MOBILE TECHNOLOGY
World is moving through various technological advancements and man is pacing with them all. An easiest example is the telecommunication field. From ancient days men used different methods for telecommunication and now we are in the era of mobile technology and internet. The mobile phone which came to catch moving man became all purpose devices in recent days.
Here I am going to explain about the new technology 3G or Third Generation Technology. Till now ,we are familiar with 2G technology which enables us voice communication over air, internet connectivity with EDGE or GPRS connectivity options that provide speed up to maximum of around 65 KB/s. 2G technology is not so much advanced because of its limited bandwidth and transfer rate. But 3G technology when compared with 2G have some advantages. In terms of speed 3G technology is offering a speed of 3MB/s.
3G technology represents a shift from voice oriented communication to multimedia oriented communication and services. Demand for voice services has become the requirement of past days and now it has changed to data or multimedia requirements.
COMPARISON OF 2G AND 3G TECHNOLOGIES
2G TECHNOLOGY
2G technology is based on low band data signaling. One of the popular 2G technology is the GSM-Global Systems for Mobile Communications. It's first implemented in 1991 and using in about 140 countries and around 248 million users around the globe are using it.
Now what's GSM? It's a combination of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA).GSM uses a frequency of 25 MHz of bandwidth with spectrum of 900 MHz FDMA is used to divide the available 25 MHz bandwidth into 124 carriers with 200 kHz frequency. It is then again divided using TDMA into 8 time slots. But later frequency band width of 1.5 GHz is implemented in GSM to increase data capability.
In addition to GSM another technology called Personal Digital Communication (PDC) emerged in Japan. Also the CDMA technology which emerged in North America and it implemented a system called spectrum technology which breaks the speech into small digitized segments and encode to recognize call. 2G technology has some data handling capacity such as fax and sort message service with a speed of 9.6 kB/s. But it's not suitable for data applications like web browsing and multimedia applications.
In order to overcome this drawback new methods like high speed circuit switched data (HSCSD),General packet radio service (GPRS), Enhanced Data Rates for Global Evolution (EDGE) technologies where evolved. It improved data speed up to 57.6 KB/s. This data speed is achieved by 14.4 kB/s data coding and aggregating of four radio channels with time slots of 14.4 kB/s. But all these developments become unsatisfactory because of low bandwidth and speed.HSCSD is the previous step towards the 3G technology.
3G TECHNOLOGY
The 3G technology can be defined as the convergence of existing technologies in 2G. Both terrestrial and satellite components are included in 3G.An important advantage of 3G is that we can integrate existing technologies of 2G such as CD MA,GSM,TDMA into 3G.
This technology uses a Core network and Radio Access Network (RAN).Core network is consisted of packet switching module which includes 3G, SGSNs and GGSNs which has same function as that of GPRS. The circuit switched domain contains 3G MSC for switching of voice calls. Also the access and charge of the services are done through the core network. RAN is entirely different from core network according to its function.
RAN consist of elements like Node B and Radio Network Controllers (RNCs).Node B is equivalent to the base transceiver station in 2G network and RNC is the Base Station Controller in 2G network. It functions as radio source management and helps in switching between circuit switched and packet switched domains. The connection between elements in RAN and between RAN is made possible with the help of lub, lur and lu interfaces. The lu interface is split into circuit switched d and packet switched. The lu interface is based on ATM. Also voice is embedded on virtual networks using AAL2 technology. These switching between 3G SGSNs for data and 3G MSC for voice are made according to the requirement.
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