19-05-2012, 04:29 PM
3g technology
3G Seminar.doc (Size: 144.5 KB / Downloads: 28)
What is 3G?
3G refers to the next generation of wireless communications technology; it is a ‘catch all’ name which encompasses everything from the technology to the branding of mobile communication devices.
The aim of 3G (third generation) is to deliver the capability of much higher data rates to mobile communications devices over a large geographical area. Data rates of up to 2megabits per second will be capable in some areas.It is also the aim of 3G to unify the wireless devices the world over, so a user from the UK, can travel Europe, and the US, and use the same, highspeed data links, seamlessly as they travel the globe.
3G is a packet switched suite of protocols, a technology which was originally developed for the internet, it also uses techniques such as Code Division Multiple Access (originally developed by the military) to allow efficient, fast, and secure communications over the wireless medium.
To the end user, 3G means fast World Wide Web browsing, file transfers, emailing, even video phoning and video conferencing from their mobile phone, PDA, or laptop. With coverage over all of Europe, the USA, China, Japan, and the rest of the world, with seamless integration between all of these countries and more.
Although 3G is relatively an infant, the technology is growing fast, with more and more wireless technology companies developing devices with 3G capabilities, such as Nokia, Siemens and Sony Ericsson.
On the horizon is 4G, a technology which will truly integrate the internet, and mobile telecommunications.
Evolution towards 3G
Being called 3G, or third generation, there is, inevitably, a first and second generation.
1G refers to the original analogue mobile phones, which resembled a brick. They were large, and very heavy, due to the weight of the battery, they were also very expensive. However, they paved the way for something that was soon to become a revolution in the technological world, phones would soon start to be smaller, lighter, cheaper, and better. Operating time increased while battery weight dropped, this was due to advancements in battery technology, as well as circuit design which allowed for much lower power consumption.
2G saw the birth of the digital mobile phone, and a standard which is the greatest success story in the history of the mobile phone to date. The Global System for Mobile Communications (GSM) is a standard that unified Europe’s mobile phone technologies, it allows one phone to be used throughout Western Europe. Using TDMA (Time division multiple access), the GSM standard allowed millions of users throughout Europe to travel freely and still be able to use there phone. Although Europe enjoyed a unified standard, in America, three standards still exist, from three different companies. Because of this mobile communications haven’t become nearly as popular in the States, as they have done in Europe.2G worked well for voice communications, it provided data rates of up to 9.6Kbps, good enough for voice, but no where near enough for bandwidth demanding modern day media, such as Video and file transfers. Something which the world was screaming out for, and to provide this, 3G was developed.
Due to the nature of 3G, and its incredible complexity and expensive, the move from 2G to 3G wasn’t going to happen over night, so the 2.5G standard was developed.
The 2.5G standard had a major technically different feature compared to its predecessor, it used Packet Switching technology to transmit data. The General Packet Radio Service (GPRS) replaced GSM as the 2.5G standard. GPRS actually overlays a packet switched technology onto the original GSM circuit switched network. Data rates of 2.5G can reach 50kbps, some may think this is a waste of time, and service provides should have gone straight to the goal and implemented 3G, however, the 2.5G standard is a much needed step, as it gives service providers experience of running packet switched networks, and charging on a data bases, rather than a time basis.
Other than GPRS, another standard called EDGE is another upgrade option from GSM, and is three times faster with a maximum transfer rate of 150Kbps as opposed to GPRS’s 50Kbps. EDGE also can be an upgrade from TDMA networks, so some American operators may go this route.
How does 3G work?
3G is a packet switched technology, much like the internet. There are some basic principles of Radio Transmission Technologies (RTT’s) we need to understand before we can understand how 3G works, these are:
Simplex & Duplex, TDD & FDD, Symmetric & Asymmetric transmission, TDMA & FDMA, Circuit switching & packet switching and 3G geographical cells.
Simplex and Duplex
In a simplex transmission, information can only flow one way at one time, this is because there is only one frequency being used to communicate on. The easiest way of explaining this is to use walkie-talkies as an example. With a set of walkie-talkies, 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.
In a duplex transmission, two data transmissions can be sent at any one time, this is how mobile phones work, it allows both people to speak at the same time, without any delay. If more than two data transmissions can happen at any one time, this is called multiplex.
TDD and FDD
Up until the recent developments of mobile phones, FDD (frequency division duplex) was used, this is where several frequencies are used, one for the upstream (signals going from the phone to the base station), and one for the downstream (the opposite, from the base station to the phone). A “guard band” is also needed, which sits in between the frequencies to separate them and provide isolation.
Although FDD works, it is very wasteful, as it uses several frequencies in total, and not to there full potential. This is why TDD was developed.
