different ways. In simplest terms, 4G is the next generation of wireless networks that will replace 3G networks sometimes in future. In another context, 4G is simply an initiative by academic R&D labs to move beyond the limitations and problems of 3G which is having trouble getting deployed and meeting its promised performance and throughput. In reality, as of first half of 2002, 4G is a conceptual framework for or a discussion point to address future needs of a universal high speed wireless network that will interface with wire line backbone network seamlessly.
Here's something we don't see often: a wireless technology that could actually arrive earlier than predicted. Fourth-generation (4G) cellular services, intended to provide mobile data at rates of 100Mbits/sec or more, were originally scheduled for 2010. Some cell phone companies have moved the target up to 2006, while rival wireless systems could bring similar bandwidth to a few fortunate networkers a lot sooner.
Two aspects characterize the resulting fourth generation wireless network scenario (4G). First, the network consists of a collection of heterogeneous networks that provide end-to-end wireless technology over wireless. In addition, it is a "stupid network" scenario, where the network only provides packet transport, and therefore it is an "operator-less" network with respect to services. This scenario also implies that the mobile users and devices that participate in communication over 4G must become smarter, i.e., they must be able to respond to a wide range of events.
4G Network
Recently the introduction of the third generation mobile networks has just been taking place which holds out the possibilities what have never been seen before. Every mobile generation created something new and more valuable for the users in comparison with previous networks and this will be the case also with the appearance of the fourth generation.
As time and the technology progresses, people get used to having access to information at any time, independently of the presence of any cables. Moreover, people want to have continuous high quality services and, at the same time, are unaware of how they will get it and where they are going next. Hence, they need a functioning mobile infrastructure capable of handling high amounts of data. Current mobile standards (the so called "2G", second generation, networks) can be used to transfer data at very limited speed. The recently implementing generation, 3G, will offer better data transfer capabilities, but its speed is still insufficient for many desired applications like video conferencing. Only the next generation, "4G", the fourth generation, will offer data transfer at fully acceptable rate.
However, since the 4G will need to use higher frequencies, it also provides much smaller coverage area per base station. This means, in particular, that while users could enjoy continuous video conferencing, a more complicated infrastructure of service providers has to be set up. Some effort has been done to elaborate on the 4G technical solutions but less on the economical side of this problem.
4G will provide different features like fully packet switching networks, higher bandwidths for providing multimedia services at cheaper rates, higher bit rates approx 100 mega bits per second, very high network security etc. It will have interactive multimedia services such as wireless internet and teleconferencing.
The 4G technology was predicted to become applicable around 2010 but due to so many features and facilities the researchers had put their efforts and by investing $30 billion the technology will be available by 2006, something which has never happened before.
Comparision Between 1G, 2G, 3G and 4G
Before knowing about the advancements in 4G let us have a look at the previous generations, their features and drawbacks.
The first operational cellular communication system was deployed in the Norway in 1981 and was followed by similar systems in the US and UK. These first generation systems provided voice transmissions only, using frequencies around 900 MHz. These 1G systems used analog modulation and provide only for voice transmission. The 1G adapted cellular structure. The roaming function was missing in 1G. These 1G systems which provided low quality voice services, were very limited in capacity and did not extend across geographic areas.
Digital second generation (2G) systems were developed in Europe in early 1990s (mainly GSM, based on TDMA technology) and the US (mainly IS95, based on CDMA technology) to provide better voice (audio) quality, higher capacity, global roaming capability as well as lower power consumption. 2G systems also offer support for simple non-voice services like SMS. However, different 2G technologies do not interoperate. There are also difficulties with roaming between GSM and IS95 countries. In addition, the low bit rate of 2G systems (9.6kbps for GSM) cannot meet subscriber demands for new and faster non-voice services on the move. In spite of this due to the intensive developments in microelectronics second generation was quite successful. The weight of the terminals (handset) considerably decreased (from 1 kilogram to few grams). Due to their more user-friendly structure, the appearance of the SIM card and their services based on circuit switched digital communication millions of user opted for this successful system and chose a GSM terminal. The roaming function has been solved as well, the clients can use also the services of other providers and services have become available even in abroad in about the same quality and range, too.
So-called ‘2.5G’ systems recently introduced, enhance the data capacity of GSM and mitigate some of its limitations. It allows cell phones to surf the web but in a very limited way.
Third generation (3G) systems aim to solve the problems encountered with 2G, by promising global roaming across 3G standards, as well as support for multimedia applications. The new third generation (3G) cellular services known as Universal Mobile Telecommunications System (UMTS) or IMT-2000 will sustain higher data rates still and opens the door to many internet style applications. 3G Systems achieve cellular re-use by using a technique called CDMA (Code Division Multiple Access). With the advent of 3G systems, and its accompanying mobile applications and services, mobile devices will become more than just a hand phone or a basic electronic organiser. Hybrid devices will appear in the near future, supporting traditional voice, video streaming and downloads, as well as Internet and Intranet access. 3G’s high bit rate capabilities will allow the convergence of value-added data and voice services on the same mobile device. This will dramatically change the way people communicate, work and carry out their daily lives.
