Gigabit LTE: Paving the road for the 5G revolution
Gigabit LTE is a mobile connectivity milestone, delivering upstream and downstream speeds far in excess of what most wired broadband connections currently deliver. It’s a technology with transformative potential for everything from cloud-based software and services to mobile virtual reality, augmented reality, video streaming, automotive computing and more. Yet the promise of Gigabit LTE goes further. As companies like Qualcomm® and its partners in the 3GPP alliance invest in Gigabit LTE they’re laying the foundations for the next generation of mobile connectivity, 5G NR. If Gigabit LTE is a major step change, 5G NR is positively revolutionary; not so much a set of mobile network standards as the underlying connectivity layer for the world of the future.
The journey so far
To understand why Gigabit LTE is so important for 5G, you need to understand how mobile connectivity has developed so far. Take 3G as the starting point of mainstream mobile internet, with the standards defined by the 3rd Generation Partnership Project (3GPP) – a group of telecoms associations from around the world – enabling a graphically-rich mobile experience for the first time. 3G harnessed newly-available radio frequencies (900MHz and 2100MHz in the UK) and High-Speed Packaged Access (HSPA) technology to deliver maximum peak download speeds of up to 14.4Mbits/sec. The arrival of HSPA+ in 2010 pushed that up to 63Mbits/sec.
HSPA+ was fast, but new applications like HD video streaming or cloud computing needed even higher network capacity to achieve faster throughput. In response, the 3GPP defined new standards based as an evolution of UMTS technology, called Long Term Evolution (LTE). The fundamental technology behind today’s 4G networks, LTE used new signal processing techniques and modulations to enable more bandwidth over new frequency bands – 800MHz, 1800MHz and 2600MHz in the UK – taking peak download speeds up to 150Mbits/sec and real-world download speeds to up to 30-50Mbits/sec.
In the last few years, LTE has been enhanced to bring in a new standard, LTE Advanced, taking LTE and adding Carrier Aggregation and MIMO capabilities to boost speeds further. Carrier Aggregation means combining several signals, potentially on different frequencies, to use more bandwidth. If you think of your mobile data connection as a road carrying heavy goods vehicles, it’s like turning a normal single carriageway into a dual carriageway or multi-lane motorway.
And MIMO? Multiple Input Multiple Output is a technique of using multiple antennas on both the device and the transmitter to create more radio links, so that data can flow through two or more data streams at once. In effect, it’s like taking our motorway and stacking another one on top, so that even more traffic can keep moving through at maximum speed. LTE Advanced is a backwards compatible upgrade to LTE, so existing users aren’t affected – in fact they benefit from the additional capacity created in the network due to these upgrades.
The Next Step
LTE Advanced was never the end of the LTE road, but there are two ways you can look at its successor, LTE Advanced Pro, or in its most commonly known form, Gigabit LTE. On the one hand, Gigabit LTE is an upgrade to LTE Advanced, taking speeds even further. On the other, it’s a roadmap for the future, laying down the foundations of the 5G networks of 2020 and beyond.
Why? Firstly, Gigabit LTE defines a whole new category of speed. With maximum peak download speeds in excess of 1Gbits/sec and real-world speeds of up to 750Mbits/sec, Gigabit LTE empowers mobile devices to tackle the most demanding applications – even those that would once have been the sole preserve of PCs, games consoles and media streamers operating over a wired internet connection. In fact, Gigabit LTE could potentially obviate the need for a home broadband connection altogether.
This comes down to a killer combination of Licensed Assisted Access, four-way MIMO and 256-QAM. The first, LAA, is a new form of carrier aggregation, combining bandwidth in the open, unlicensed 5GHz network with bandwidth in the licensed 4G spectrum to open up a four-lane super motorway where traffic is free to move at even greater speeds. It then uses MIMO to stack that motorway four levels deep.
256-QAM, meanwhile, is a form of modulation that packs more data into each vehicle on the motorway, making maximum use of all that bandwidth. Combine this with further enhancements that reduce latency on the connection, cutting down any lag that might make an application feel less responsive, and you have a mobile network that’s ideal for streaming VR content, handling data-rich business applications or even working with AI applications – including driverless cars – at a distance.
5G on the horizon
In fact, Gigabit LTE is such a step change that you might wonder why it’s not the basis of the next-generation 5G networks. Well, in many respects 5G NR is an evolution of Gigabit LTE. The proposed standards use an enhanced form of LAA to give you faster sustained upload and download speeds. MIMO, meanwhile, becomes Massive MIMO, whereby dozens of antennas on the mast work in concert to track your device and focus radio energy squarely at it, givng you vastly faster speeds. Radio latency will be reduced to below 1ms, giving you web based apps, games and VR experiences that feel like they’re running on the device and making the wait while data loads unnoticeable.
However, the crucial element of 5G NR is the NR, or New Radio. This means changing the radio waveforms, the transmission frameworks and the channel coding schemes that control how data moves across the network, while making use of bandwidth in the underused millimetre wave (mmWave) spectrum – in the 24 to 60GHz range – to accommodate even more data moving at even greater speeds. With 5G NR, we could be talking download speeds of anywhere between 2Gbits/sec and 8Gbits/sec on networks designed to handle much higher peak demand.
Gigabit LTE is crucial
But if 5G NR could supersede Gigabit LTE in the early 2020s, will the latter still matter in a few years’ time? Surprisingly, yes. Even once 5G NR starts rolling out, Gigabit LTE will still be needed as a high-speed coverage layer, providing a consistent experience in areas where 5G NR isn’t yet available and ensuring that the devices and applications that rely on high-speed connectivity still work outside 5G range. Effectively, Gigabit LTE will do for 5G NR what 3G and HSPA+ did for LTE or EDGE did for 3G.
Secondly, Gigabit LTE delivers a platform on which manufacturers, developers and service providers can build and introduce the products that go mainstream with 5G. Gigabit LTE is fast enough and stable enough to cover rich mobile VR and AR applications, AI devices, driverless cars and Ultra HD entertainment services. It has the reach and throughput to support the burgeoning Internet of Things. That means that, when 5G launches, there will be mainstream applications primed and pumped to take advantage of the extra bandwidth, on networks that have scope to grow with the massive-scale proliferation of services and devices. As the world changes and the need for high-speed connectivity becomes ubiquitous, the network infrastructure will be there to support it.
In short, Gigabit LTE both sets the stage for 5G and will play a crucial role even after 5G’s arrival. The Gigabit LTE devices of today, based on the Qualcomm® Snapdragon™ 835 Mobile Platform with Gigabit LTE, will give users the best mobile experiences today and a way in to the even-better experiences of 2020 and beyond. That’s why Gigabit LTE matters now, and why it’s so important for the future.