3G Seminar.doc (Size: 144.5 KB / Downloads: 28)
What is 3G?
3G refers to the next generation of wireless communications technology; it is a ‘catch all’ name which encompasses everything from the technology to the branding of mobile communication devices.
The aim of 3G (third generation) is to deliver the capability of much higher data rates to mobile communications devices over a large geographical area. Data rates of up to 2megabits per second will be capable in some areas.It is also the aim of 3G to unify the wireless devices the world over, so a user from the UK, can travel Europe, and the US, and use the same, highspeed data links, seamlessly as they travel the globe.
3G is a packet switched suite of protocols, a technology which was originally developed for the internet, it also uses techniques such as Code Division Multiple Access (originally developed by the military) to allow efficient, fast, and secure communications over the wireless medium.
To the end user, 3G means fast World Wide Web browsing, file transfers, emailing, even video phoning and video conferencing from their mobile phone, PDA, or laptop. With coverage over all of Europe, the USA, China, Japan, and the rest of the world, with seamless integration between all of these countries and more.
Although 3G is relatively an infant, the technology is growing fast, with more and more wireless technology companies developing devices with 3G capabilities, such as Nokia, Siemens and Sony Ericsson.
On the horizon is 4G, a technology which will truly integrate the internet, and mobile telecommunications.
Evolution towards 3G
Being called 3G, or third generation, there is, inevitably, a first and second generation.
1G refers to the original analogue mobile phones, which resembled a brick. They were large, and very heavy, due to the weight of the battery, they were also very expensive. However, they paved the way for something that was soon to become a revolution in the technological world, phones would soon start to be smaller, lighter, cheaper, and better. Operating time increased while battery weight dropped, this was due to advancements in battery technology, as well as circuit design which allowed for much lower power consumption.
2G saw the birth of the digital mobile phone, and a standard which is the greatest success story in the history of the mobile phone to date. The Global System for Mobile Communications (GSM) is a standard that unified Europe’s mobile phone technologies, it allows one phone to be used throughout Western Europe. Using TDMA (Time division multiple access), the GSM standard allowed millions of users throughout Europe to travel freely and still be able to use there phone. Although Europe enjoyed a unified standard, in America, three standards still exist, from three different companies. Because of this mobile communications haven’t become nearly as popular in the States, as they have done in Europe.2G worked well for voice communications, it provided data rates of up to 9.6Kbps, good enough for voice, but no where near enough for bandwidth demanding modern day media, such as Video and file transfers. Something which the world was screaming out for, and to provide this, 3G was developed.
Due to the nature of 3G, and its incredible complexity and expensive, the move from 2G to 3G wasn’t going to happen over night, so the 2.5G standard was developed.
The 2.5G standard had a major technically different feature compared to its predecessor, it used Packet Switching technology to transmit data. The General Packet Radio Service (GPRS) replaced GSM as the 2.5G standard. GPRS actually overlays a packet switched technology onto the original GSM circuit switched network. Data rates of 2.5G can reach 50kbps, some may think this is a waste of time, and service provides should have gone straight to the goal and implemented 3G, however, the 2.5G standard is a much needed step, as it gives service providers experience of running packet switched networks, and charging on a data bases, rather than a time basis.
Other than GPRS, another standard called EDGE is another upgrade option from GSM, and is three times faster with a maximum transfer rate of 150Kbps as opposed to GPRS’s 50Kbps. EDGE also can be an upgrade from TDMA networks, so some American operators may go this route.
How does 3G work?
3G is a packet switched technology, much like the internet. There are some basic principles of Radio Transmission Technologies (RTT’s) we need to understand before we can understand how 3G works, these are:
Simplex & Duplex, TDD & FDD, Symmetric & Asymmetric transmission, TDMA & FDMA, Circuit switching & packet switching and 3G geographical cells.
Simplex and Duplex
In a simplex transmission, information can only flow one way at one time, this is because there is only one frequency being used to communicate on. The easiest way of explaining this is to use walkie-talkies as an example. With a set of walkie-talkies, 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.
In a duplex transmission, two data transmissions can be sent at any one time, this is how mobile phones work, it allows both people to speak at the same time, without any delay. If more than two data transmissions can happen at any one time, this is called multiplex.
TDD and FDD
Up until the recent developments of mobile phones, FDD (frequency division duplex) was used, this is where several frequencies are used, one for the upstream (signals going from the phone to the base station), and one for the downstream (the opposite, from the base station to the phone). A “guard band” is also needed, which sits in between the frequencies to separate them and provide isolation.
Although FDD works, it is very wasteful, as it uses several frequencies in total, and not to there full potential. This is why TDD was developed.