How 5G is different – explained without jargon

5G has hit the headlines through the banning of Huawei’s 5G network technology in several countries. But what is 5G? And how is it different from what we have already?


5G stands for the 5th generation of cellular mobile network technologies.

Cellular systems enable radio frequencies to be re-used for different phone calls in adjacent ‘cells’, each with its own radio transmission mast. This enables the network to support many more phone calls within large cities, within the same limited, allocated radio frequency spectrum. As your phone is moved from one cell to another, the network “hands over” your current phone call from one cell to the next, fairly seamlessly with modern networks. But many of us will remember experiencing call dropouts in the early networks.

The first cellular mobile phone networks, called AMPS (retrospectively numbered 1G), were introduced in 1987 in Australia. 1G was the last of the analogue mobile technologies, and it only supported voice services. ‘Analogue’ describes signals that are similar to the waveform of the human voice and other natural sounds, in contrast to ‘digital’ signals, in which numbers are used to encode the original waveform or image or message. The 1G phones were initially as large as house bricks, and expensive, but then became smaller and cheaper.

Generations 2G to 5G are all digital. Each successive generation has been introduced at roughly a decade apart. With each new generation, the manufacturers have sought to provide better performance, new services, and cost improvements. The phones for the European standard (GSM) 2G network, introduced here in 1993 using the new 04 dialling prefix, were much lighter and more compact than before. Unlike 1G phones, they supported Small Message Services (SMS), now known as text messages, in addition to digitally encrypting your phone calls.

However, in rural areas GSM did not have the longer range which AMPS provided, and there was political resistance to the replacement of AMPS by GSM. As a result, in 1999 Telstra launched a second 2G network called CDMA which matched AMPS’ long distance performance while using the same spectrum as AMPS. AMPS was closed down in 2000, and CDMA lasted in some regions until 2012.

Making major improvements to mobile technologies has required moving to new radio frequencies each time, to obtain additional bandwidths. ‘Bandwidth’ in the digital world means the maximum data rate that can be transmitted via a connection, most commonly measured in megabits per second (Mbps) or gigabits per second (Gbps). Thus your Internet connection might be rated as having a downstream bandwidth of 25 Mbps and an upstream bandwidth of 10 Mbps. (Whether it achieves those rated speeds is another matter.)

3G technology, launched here in 2003, supported higher data rates, good enough to support high quality voice and the first video calls. It also supported a lot of useful data services, such as computer to computer communication and Global Positioning System (GPS) location-based applications.

Later releases of 3G supported low Mbps data rates – fast enough for Internet access to images. These higher speeds stimulated the integration of high definition digital cameras into phones, as the images they take can be transmitted in seconds, rather than previously over minutes – which risked failure through call interruption. 3G’s capabilities were vital for the launch of the iPhone in 2007 and the first Android phones after that.

4G technology, introduced here in 2011, supports higher speed broadband access to the Internet, and also multi-media text messages, with the promise of 100 Mbps peak data rates. It enables the transmission of multi-megapixel photos, video clips and video streaming to and from portable laptops, tablets and smart phones. And it is a boon for those without NBN access, if you are based within a 4G radio footprint.

All new smartphones sold in Australia are currently 4G compatible, including those sold as 5G phones. The most advanced 4G networks can in fact support up to 1Gbps data rates, although you would need to be sharing a 4G cell with very few other users to achieve that peak rate.

5G technology offers some very significant differences. 2G, 3G and 4G were basically cellular digital mobile services offering larger user bandwidths with each new generation. 5G does that too – with a capability of up to 20 Gbps downstream in certain niche applications. But by using a greater range of alternative frequencies, 5G offers a much larger range of applications and performance features. 5G smartphones are designed to lock in to all the alternative 5G frequencies, as well as those used in 4G (and 3G too in some models).

What are 5G’s new features? What is not at all widely known is that 5G promises to be many times cheaper than 4G for the network owners (the “carriers”) per gigabyte in delivering data (via its new frequencies, and using superior signal processing technology in 5G phones). To my mind, that is the greatest commercial driver for the introduction of 5G – all the rest is icing on the cake. But there are layers and layers of icing!

Firstly, 5G generally offers its customers several hundred Mbps downstream – up to 10 Gbps or more if you are one of only a few in a cell using the mmWave spectrum (above 24 GHz). This is a lot more bandwidth than most NBN customers can currently get, so there will be competition between the technologies, especially in the NBN access networks using Fibre to the Node or fixed radio connections. Those using NBN satellite connections are based in remote, thinly populated areas, and are unlikely to get 5G for many years, if ever.

Secondly, a full 5G implementation (not just a mixture of 4G and 5G to support a call) will reduce end-to-end network delay (known in the trade as latency) down to a target of 1 ms, as compared to an average of 50 ms with 4G. This will support the critically small latencies needed for remote control of driverless moving vehicles, for example.

Thirdly, 5G has been designed to support tens of billions of sensors worldwide, mostly operating at very low data rates: the so-called ‘Internet of Things’. On some conservative estimates, there will be more than 20 billion devices connected to the Internet by the end of this year alone: CCTV cameras, traffic lights, parking meters, all classes of vehicles, home security systems, public lighting, soil and irrigation sensors, weather and air quality monitors, etc. etc. 5G will provide a cheap way of connecting them.

Fourthly, 5G has the capability of supporting software-defined “slices” through an entire network. Each slice provides a protected, private network capability, incapable of being accessed by those connected to the public network or by users of other slices. This has many potential applications, including emergency services, which currently use proprietary private radio networks which often do not interwork across State boundaries.

And fifthly, 5G can be used as “fixed radio” line-of-sight links to support much superior data rates than, for example, the NBN’s Fibre to the Node or its current Fixed Wireless links. Optus has very recently released a self-installable 5G modem which can support 300 Mbps speeds (and above) delivered by a line-of-sight radio link from an Optus 5G tower, for just $70 per month. This promises to be a major threat to NBN Co’s revenues in its lower bandwidth access areas.

In Australia 5G networks are being rolled out by Telstra, Optus and TPG Vodafone. The rollouts started in 2019 and will continue until at least the mid-2020s before reaching most populated areas of the country. Existing 3G radio base stations are being converted to 4G/5G stations, 4G base stations are being converted to 4G/5G, and new 4G/5G base stations are being installed ay a great rate.

Telstra has made a huge bet on 5G. In late 2016 it revealed it was investing $3 billion on transforming its networks, platforms and processes so as to become the Australian leader in 5G by 2022. In June 2018 it announced its intention in the medium term to sell off of its entire traditional fixed network wholesale business and its retail fixed line services, ­ no longer profitable enough in the NBN era. In effect, Telstra’s Board is ‘betting the company’ on the potential of 5G. And hot on its heels in 5G national network rollouts are Optus and TPG Vodafone – the latter doubly delayed, first by having to abandon its planned use of Huawei infrastructure and second by having to win a legal battle to achieve its merger.

In summary, 5G is truly a major advance on 4G in all it can potentially do and support, including the vast Internet of Things. Little wonder that Telstra has been ‘betting the company’ on 5G, and has already extended its coverage to over 46 cities across Australia. Optus and TPG Vodafone are in hot pursuit. All will be bidding for additional radio spectrum in 2021 to extend their 5G capabilities further.


Peter Gerrand spent over 20 years as an engineer in the telecommunications industry, before becoming a professor of telecommunications at first RMIT and then the University of Melbourne. He has served as an independent expert advisor to the ACCC and to the former telecommunications industry regulator AUSTEL. These days he is an honorary professorial fellow at the University of Melbourne, and an active member of the NBN Futures Group.  Website bio:

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