Technology never ever ceases to move ahead and that is no different in the case of mobile phones. 3G stands for the third generation cellular phone communication technology. The concept of 3G Technology, once considered to be a far-fetched idea, has become a reality today with more and more users across the world taking to it like never before. Though the technology can be run only on handsets that specifically support 3G, its popularity is growing worldwide at a rapid rate. In fact, with each passing day, cell phone companies are coming up with new and improved models of 3G enabled handsets.
Evolution and success of 3G Technology
The 3G Technology was first devised with a focus on research and analytics. The project began in 1992, and by 1999, the International Telecommunication Union (ITU) approved five radio interfaces. Instances were already there wherein compatible and suitable extensions were ceded to pre-existing 2G networks with frequency allocation. Hence, International Mobile Telecommunications (2000), also known as the IMT 2000 or third generation or 3G Technology, is a telecommunication service which fulfills the specifications laid down by the International Telecommunication Union.
3G Technology is a one of most recent radio transmission technologies (RTTs). To completely understand the modern technology we have to know what 3G Technology standards and 3G Technology spectrums are.
The third generation technology (3G Technology) digital mobile multimedia offering broadband mobile communications with voice, video, graphics, audio and other information.
The mobile communications industry has evolved in four stages, and correspondingly four generations of mobile phones have emerged thus far. Each one has provided more flexibility and usability than the previous ones.
(1G Technology) Analog point helped to make voice calls inside one’s country without roaming facilities.
(2G Technology) Digital mobile phone used fax, data and messaging capabilities as well as voice telephone service in many countries offering worldwide roaming.
(3G Technology) Multimedia services add high speed data transfer to mobile devices, allowing new video, audio and other applications (including Internet services) through mobile phones.
- With 3G Technology, the information is split into separate but related packets before being transmitted and reassembled at the receiving end. Packet switched data formats are much more common than their circuit switched counter parts.
- The World Wide Web is becoming a primary communications interface. People access the Internet for entertainment services and information collection. The intranet for accessing enterprise information and connecting with colleagues and the and the extranet for accessing customer and supplier
Speeds of up to 2 Mb per second (MBPS) can be achieved with 3G Technology. The data transmission rates will depend upon the environment, the call is being made in. However, only indoors and in stationary environments these types of data rates will be available. For high mobility, data rates of on 144kbps are expected to be available.
Applications of 3G Technology
3G Technology facilitate several new applications that have not previously been readily available over mobile networks due to limitations in data transmission speeds.
These applications range from web browsing to file transfer to home automation (the ability to remotely access and control in-house appliances and machines).
Because of the bandwidth increase, this application works even more easily available with 3G than they were previously with interim technologies.
Concepts we have to know how does 3G work
- Simplex vs. Duplex
- TDD vs. FDD
- Symmetric vs. Asymmetric transmission.
- TDMA vs. CDMA
- Circuit Switching v Packet Switching
- Simplex vs. Duplex:
When people use the walkie-talkie radio to communicate, only one person can talk at a time (the person doing the talking has to press a button). This is because walkie-talkie radios only used one communication frequency-a form of communication known as Simplex.
Simplex: using you walkie-talkie you have two push a button to talk one way. Of course, this is how mobile phones work. Mobile phones allow simultaneous two way transfer of data – a situation known as duplex (if more than two data streams can be transmitted, it is called Multiplex):
The communication channel from the base station to the mobile device is called downlink, and the communication from the mobile device back to the base station is called the uplink.
How can duplex communication be achieved? Well, there are two possible methods which we will now consider: TDD and FDD.
- TDD Vs. FDD
Wireless duplexing has been traditionally implemented by dedicating to separate frequency bands: one band for the uplink and one band for the downlink (this arrangement of frequency bands is called (paired spectrum). This technique is called frequency division duplex, or FDD. The two bands are separated by a “guard band” which provides isolation of the two signals:
FDD: uses paired spectrum – one frequency band for the uplink and one frequency band for the downlink.
TDD: duplex communications can also be achieved in time rather than by frequency. In this approach, the uplink and downlink operate on the same frequency, but they are switched very rapidly one moment the channel is sending the uplink signal, the next moment the channel is sending the downlink signal. Because the switching is performed very rapidly this is called Time division duplex or TDD. TDD required a guard time instead of the guard band between transmit and receive streams.
- Symmetric transmission vs. Asymmetric transmission:
Data transmission is symmetric if the data in the downlink and the data are in the uplink is transmitted at the same data rate. This will probably be the case for voice transmission-the same amount of data is sent both ways.
