5G networks are ahead of us, and the next generation of wireless communication is powered by a new technology described as millimetre wave (mmWave).
US carriers are particularly interested in this technology and are likely to use it to varying degrees around the world.
However, not all 5G networks will necessarily use mmWave technology, at least not all the time.
As regards any new technology, there are inevitably problems and early obstacles that must be overcome before it becomes the main thing.
Millimetre-wave technology has had a fair share of sceptics in recent years, with questions being asked about its suitability over long distances, its ability to pass through walls and even whether rain or a user’s hand can block a signal.
These problems are not unfounded, but most have been resolved in recent years. mmWave technology will be on display to the public, so let’s take a look at the current state of those concerns.
First, let’s quickly summarize what a millimetre wave is.
A brief introduction to mmWave 5G
mmWave and 5G are used almost synonymous, but there are some critical differences between them. MmWave technology is only part of what 5G networks will use in the future.
You may have also heard of the “low band” and “below 6 GHz” frequencies, which will also be part of the standard and in combination will provide customers with, among other benefits, much faster data rates.
The term mmWave refers to a specific area of the radio frequency spectrum between 24 GHz and 100 GHz, which has a very short wavelength.
This part of the spectrum is hardly used, so mmWave technology wants to increase the amount of bandwidth available significantly.
Low frequencies are more congested by radio and television signals, as well as today’s 4G LTE networks, which are typically between 800 and 3000 MHz.
Another advantage of this short wavelength is that it can transmit data even faster, although its transmission distance is more concise.
Simply put, lower frequency bands cover much longer distances but offer slower data rates, while higher frequency bands cover much smaller areas but can carry much more data.
mmWave is only a part of the 5G picture, but operators especially like to talk about it because it allows too high bandwidth and displays the most impressive data transfer data.
MmWave aims to increase the data rate available in smaller and densely populated areas.
This will be a crucial part of 5G in many cities, with data entry in sports stadiums, shopping malls and convention centres, as well as in cases where data congestion can be an issue.
In rural towns and villages, the bands below 6 GHz and 2 GHz are likely to play a more vital role in ensuring consistent coverage.
Myth Hunter: Facts and Fiction of mmWave 5G
mmWave does not penetrate walls
This is perhaps the most common problem reported in upcoming 5G networks, and it is accurate to some extent.
Most building materials, like concrete and brick, attenuate and reflect very high-frequency signals with a loss large enough that you don’t get an instrumental signal travelling from the inside to the outside.
Even air creates a loss of signal, limiting frequencies above 28 GHz to about a kilometre anyway. Wood and glass reduce HF signals to a lesser extent, so you can probably still use mmWave 5G through the window.
This reflective feature works both ways – you don’t need a field of view with a 5G antenna to receive the signal. 5G networks will use air shaping to direct waves out and around obstacles on your phone.
This works in part because 5G instruments use multiple antennas to send and receive signals, combining data from various streams to amplify the overall signal and increase throughput.
It works both outdoors, reflecting the signs of buildings and indoors, mirroring the signs of the walls. Carriers could certainly install beamforming transmitters inside stadiums or large shopping malls.
In short, very high-frequency 5G signals do not travel very far and do not pass well outdoors. However, the massive MIMO and beam shaping ensures that a narrow line of sight is not a requirement for using millimetre waves.
The mmWave signal may not be able to penetrate buildings, but it will bounce around them to provide a decent signal. Indoors, people will have to rely more on LTE and signals below 6 GHz.
It can’t pass through your hands either.
This is also partially true for the similar reasons mentioned above. Human bodies block high-frequency radio quite well – part of us are in the water, and we are quite dense. That’s part of the reason Bluetooth headsets don’t always work if your body locks the phone.
While your hand is probably not enough to block the entire signal, it could undoubtedly interfere so much that a low or bad signal gets worse, or even unnecessary. It could at least slow down your speed or interrupt the flow of data.
In the worst case, holding the phone can make the difference between signal band one and zero. This is not good.
There is a solution to this complication: place antennas with a few millimetre waves around the phone. After all, it’s infrequent to cover both sides and the top of your phone at the same time.
Qualcomm’s benchmark design suggests that three antenna modules should be used in a smartphone to ensure robust signal coverage. Four if you upgrade to a 5G access point that can handle the extra power consumption.
Speaking of which, these three antenna modules do not need to be turned on at the same time. Smartphones turn these modules on and off, depending on which ones have the best coverage to reduce power consumption.
5G won’t work when it rains
It sounds perfect. It’s not that 5G doesn’t work in the rain, but there is some truth to this.
Like the two points above, the rain in the air adds an extra level of density and thus attenuates the signal as they move. Moisture can cause the same problem. However, this isn’t a new phenomenon for 5G.
“”The rain is fading” is a problem for modern GPS and other high-frequency satellite communication systems. Of course, they work all over space, and 5G will potentially have problems a few hundred yards away.
The millimetre wave signal strength will deteriorate slightly when it rains, leading to marginally slower speeds first and then potential connection issues.
The degree of decomposition will depend on the intensity of the rain and other factors, such as the distance from the cell phone tower. Rain will cause most of the problems when connected to the edge of the mmWave base station range.
mmWave harms your health
We’ve covered that here, and I won’t deign conspiracy theories any more – no, they won’t. Of course, I will always welcome further detailed research to help us better understand all the risks, but there are no credible indications of health risks.
mmWave does not go far enough for good coverage
mmWave is arguably the shortest-range technology used for next-generation networks, but it’s not too short to be unnecessary. Base stations will likely provide up to a mile of directional coverage, although 500 meters (~ 1,500 feet) is expected a safer bet given the obstacles and leaves.
This is not a large area. Many more base stations will require to be grouped to cover the same areas that now cover 4G networks. Therefore, we are unlikely to see mmWave roll out in the countryside or small towns. It’ll probably only be used in urban centres, where it covers the largest number of consumers in a small space.
Keep in mind that mmWave is only a small part of the broader 5G spectrum. The low band spectrum, below 6 GHz similar to Wi-Fi, should have you covered when high-frequency signals cannot reach you, providing a backbone that still delivers fast data speeds.
5G isn’t faster than gigabit LTE, so what’s the point?
We’ve already seen how our first LTE Gigabit networks are powered, delivering faster speeds than what we can use, so what good are the new, expensive 5G technologies?
Speed and, to an auxiliary extent, latency are two big selling points for consumers, and 5G makes it more accessible.
While 4G LTE can achieve gigabit speeds and above in ideal situations, in many countries, the spectrum or capacity cannot deliver these speeds to all consumers on today’s LTE networks.
5G is the most important for increasing the amount of bandwidth available by using a broader spectrum, which makes it easier to achieve gigabits and higher speeds.
Also, there will be many substantive changes with the possible release of the 5G standalone specification in the coming years. This will lead to notable changes in the types of cases that 5G, the massive internet of things, and smart cities, among others, can trigger.
5G and mmWave: the next big thing?
MmWave technology is the foundation for future 5G networks, enabling faster data rates and much higher bandwidth than ever before. The technology has limitations, mainly in terms of area and sensitivity to clogging, but it works.
Equipment vendors and carriers like Samsung and Qualcomm claim that it works very well. While carriers like to improve on their sleek new technology, mmWave isn’t the only area of spectrum helping build next-generation networks.
I’m still not undecided as to how big a difference 5G will make to the way we use our smartphones. I’m still waiting for this mandatory application.
5G’s promise of faster data rates could replace the need for wired fibre, reduce latency in AR and VR applications, and improve connections on the go, which sounds pretty good to me. mmWave is a vital part of building these next-generation apps.
