This is a short primer that covers how mobile phone signals work, how each generation (e.g 2G, 3G, and 4G) differs from the last and what type of phone you should consider buying if you want to ensure you have the best possible coverage, call quality and internet speeds from your device.
Before we begin please take note that I am not an expert in this subject and can only offer a fairly basic explanation. Questions relating to whether what works / what doesn’t is fine, but more technical queries should be directed towards your carrier / provider.
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.
What this means for you : Users of older mobiles that ONLY use GSM signals will no longer be able to access mobile services once 2G is shut down in Australia. Likewise, users of DUAL SIM handsets that typically have 2G-only services in their second SIM slot will no longer be able to make / receive calls on their second SIM.
If you still own a 2G phone, you can probably give it away, ebay it or donate it to the needy.
Don’t worry about whether your new phone supports 2G or not, because it’s obsolete technology anyway.
- 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 Android phone. In this mode, you might not be able to access data services, but can still make or receive phone calls via the GSM network. EDGE is not considered a true 3G standard however.
In Australia, three 3G frequencies are:
- 850MHz (B5) – Telstra, Vodafone
- 900MHz (B8) – Optus, Vodafone
- 2100MHz (B1) – Telstra, Optus, Vodafone
- What this means for you: Many smartphones nowadays should cover at least all three of these 3G frequencies. However, beware that some budget phones imported from say, China, may only cover 850mhz or 900mhz, but not both, in an effort to cut down on production and licensing costs. Avoid getting a phone that does not support all three frequencies.
- 4G LTE is probably of the greatest interest and is probably the most confusing to most. LTE is the next-step of the evolution of UMTS (3G) and HSDPA (3.5G) is a complete redesign and simplication of 3G network architecture resulting in a marked reduction in transfer latency. Because of this, LTE is not compatible with 2G and 3G networks and thus, functions on an entirely different wireless spectrum. Unfortunately, this means that erecting an LTE network requires it to be built from the ground up. This is one of the main factors behind the delayed launch of complete 4G LTE networks.
The industry is using what is called LTE Categories to describe the LTE network capabilities. There are 11 different categories that are defined, and from a consumer perspective, they mainly differ in terms of theoretical speed. The whole table can be seen here.
According to Wikipedia, CAT6 LTE provides a max downlink speed of 301.5 Mbit/s, which is pretty damn fast. Cat 6 is already available in some metro areas for users with Telstra and Optus, and in testing we’ve seen real-world download speeds of 150Mbps and uploads still around the 35-50Mbps mark.
- What is VoLTE
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.
VolTE changes this, by allowing phone calls to be placed on 4G networks, 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. Not every device supports VolTE and most carriers require your phone to be running their own firmware or operating system in order to have access to VolTE features. As such, many imported phones might not support VolTE when used in Australia.
Australia is currently using these LTE bands
- 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 Telstra and Optus, but not Vodafone]
- B40 2300 MHz TDD [Optus (Vivid Wireless)]
The above is a list of 4G LTE frequencies. Some of these frequencies may overlap across different telcos, some do not, but you can generally expect that Telstra will provide the best experience in terms of signal strength and coverage.
What Information on specifications should I be looking for
It’s pretty easy to work out what you should buy. Different phone manufacturers may produce specific models for different regions and countries, so often the best way to ensure you get maximum compatibility is to just buy the Australian model from a local store. For example, the Nexus 5X comes in a few different versions.
However, if you’re importing from overseas you might run into some issues where the phone might only partially support your carrier and you might be missing some crucial (or not so crucial) LTE bands. Use GSM Arena or use Will my Phone work? to find out what frequencies are supported and do your research before you buy!
Some comments regarding these frequencies
*1800 is the current anchor. If you’re buying a new phone, make sure 1800 is supported.
*700 will have the widest and deepest coverage. Why? Low frequency signals penetrate better. If you’re buying a new phone and you are using Telstra / Optus, this is beneficial to have. Do you REALLY need it though? That depends. Internet surfers may find it more difficult to achieve full 4G speeds while inside a building or underground, but those who don’t utilize mobile data as much could live without it.
*2600 might not have wide coverage (primarily where you would have congestion without it) but it has the highest capacity. Basically, in metro areas, this will be pretty important.
*900 and 2100 is very uncertain, but likely rolling out to supplement other frequencies.
Regarding the B28 700mhz 4G LTE frequency: Telstra is now offering CAT6 services on this spectrum. This is called Telstra 4GX and for CAT6 services to work your device must support B28.
Just like Telstra, Optus too have begun the rollout of their 700 and 2600MHz LTE networks, so make sure your new Optus device also supports the bands listed above, along side 1800mhz and 2100mhz
There’s not a lot of publicity about the new 2600MHz 4G network, but despite having a very short range it’s important to help reduce congestion in densely populated areas such as city centres where the operation of a long range transmitter would have considerable self interference (due to the long reuse distance required).
Cited sources and recommend reading:
- Whirlpool forums
- Whistle Out