Let’s start off with a brief explanation of the different mobile signal Generations – what’s 2G, 3G and 4G? 2G / 3G and 4G are simply the names of standards that have evolved over the years. Prior to all of these mobile phone signals were analogue but it was quickly replaced with digital transmission signals which provided the extra benefit of better quality calls, better signal penetration and data services such as SMS, MMS and IP (internet protocol).

• 2G was introduced in the 90’s and was comprised of two different standards – CDMA and TDMA. Here, we use the GSM standard which is based on TDMA, and 80% of subscribers around the world typically use GSM. It is a very old standard that is to be retired, however many countries still use the 2G standard and your phone will often fall back to 2G when 3G or 4G connections aren’t available. On some older phones, you can see a ‘GPRS’ icon or just a single ‘G’. This means you’re using the older 2G network.

2G services have completely shut down in Australia. Older mobile phones using 2G will not operate on any Australian network, and many devices that use GSM for communication, such as alarms, GPS trackers, weather stations etc. will also lose connectivity to the network.

• 3G is an upgrade over the existing 2G GSM networks, with some extensions and improvements, and was relatively easy to adopt as existing 2G towers could be upgraded to provide WCDMA coverage. 3G is a large improvement over 2G because it now not only allows for faster data transmission, but also allowing for simultaneous use of data and voice at the same time. 3G has undergone many changes and upgrades since it’s inception and now has the following standards implemented:
• Evolved High Speed Packet Access, or HSPA+, allows for the phone to receive calls when receiving data over the network, as well as a data transmission rate of 42mb/sec in Australia. This upgrade was termed “3.5g” because of it’s theoretical max speeds of 168Mbps (but this was never delivered here)
• Enhanced Data rates for GSM Evolution (EDGE) — is a backwards compatible standard design to work with GSM. You can sometimes see your phone fall back in to EDGE mode when you are out of range of a 3G tower — this is denoted by a capital “E” on your cell network indicator. In this mode, you might not be able to access data services, but can still make or receive phone calls via the GSM network.

There are three 3G network frequencies currently in use:

1. 850MHz (B5) – Telstra, Vodafone
2. 900MHz (B8) – Optus, Vodafone
3. 2100MHz (B1) – Telstra, Optus, Vodafone

• Purchasing Guide: Most modern smartphones will support all three 3G frequencies. However, many low-cost phones (often sold with a prepaid SIM bundle) including “feature phones” and smartwatches, may not support all three, as a consequence of cost cutting or other technical reasons.

3G usage is on the decline globally. Telstra has announced plans to shut down 3G networks by June 2024.

• LTE is the next-step of the evolution of UMTS (3G) and HSDPA (3.5G) is a complete redesign and simplification of 3G network architecture resulting in a marked reduction in transfer latency.
• LTE, shorthand for Long Term Evolution was the predecessor before the mass adoption of true 4G. It indicates a service that provided transfer speeds of 20 to 50mbps, speeds that were 10 times faster than 3G. It was launched in 2011 and for marketing purposes, it was called 4G even though it didn't meet the International Telecommunication Union's minimum standards to be considered a 4G service. True 4G services became available after carriers upgraded the network several years later.
• 4GX or 4G LTE can provide speeds of anywhere between 100mbps to 1gbps, depending on various factors and how the network was built.

The vast majority of calls and data transmissions in Australia now relies on 4G LTE networks and with new features such as carrier aggregation introduced in 2014, devices can connect multiple cellular frequencies at once to increase the data rate (download / upload speeds) significantly.

Note that a 4G compatible mobile phone is backwards compatible with 3G, however a 3G-only device will not have access to the 4G network.

• What is VoLTE (Voice over LTE)

VoLTE or Voice over LTE is a feature that allows certain handsets to place phone calls over the 4G network, rather than falling back on 3G GSM networks. Without VoLTE, placing a phone call causes your phone to temporarily disconnect from the 4G network, pick up a 3G connection and receives / transmits voice data over 3G GSM.

Phone made on 4G networks are typically over SIP or session initiated protocol. This technology is quite similar to Skype or Viber.

VoLTE compatible devices

To see if your phone supports VoLTE, check your user manual or google online. In order to place a call on VoLTE, your mobile phone's hardware, firmware, software and the carrier that your phone is connected to must support the feature.

