5G is (kind of) here. It certainly hasn’t changed my life yet. Or has it? Or will it? It appears that within the next couple of years 5G is expected to radically change the wireless landscape – and all of our lives – by enabling the Internet of Things (IoT), advanced AR and VR applications, and Smart Cities, just to name a few. Let’s discuss how 5G differs from 4G LTE and what it will do for us. But first, a quick word about 4G LTE.
4G and LTE
While 4G and LTE are often used interchangeably, they are not identical.
In March 2008, the International Telecommunications Union-Radio (ITU-R) released new standards for 4G (“Fourth Generation”) connectivity, including faster connection speeds and mobile hotspots. For mobile use, including smartphones and tablets, connection speeds need to have a peak of at least 100 megabits per second, and for more stationary uses such as mobile hot spots, at least 1 gigabit per second. These standards were groundbreaking at the time, and it took years for the nation’s cellular networks to catch up with the technology. Enter LTE.
LTE (Long Term Evolution) represents the industry’s attempt to bridge the gap between 3G performance and the difficult to achieve 4G specifications. It represents a significant improvement over 3G performance, while still not fully realizing 4G specs.
And since the ITU-R has no enforcement capability over what is marketed as “4G”, carriers simply started calling their current ‘best-effort’ technology as 4G LTE. Which is where we are today. 4G LTE, while not reaching the above performance goals, is a significant upgrade over previous 3G networks.
5G and 4G LTE
So, what’s so great about 5G? First, the bottom lines:
So how does 5G outperform 4G/LTE so significantly? By introducing and leveraging several new technologies to the game.
Currently, 4G/LTE wireless networks use radio frequencies of around 600 MHz – 2.5 GHz and this swath of spectrum is already pretty crowded. In order to realize the 10-20x speed improvement in moving around data, 5G will lean heavily on higher frequency bands, such as millimeter waves. This spectrum is from 30 to 300 GHz, resulting in wavelengths that are 10 to 1 mm. 5G is currently slotted to use 24 GHz – 52 GHz as well as 64 GHz – 82 GHz. These higher frequencies can inherently carry more information than lower frequencies but they are also subject to much more interference and absorption and therefore have significantly shorter ranges. As a result there will also be significant 5G spectrum at sub-6 GHz (450 MHz – 6 GHz) which will help recover some of that lost coverage area at the expense of speed. And of course 5G will also have access to all existing wireless spectrum.
In fact, 5G networks will likely utilize 3 separate sub-bands: A low-frequency band for more coverage area (sub 1GHz), a mid-frequency band for a better blend of coverage range and speed (1-6 GHz), and the high-frequency band for maximum bandwidth and throughput (above 6 GHz). 5G networks will also significantly leverage 4G spectrum and infrastructure as the technology develops.
A more detailed discussion of 5G spectrum can be found here.
Currently, cellular coverage is obtained by using relatively large, high power cell towers that are relatively far apart. This is due to the fact the lower frequencies in use today (600 MHz – 2.5 GHz) are able to travel great distances without being significantly absorbed or scattered by the environment. These longer wavelengths are pretty good at passing through, or going around, many obstacles. Not so with millimeter waves. As a result, the range is dramatically reduced. To counter this reduced range, 5G networks will use many smaller, lower power cell towers/sites that will be placed much closer together. With the reduced wavelength also comes reduced antenna size, so it will be feasible to have small backpack-sized cells located more discreetly – they could be located on lamp posts, building eaves, traffic lights, etc. The idea is that you always need a direct “line-of-sight” to one of the mmWave cells to ensure a rock-solid connection.
5G will also rely heavily on 5G Macro Cells. As mentioned above the 5G mmWave antennas are much smaller than current cell tower antennas so you can pack a bunch of these smaller antennas together into a relatively small physical space – up to 100 separate antenna elements per base station. Also, each antenna element will utilize MIMO (multiple input, multiple output) technology, which allows them to send and receive more data simultaneously.
Another unique aspect of 5G will be beamforming. The 5G macro cells will have an operational mode somewhat like a phased-array radar – multiple antenna elements can be combined together using advanced signal processing techniques to “steer” the radio signal in a desired direction. This essentially allows you to operate the macro cell as a collection of many high-gain antennas, with improved SNR (signal-to-noise ratio) for the end user.
5G will also use full-duplex communications, compared to the half-duplex mode utilized by today’s networks. Generally speaking, an antenna cannot simultaneously transmit and receive information, due to interference between the 2 signals. As a result, current 4G/LTE networks typically use 2 antennas – one for transmitting and another one (at a different frequency) for receiving. By going to full duplex, 5G networks will double the capacity of current wireless networks and can utilize the same physical antenna for both transmit and receive.
A fundamental problem that 5G full duplex addresses is the phenomenon of ‘reciprocity’ – which refers to a radio wave’s tendency to travel in both directions along the antenna. Any radio wave interacting with an antenna will naturally reflect off any electrical discontinuities in the antenna, causing interference with other desired signals. To address this, 5G networks will utilize some ultra-high speed switches within the antenna which can work to both cancel this unwanted interference as well as delay transmit or receive signals in order to minimize interference.
5G – Present and Future
Well, of course with 5G you will be able to download movies and updates to Candy Crush and Minecraft virtually instantaneously. And while faster, more responsive smart phones are great, that is only a very small part of the 5G pie. All major carriers are already heavily invested in building out 5G networks and most of them have some sort of a presence already. It figures to be another couple of years before we see widespread 5G adoption. PC Magazine has a great summary article and also a nice, concise “Race to 5G” site where you can see which carriers are currently leading the way.
Also very interesting is the 5G rollout strategy for each carrier. Verizon seems committed to jumping immediately into millimeter wave technology and accepting the very limited ranges in small, city block-by-block buildout, while T-Mobile has already rolled out a nation-wide 5G network that leverages low-band (sub 1GHz) and mid-band frequencies so their coverage area is much broader although not as fast as peak 5G speeds will be. An excellent video that discusses this in more detail using a McLaren OnePlus 7T Pro 5G phone can be found here. As an added bonus, you get a quick walk-through of the 2020 McLaren GT supercar, priced at only $210,000. Perhaps you can purchase the car and have the phone thrown in for free?
The combination of the three big benefits of 5G – more and faster data (higher bandwidth), more responsive communications (lower latency), and the ability to handle many more devices per area will result in a world that is much more integrally connected via wireless communications. This will enable some truly transformative uses and technologies:
5G is starting to fundamentally change the wireless communications landscape and it’s just getting started. Certainly we should see many of the changes listed above. Also certain is that there will be many more use cases and applications we haven’t even dreamt of yet.
Rob Stone, Mushroom Networks, Inc.
Mushroom Networks is the provider of Broadband Bonding appliances that put your networks on auto-pilot. Application flows are intelligently routed around network problems such as latency, jitter and packet loss. Network problems are solved even before you can notice.
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