What is 4G: Technology
The main reason 4G is faster than 3G is because of Orthogonal Frequency-Division Multiplexing (OFDM). It sounds complicated, but it’s the same technology used in Wi-Fi, ADSL broadband, digital TV and radio.
OFDM is a technique for squeezing more data onto the same amount of radio frequency. It also reduces latency and interference. Data is split up and sent via small chunks of frequency in parallel, therefore increasing the capacity of the network.
Multiple-input and multiple-output, or MIMO, is another reason 4G is able to provide faster speeds. It is simply the use of multiple antenna arrays at both the transmitter and receiver to improve communication performance.
4G
4G is the fourth generation of wireless mobile telecommunications technology, succeeding 3G. A 4G system must provide capabilities defined by ITU (International Telecommunication Union) in IMT Advanced (International Mobile Telecommunications-Advanced). Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television.
What is 4G LTE
An acronym for Long Term Evolution, LTE is a 4G wireless communications standard developed by the 3rd Generation Partnership Project (3GPP) that’s designed to provide up to 10x the speeds of 3G networks for mobile devices such as smartphones,tablets, netbooks, notebooks and wireless hotspots. 4Gtechnologies are designed to provide IP-based voice, data and multimedia streaming at speeds of at least 100 Mbit per second and up to as fast as 1 GBit per second.
4G LTE is one of several competing 4G standards along with Ultra Mobile Broadband (UMB) and WiMax (IEEE 802.16). The leading cellular providers have started to deploy 4G technologies, with Verizon and AT&T launching 4G LTE networks and Sprint utilizing its new 4G WiMax network.
What is VoLTE?
VoLTE stands for voice over LTE and it’s more or less exactly what it says on the tin. It’s voice calls over a 4G LTE network, rather than the 2G or 3G connections which are usually used. We tend to think of4G as mostly being about downloading, streaming and web browsing, and indeed that’s primarily what it’s been used for so far, but it can also be used to improve calls.
What are the benefits of VoLTE?
Superior call quality – The big advantage of VoLTE is that call quality is superior to 3G or 2G connections as far more data can be transferred over 4G than 2G or 3G. Up to three times as much data as 3G and up to six times as much as 2G to be precise, making it easier to make out not only what the person on the other end of the line is saying, but also their tone of voice. Essentially it’s an HD voice call and it’s a much richer experience over all.
Improved coverage and connectivity – VoLTE can connect calls up to twice as fast as the current methods and as 2G and 3G connections will still be available when there’s no 4G signal it simply means that there’s greater mobile coverage overall, as currently places with a 4G signal but no 2G or 3G means that one you can’t make or receive calls.
You might think that would be a rare occurrence, but some of the frequencies that 4G operates on, such as the 800MHz spectrum, have far greater reach than 2G or 3G spectrum, so you’ll be able to get signal further away from a mast or in buildings which other signals struggle to penetrate. Indeed, Three is fully relying on its 800MHz spectrum for VoLTE calls.
However, while 2G and 3G services would likely remain they wouldn’t be as necessary as they are now and much of the spectrum used for 2G in particular could potentially be repurposed to increase capacity on 4G networks.
Better battery life – Anyone who currently uses 4G could also find their battery life increased with VoLTE, as right now whenever you make or receive a call your phone has to switch from 4G to 2G or 3G, since 4G calls aren’t supported (other than on Three Super-Voice) and then once the call is finished it switches back again. All that switching, plus the need to search for a different signal each time, can give the battery a significant hit.
Video calling – It’s also theoretically possible to make video calls over 4G, much like a Skype call except you’d just use your mobile number and be able to use the regular dialler and call interface, so you can make and receive video calls from anyone else with VoLTE, rather than relying on separate accounts.
In fact you may have noticed that Skype and other existing video calls services often seem to have superior audio quality to voice calls. That’s because like VoLTE they use more data as part of a similarly named VoIP system, so you can expect your voice calls to start sounding more like Skype calls, but they won’t hit your battery life as much as Skype does.