Some imported Android phones might not support VoLTE when used in Australia due to software or firmware limitations, and may require manual or 'unofficial' software / firmware updates in order to make them compatible with VoLTE.

This will be an essential feature once 3G networks in Australia are fully shut down in 2024. In the absence of 3G, any mobile phone that doesn't support Voice over LTE cannot place calls.

The below is a list of the various 4G / LTE Bands that your smartphone should ideally support:

• B1 2100 MHz FDD [Telstra, Optus Tasmania, Vodafone]
• B5 850 MHz FDD [Vodafone only, Rolled out in capital cities and regional Queensland]
• B3 1800 MHz FDD [Telstra, Optus, Vodafone]
• B7 2600 MHz FDD [Telstra, Optus]
• B8 900 MHz FDD [Telstra, a handful of sites, utilises spectrum previously used by 2G]
• B28 700 MHz FDD [Used by all major network providers, including Telstra, Optus, Vodafone, TPG]. This network frequency is particularly important for wide-area mobile coverage. To quote R-spectrum, this network band has “unmatched propagation characteristics permitting wide area coverage in regional and rural environments, and excellent in-building coverage”. B28 support may be especially important for users living in rural areas where cell towers are less common.

Note that it's often not enough to match up just a single frequency, as Australian mobile networks are built using multiple frequencies and not all frequencies are available at every location. For the best performance, and for 4G carrier aggregation to work, you should purchase a phone that supports all the LTE bands that the cell network provider uses.

What Information on specifications should I be looking for

The best way to ensure maximum compatibility with Australian carrier networks is to purchase your mobile device from a local retailer, and ensure that that device was designed for the Australian market. (This can also be important for consumer rights, such as warranty coverage, rights to repair or refunds).

Mobile phone manufacturers often produce different versions of a handset to suit the different needs & technologies of different carriers around the world. When importing a handset from overseas, check to see if the handset is compatible with the full range of LTE network bands that your carrier deploys. Keep an eye out for the model number of the device, as they're used to differentiate between devices built for different countries or regions of the world.

Googling a specific model number should give you an answer as to what country or region that device was originally intended for.

You also can visit GSM Arena or use Will my Phone work? to perform your research before you buy.

5th generation wireless systems refer to the ongoing deployment of improved networks that use low-band and mid-band sub 6 frequencies, as well as high frequency millimetre wave bands (mmWave) operating up to 60GHz. This can offer a theoretical peak data transfer rate of 20 gigabits per second although real-word performance tests conducted by Telstra in the Gold Coast has shown that their equipment can hit a peak speed of 3Gbps using mmWave bands.

The exact performance of 5G will largely depend on how the infrastructure is built, and which / how many of the different frequency bands you happen to be in range of when using the network.

You can read this article by Venturebeat to further understand how network providers use a combination of low band, mid band and high-band 5G radio spectrums to provide 5G network access.

As 5G allows more devices to connect to the network at the same time compared to 4G, it's expected that 5G can relieve network congestion as smartphone usage continues to grow.

It should be noted that 5G is not expected to fully replace 4G or 3G networks: instead, it will coexist with them and provide a faster fixed wireless internet alternative to 'traditional' fixed broadband or nbn. In addition, some MVNO's also do not offer 5G services as they aren't being sold 5G services by their supplying carrier.

To see if 5G is available in your area, simply consult your carrier's 5G Coverage & rollout maps. Note that 5G coverage is more limited compared to 4G, particularly in areas outside of capital cities and large metropolitan areas.

The following is a list of 5G bands currently in use.

* 3500MHz (n78) – Telstra (from May 2019)

* 3500MHz (n78) – Optus (from October 2019)

* 3500MHz (n78) – Vodafone (from March 2020)

* 2300MHZ (n40) – Optus (from June 2020)

* 700MHz (n28) – Vodafone (field tests May 2020)

* 850MHz (n5) – Telstra (from April 2020)

Cited sources and recommend reading:

• Whirlpool forums
• https://oztowers.com.au/Bands
• TelcoAntennas.com
• Whistle Out
• Wikpedia
• http://willmyphonework.net/