What are 1G, 2G, 3G, etc., mobile networks?
Every day we see and hear commercials about 3G from various mobile operators. However, not everyone knows what these numbers and letters mean. Nowadays, 3G is most commonly associated with mobile internet. In reality though, everything is not that simple.
What is a mobile network?
Mobile network is a network of radio stations that provide a two-way radio communication with the user in their operating region. Each station works over a small area in the shape of a honeycomb cell. This is where the “cellular network” term comes from. A few of these stations can cover quite a large area. This allows the network users to always stay connected, even if they are moving.
What does the “G” mean?
The capital “G” in 1G, 2G, 3G, etc. stands for “generation”. This means that all mobile networks are divided into different generations. In this article we would like to talk a little bit about the history of mobile networks development.
It is a common opinion that 1G originated in the 1980s, although the “official” date when the 1st generation mobile network was introduced is actually the 3rd of April, 1973. On this day, the head of Motorola mobile communication department, Martin Cooper, called the head of AT&T Bell Labs research department, Joel Engel, while standing in the middle of a street. Therefore, it’s not surprising that Motorola and AT&T Bell Labs became the two pioneers of the mobile industry.
At that time the following communication standards existed:
- AMPS (Advanced Mobile Phone Service) in the USA, Canada, Central and South America, Australia.
- TACS (Total Access Communications System) in England, Italy, Spain, Austria, Ireland, Japan.
- NMT (Nordic Mobile Telephone) – the so called “Scandinavian standard”, also used in a number of other countries, not just the Scandinavian ones.
- C-450 for Germany and Portugal.
- RTMS (Radio Telephone Mobile System) in Italy only.
- Radiocom 2000 in France only.
It would be incorrect to call these communications mobile, since the first mobile communication standards were in fact analog. The standards mentioned above were only used for sending voice messages. Modems already existed at that time, but wireless communications were often distorted and influenced by various noises. The data transfer speed was quite low while the price for this service was rather high.
Analog communication was not perfect either. Among a variety of disadvantages the main one can be easily pointed out – the ability of other users to listen in on your conversation. If you had a chance to use telecommunications of that time you surely had the case where you could hear somebody else speaking while being on the phone. The signal was disappearing constantly and calling abroad was a nightmare experience.
Basically, each country had their own system which was incompatible with systems of other countries. This is why there was a need to create a single system with high bandwidth and large coverage area. The main goal was to set up a system where every incoming call was to be transferred to a specific phone, no matter where the user was located.
2G and 2.5G
In 1982, a European Conference of Postal and Telecommunications Administrations (CEPT) formed a special group for researching and developing a wireless communications system for general purpose - GSM (from French Groupe Spécial Mobile). This is how the second generation (2G) was born. In 1989, European Telecommunications Standards Institute (ETSI) took over responsibilities of the CEPT. In the beginning, GSM only worked in countries that were part of the ETSI. In time, however, it spread to other regions as well, like Eastern Europe, Asia, Africa and the Middle East. After this, GSM began to stand for Global Special Mobile.
The first 2G networks started to appear in 1991. This was a so called digital boom. The main difference between 1G and 2G was digital data transmission method. All telephone conversations were encrypted with digital code. The beloved SMS (Short Message Service) also appeared.
At the same time, the USA and Europe were moving in different directions. Europe was using the GSM standard while most of the US networks were built on the D-AMPS standard (Digital AMPS). After a while though, they created their own version of GSM – GSM1900.
After the Internet had appeared and started to gain popularity, a special protocol called WAP (Wireless Application Protocol) was created specifically for mobile networks. This protocol allowed having wireless Internet access from mobile devices.
Communication security was considered to be the main advantage of 2G. Because every call was encrypted it was almost impossible to interfere or listen in on someone’s conversation.
With each year, the need for internet access from a mobile phone increased. This was a key factor for creating a new 2,5G generation – a sort of “bridge”, or transition between 2G and 3G. After the creation of 2,5G a new feature was added to the mobile communication standards – a data packet transfer service called GPRS (General Packet Radio Service). GSM networks used the technology called EDGE (Enhanced Data-rates for GSM Evolution).
Data packet service increased the maximum data transfer speed for mobile devices from 9.6 kbit/s to 384 kbit/s.
GPRS and EDGE technologies could not be called 2G as they were a lot faster, but at the same time they were not fast enough to be 3G. Very often GPRS was referred to as 2,5G and EDGE – as 2,75G.
Now we are finally getting to the good part – the well-known and highly advertised 3G. The main difference between 2G and 3G is pretty straightforward. Because of the number of 3G frequencies it is possible to simultaneously transfer packets of data and have a channel connection. Despite this, 3G is not something incredibly new or original. It has been around for quite a while but up until mid-1980s it was kept secret and used only by the military and special services.
3G combines three digital wireless communication standards – FOMA, UMTS and CDMA200.
FOMA is used in Japan while CDMA200 is used in the US. UMTS standard was created as a transition step from GSM.
3G has clearly defined requirements for data transfer speed:
- 2014 kbit/s – for users that are not moving;
- 384 kbit/s – for users moving at speeds up to 3 km/h;
- 144 kbit/s – for users moving at speeds up to 120 km/h.
This list was approved by the International Telecommunication Union.
Thanks to the HSDPA+ protocol, UMTS standard allows transferring data at 42 Mbit/s. This type of channel decreases the time necessary to load web pages or downloading files. It is also sufficient enough to perform voice and video Internet calls, watch videos and use various multimedia services even when you are travelling in a plane. These high speeds were still not sufficient to be 4th generation though, as the International Telecommunication Union certified completely different requirements for 4G.
The first and the most important 4G requirement is the data transfer speed. The requirement was set in 2008:
- 100 Mbit/s – for users moving at higher speeds (train or car)
- 1 Gbit/s – for users moving at lower speed (walking).
On the contrary to its predecessor, 4G networks don’t use voice channels and work only with digital data. This means that calls are transformed into VoIP format. This, in due time, can cause the classic cellular communication to be completely abandoned in favor of internet telephony.
4G consists of two standards at the moment – WiMAX and LTE. WiMAX (Worldwide Interoperability for Microwave Access) is an evolved version of Wi-Fi with a high coverage area. LTE (Long Term Evolution) is another branch that has evolved from GSM.
In the beginning, both of these standards were not fulfilling the 4G requirements of 1Gbit/s speed. After some time they were significantly improved, until in 2010 the International Telecommunications Union officially approved two technologies to comply with the IMT-Advanced requirements:LTE-Advanced WirelessMAN-Advanced
It is possible that very soon 4G will replace the wired Internet, as it is a lot simpler to put a single LTE station instead of setting up an entire web of cables.
Although 5G is currently in the stage of development, some achievements have already been made. At the end of October, 2015, a South Korean company SK Telecom declared they wanted to be the first 5G provider. They managed to transfer data at 19.1 Gbit/s, which is several times higher than the existing 4G.
Verizon, a company from the US, is planning to be the first to test and introduce a commercial version of 5G. They are hoping to provide speeds 30-50 times higher than LTE, which is currently available in the USA. An Australian company Telstra is also planning to enter the 5G market in 2020.
The 5th generation will mostly be used in metropolitan and special industrial areas.
Some even think that television will also move to mobile networks after some time, and users will be able to, for example, watch 3D movies of very high quality online.