Not only could video calls become native to the dialler, but other Rich Communication Services (or RCS’s) could as well, such as file transferring, real time language translation and video voicemail and there may be applications which haven’t even been thought up yet.
As VoLTE is tied to data it could also mean that you won’t have to worry about how many minutes you use, as everything will fall under data use.
Are there any limitations of VoLTE?
Initially there are a few. For one thing in some implementations it only works if both the device making a call and the one receiving it support VoLTE, so in the early days you might find yourself quite limited in terms of who you can actually use it to contact.
Depending on how the networks set it up there also may or may not be network interoperability at first, so it’s possible that initially you may only be able to use VoLTE to call people on the same network as you.
VoLTE also potentially requires both participants on the call to have 4G coverage. As that’s not yet as widespread as 2G and 3G it means that VoLTE calls won’t always be available and if someone moves out of 4G coverage during the call there’s a chance that the call will be dropped.
Finally, pricing may be an issue. Since VoLTE ties into data it may be the case that calling becomes more expensive than it currently is, depending on what networks decide to charge.
All of these problems are likely to be short-lived though as 4G coverage increases, more devices begin to support VoLTE, prices stabilise and networks align their technology. In fact Three’s version of the service (which is the only live one in the UK) suffers from very few of these problems, with the only major ones being lack of VoLTE coverage and limited support for existing handsets.
Why haven’t we been making calls over 4G with VoLTE all along?
The problem with Voice over LTE is that 4G LTE is a data-only networking technology, so it doesn’t natively support voice calls. While 3G and 2G were primarily designed with voice calls in mind and data was added to them.
As such it’s been necessary to create new protocols to support voice calling over 4G and it’s a big job, requiring upgrades across the entire voice call infrastructure. There’s no one standard for this, with different networks creating their own solutions.
There are some common problems and solutions though, most notably the requirement for Single Radio Voice Call Continuity (SRVCC), which simply means that the phone will be able to switch back to a 2G or 3G signal if you move out of a 4G signal zone during the call.
This needs to be seamless or the call will cut out, so it requires masts to pre-emptively deliver a 3G signal whenever the 4G signal drops dangerously low, but also to keep the 4G signal running at the same time, so it can either stay on 3G if it loses the 4G signal entirely or drop the 3G if the 4G signal becomes strengthened again.
How do I know if my phone supports VoLTE?
If you’re using a 3G handset then you’ll definitely need to upgrade, but if you have a newer 4G enabled one then it might work with VoLTE (though it will require a software update first).
What is the difference between TDD-LTE and FDD-LTE?
The cellular networks, a limited shared resource (spectrum) needs to be shared with all users so full duplex communication is possible. The two main methods used are:
1. Time Division Duplexing (TDD) – The communication is done
using one frequency, but the time for transmitting and receiving is
different. This method emulates full duplex communication using a
half duplex link. And switches between up and down in turn as a ‘ping-pong’.
2. Frequency Division Duplexing (FDD) – The communication is
done using two frequencies and the transmitting and receiving of
data is simultaneous. It is symmetric and uses two frequencies one up, one down.
FDD LTE (FD-LTE) vs TDD LTE (TD-LTE) Networks: FDD LTE and TDD LTE are two different standards of LTE 4G Technology. LTE is a high speed wireless technology from 3GPP standard. 3G growth ends up at HSPA+ and mobile operators have already started deploying 4G networks to provide much more bandwidth for mobile users. 4G speed will give us a virtual LAN reality to mobile handset by offering very high speed access to Internet to experience the real triple play services such as data, voice and video from a mobile network. LTE is defined to support both paired spectrum for Frequency Division Duplex (FDD) and unpaired spectrum for Time Division Duplex (TDD). LTE FDD uses paired spectrum that comes from a migration path of 3G network whereas TDD LTE uses unpaired spectrum that evolved from TD-SCDMA.
