27th September 2020

What is in a G

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We all know that in order to get data on your phone or on nifty little gadgets like a Mifi we’ll use something like ‘3G’ or ‘4G’. Mobile operators and some Internet Service providers use those terms abundantly in their marketing and I guess they all assume that we know what those terms mean. Or at the least, they hope that we get impressed by them enough to buy their service.

So let’s explore what these G’s actually mean, but without getting too technical.

On the face of it, it is simple. The ‘G’ stands for ‘Generation’ in mobile telephony. Advances in technology often move in spurts and each large spurt or leap could be called a generation. In that light many of us are now using technologies of the fourth generation, or 4G in short. However, there is no inventor or engineer who will call 4G. They have much more complicated abbreviations and acronyms to denote many more small steps within each generation. Since those do not look well in 1.5m high lettering on a billboard the marketing folks came up with the G’s. It is always nice to say that your competitor is still on 3G while you are now offering 4G, a whole generation newer. Later is faster and therefore better, isn’t it?

1G

The very first mobile call with a handset was made in 1973 (a Motorola engineer calling his competitor at Bell to brag that they were first). That first generation of mobile telephony was not very far removed from the common walkie-talkies. Based on open analog VHF frequencies for the handset connection it was easy to listen in and to disrupt. The handsets were very large and heavy and perhaps more suitable as car phone then as a proper mobile phone that you could carry around.

Data was in theory possible using something called GPRS, but not routinely implemented on the phones. Basic GPRS in principle works on any radio link, even on ultra-long distance HF radio systems, but is, to our current standards, extremely slow.

2G

With the advent of digital systems we enter the second generation. GSM telephony (in Europe), CDMA (in the Americas) and TDMA phones and networks became available. Handsets were getting smaller as battery technology scrambled to produce a better output to weight ratio. Our old and virtually unbreakable Nokia 3310’s were from that generation. Many still work after more than 15 years! Try that with your iPhone 7 or Sony Xperia, not to mention the extinct Samsung Note 7.

2G phones did not come standard with data capabilities. Some could do GPRS, but since GPRS uses the voice link to send data much as a fax does you cannot do that at the same time as a voice call. Its extension Edge fixed that and is still in use here and there. Some handsets could feed the data with a serial cable to a laptop (tethering but without USB), but on the phone itself there usually was no browser and certainly no apps as we know them now. That only came later with smart phone operating systems like Apple’s iOS, Windows Mobile, Nokia’s Sybian and of course Google’s Android derived from Linux. But by then we are already in third generation territory.

3G

3G was developed because, with the growth of the Internet, data was becoming an important product for a larger public. Volumes were going up and there was a growing demand for higher speeds. Phone operating systems were now capable of actually doing something with that data instead of just passing it on and phones were quickly becoming small hand-held computers. Even the cheapest smart phones could do 3G which means that with a bundle you can do Skype, WhatsApp, Youtube and browse the world.

This is also the time of long and unpronounceable acronyms. Edge is still around under 3G (some say it is really 2.9G) and there are things like HSPDA, HSDA+. They are all names for extensions of the original 3G data standards. Some are a good improvement and deliver speeds that are approaching the lower speeds of 4G. Zambia’s Airtel markets it as ‘3.75G’. It gets the message across, I guess. Literally.

4G

In the 4th Generation the divider between regular fixed Internet and mobile Internet is disappearing. It is an official standard now and has many advanced tricks built-in to improve performance (OFDM, MIMO and more). And it is IP-based meaning at some level it works the same as a good old ethernet network.
4G started with the later versions of WiMax (often called by it’s official IEEE name 802.16e) for home Internet. Handsets came on the market that could connect to those WiMax transmitters. The system would allow mobile connections with tower-to-tower hand-overs without dropping connection. The latter sounds trivial but is essential to a good mobile experience. The higher versions of WiMax have been installed on towers in Zambia first by iConnect and later by others. Now there is LTE, already being deployed by MTN and Vodafone. Many of us have either a phone that connects directly to an LTE base station or by Wifi to a mobile gadget called a Myfi that picks up data using LTE and transmits it as Wifi so more devices can get connected.

One problem with 4G and the growing demand for data use is that there is a physical limitation to the bits that you can push per second through a MHz of bandwidth. OK, I know this is getting technical, but see it as a dual-carriage highway. A trucks can carry only  a limited amount of boxes (data) and the road has only two lanes so can accommodate only two trucks side-by-side. The speed of the truck is set and fixed: the speed of the waves in the air being the determining factor. The only real way to increase data transport is to increase the number of lanes so you can have more trucks side by side. And that is a problem because everyone and his uncle wants to have a lane for themselves. Just consider what all travels over radio: mobile phones, Wifi, terrestrial TV, satellite TV, radio, walkie-talkies for army, air force, police, ambulance, the fire brigade, aviation and many many others. The radio spectrum is crowded and all services are competing for space. It is like the land next to the existing highway is already occupied so they can’t add more lanes unless someone gets evicted. Any land that happens to get vacant, like the frequencies for the old analog terrestrial TV will be soon, is now being eyed by data providers to increase their throughput.

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5G

And now 5G is creeping up. We should have seen it coming. However, what it is exactly isn’t clear yet. The experts are still debating about the technical requirements to call something ‘5G’ and the standards have not been written yet. What is clear that the speeds are higher, that different frequency bands will be used and that the Internet of Things (IoT) will be important in its list of applications. But that is a topic for a different article.

Author: Erik Schoute is a consultant with Amsterzam Limited