A symmetric applications, E.g., the Internet-384K bps for the downlink and 64 K bps for the uplink
- TDMA vs. CDMA:
We have considered how a mobile phone can send and receive calls at the same time (via an uplink and a downlink). Now we will examine how many users can be multiplexed into the same channel (i.e., shared the channel) without getting interference from other users, a capability called the multiple access. For 3G Technology, there are basically two competing technologies to achieve Multiple Access
TDMA and CDMA:
TDMA is Time division multiple access. It works by dividing a single radio frequency into many small timeslots. Each caller is assigned a specific timeslot for transmission.
CDMA is code division multiple access. CDMA works by giving each user a new code. The receiver has knowledge of sender unique code, and is therefore able to extract the correct signal no matter what the frequency is.
- Circuit switching vs. Packet Switching:
Traditional connections for voice communication require a physical path connecting the users in the two ends of the line, and that path stays open until the conversation ends. This kind of connection is called Circuit Switching.
Most modern networking technology is radically different from this traditional model because it uses a packet data.
- Chopped into pieces.
- Given a destination address.
- Mixed with other data from other sources.
- Transmitted over a line with all the other data.
- Reconstituted at the other end.
Packet data was originally developed as the technology behind the INTERNET.
How does 3G work
Macro cells, Micro Cells and Pico Cells
The 3G Technology might be divided up in hierarchical fashion:
- Macro cell- The area of largest coverage, e.g., an entire city.
- Micro Cell- The area of intermediate coverage, e.g., a city centre.
- Pico cell- The area of smallest coverage, e.g., a “hotspot” in a hotel or airport.
Smaller regions (shorter ranges) allow higher user density and faster transmission rates. This is why they are called “hotspots”.
- TDD mode doesn’t allow long range transmission (the delays incurred would cause interference between the uplink and the downlink).
- For this reason, TDD mode can only be used in environments where the propagation delay is small (Pico cells).
- As we explained in the previous section on symmetric transmission vs. asymmetric transmission.
- TDD mode is highly efficient for transmission of internet data in Pico cells.
- In the old days, when all phones were fixed rather than mobile, making a call involved establishing a direct electrical connection between your handset and the one you were calling.
- The same happens with GSM mobiles, but instead of setting up a dedicated circuit, a small portion of the airwaves are reserved for your call.
- This is a really bad way of dividing the available airwaves because it means that the spaces and pauses in speech get the same priority as the words.
- 3G Technology networks change all this. Instead of reserving airspace each conversation is chopped up into packets, each one of which is labeled with a code denoting which dialogue it is from.
New Flavors’- high speeds:
- This radical change means 3G Technology mobile networks can support lots more subscribers and let them download data much faster. On current GSM networks data chugs around at 9.6 kilobits per second (kbps).
- By contrast the upper limit for 3G Technology networks is 2 megabits per second if you are standing still and 384kbps for those on the move.
- These are maximum rates and possible speed will fall as more people download data in any particular cell. It is possible that at peak times phone users will be luck to do better that the 56kbps possible over a fixed phone.
- Using packets of information to carry voice and data also means that your phone is effectively always connected to the network.
- This will mean a huge change in the way that you pay for you phone. Mobile operators will have to stop charging on the basis of talk time and move to a model based on the packets you download or a single charge per month covering anything and everything you do.
- The day of 3G Technology may be dawning but it will be a long time before the sun sets on our existing mobile phones.
3G Technology enabled cell phones have revolutionized the cellular phone industry almost all across the globe. Armed with the advanced technology, data can now be easily transferred at great speeds when compared to other normal cellular phones. That’s not all. The technology plays a very crucial role in providing prompt services to work in a trouble-free manner as regards 3G Technology mobile phones. These phones have amassed special importance in recent times as a mobile phone is no more used merely to make calls and send SMS. Cell phones, today, are vastly used for accessing the internet and downloading content.
Importance of 3G mobile phones
Internet browsing and Bluetooth connectivity require sophisticated and high-speed technology. Such criteria can only be fulfilled by 3G Technology cell phones that offer high-speed internet connections. A 3G mobile phone gives the user unbelievable data transfer speeds and enhanced internet connectivity for meeting all their expectation. 3G Technology phones were mostly inspired by the 2.5G cell phones that comprise GPRS technology. GPRS, or general packet radio services, provides efficient and good internet speeds, thereby enabling faster browsing. GPRS was in high demand till 3G Technology was introduced.
3G cell phones are likely to be in high demand for several years to come. They are expected to stand the tests of time providing users with lightning-fast internet speeds and prompt connectivity. The 3G Technology would enable the user to send and receive photos, audio and video via MMS, besides instant uploading of recorded video to the internet.
While the technology is still in its nascent stage, more and more people are switching over to 3G Technology as they don’t mind paying a little extra for better services. Despite the prices for availing 3G Technology being considerably higher when compared to 2G, it’s expected that the same would come down once the operators roll out the technology all across the world, as was in the case of 2G.