LLED Backhaul Project Engineer Blog

Celebrate MWC2022 Exhibit!

What is the Future of Mobile Phones and Optical Wireless Communications?

Last Update: February 27th, 2022

---

Introduction

I've been updating this blog on Tuesdays, but this time I'm going to update it today, Sunday.

This is because we will be exhibiting for the first time at the Mobile World Congress 2022, which starts tomorrow the 28th.

If you are in the telecom industry, you probably know about it, but for those of you who don't, let me give you a brief explanation of Mobile World Congress, commonly known as MWC. The MWC is the world's largest exhibition of mobile devices, mainly cell phones, and is held every February in Barcelona, Spain. 2019 saw the event attract over 100,000 people, but in 2020 and 2021, the MWC was cancelled (or postponed, to be more precise) due to the new coronavirus. In 2020 and 2021, MWC was cancelled (or postponed, to be precise) due to the new coronavirus. Along with CES (Las Vegas) for home appliances, MWC is one of the world's two largest exhibitions for digital devices. Before Corona, our company used to send several people to see the exhibits every year. I watched from the side as the people involved had a hard time dealing with the problems of "no air, no accommodation, and high prices," which is the usual problem with exhibitions of this scale, but it is an exhibition worth going to even if you have to go through such hardships.

However, it is an exhibition worth going to even with such hardships. Our company will be exhibiting at MWC this year. We're not just going to see it. We are exhibiting!　But, as you know, we're not going to have a booth by ourselves. However, as you know (?), we don't have the power or money to set up a booth on our own, so we'll be borrowing a booth from somewhere else and participating in a small way. But an exhibit is still an exhibit. This is a memorable first exhibition. The booth we will be borrowing from is the "Japan Pavilion**". The Ministry of Internal Affairs and Communications (MIC) will pay for a booth called Japan Pavillion, and we will create several small booths within the pavilion to introduce several Japanese companies. The booth fee is free of charge, but companies wishing to exhibit must go through a selection process by the Ministry of Internal Affairs and Communications. This time, we were lucky enough to be selected as one of the exhibitors. Lucky!

https://www.value-press.com/pressrelease/290631

https://www.mwcbarcelona.com/exhibitors/japan-pavilion

The exhibit is an LED backhaul** (LEDBH), which I have often introduced in this blog. A niche product called optical wireless communication is finally making its world debut.

MWC2022 will be held from February 28 to March 3, but it was uncertain whether MWC would be held under the situation of the spread of Omicron's stock, and furthermore, the opening of the Japan Pavillion, i.e. the participation of the Ministry of Internal Affairs and Communications in MWC, was officially decided about three weeks before the event. We were only able to prepare a simple exhibit. However, we hope that visitors to MWC will stop by the MTC corner in Japan Pavillion...

However, considering the real situation, especially the risk of infection and the quarantine period when returning home, I think that most people cannot even go abroad, let alone to Barcelona. I will introduce the booth structure and exhibits in another page or somewhere else, so this time I would like to write (in a rather roundabout way) about why MWC is exhibiting LEDBH and what the optical wireless team thinks about the relationship between cell phones and optical wireless communication in the future as a "preliminary feature". and what the optical wireless team thinks about the relationship between mobile phones and optical wireless communication.

Our optical wireless team's vision for the next generation of cell phone systems and optical wireless communications

Issues with 5G

We, San Gijutsu Kyoukai, are undertaking a lot of local 5G design and construction (or rather, optical wireless communication is our main business, not a sideline). To briefly explain Local 5G, it means that the "frequencies for cell phones" that used to be allocated only to cell phone companies (operators) will be allocated to anyone as long as they apply for it. What's more, the same level of frequencies as Docomo, au, etc. are being prepared for local 5G**. Until now, there was a similar system (BWA), but the frequency was too narrow to provide the same speed as existing cell phone companies, and the application conditions were too strict for anyone to apply. However, the new local 5G is open to "anyone" in principle. Of course, there are some restrictions on the location of the base station, but other than that, it is relatively flexible, so for example, if you build your own base station in your office, factory, or park, you can make your own cell phone. You may think, "I don't need to do that, I can use my cell phone. You may think, "I don't need to do that, I can use my cell phone." However, even within a limited area, the ability to have completely free communication has the power to change the world. No matter how many packets you use, no matter how many devices you add, you are free. What if we could increase the number of cell phone devices just like we increase the number of WiFi-enabled devices in our homes? Instead of connected cars, we may see connected bicycles, or even connected tricycles (Fig. 1). What would happen if public smart speakers were installed all over the city? (I don't know if this is a good thing or not.) Security cameras will be easy to install anywhere. We believe that true IoT is when there is enough bandwidth to connect anything, anywhere.

In order to create a world where everyone can realize true IoT, our company started to help build local 5G, but the reality was quite harsh.Even if the license application process is cumbersome to some extent, the equipment and lines are expensive. 5G is not only faster than 4G, but it is also much more complex and requires many more functions to be implemented, which naturally increases the price of the equipment. The line will also need at least 10G optical fiber if we use O-RAN^*1 like the existing operators. This means that to achieve local 5G, expensive radios must be connected with expensive lines. On top of that, the frequency is higher than before^*2, so the signal won't travel as far, and more radios will have to be prepared to cover the same area. This means that only people with money can use local 5G, and in fact, most of our local 5G customers are relatively large companies. In fact, most of our local 5G customers are relatively large companies. I feel that this is a bit far from our goal of "enabling everyone to realize true IoT. (Of course, it's great to get work from big companies, but that's a different story.)

Of course this (everything is expensive) should be the same for existing operators as well as local 5G customers. Of course, since the scale is different, radios and lines will be available cheaper than when building local 5G. But in return, there is a lot of volume (and half a dozen of them), so the cost of 5G deployment will be huge compared to what it has been in the past. The heavy burden has been proven by the fact that "5G coverage is not expanding as expected" in countries around the world even three years after the start of 5G. It will probably be a long time before 5G can be used nationwide in Japan as well as LTE, and the day when millimeter wave, which is called true 5G, can be used nationwide may never come.

Our vision of a next-generation system

The history of the evolution of cell phones can be described as the history of the improvement of frequency use efficiency, that is, the history of how much frequency is not wasted. The efficiency of frequency use has increased with each generation, and 5G has become a very complex system in order to raise the efficiency of frequency use to the limit. This has led to higher prices for equipment and lines, but technically, frequency use efficiency is almost as high as it can get... But is that really high frequency use efficiency?

Certainly, if the frequency is 800M or 2.1GHz, which can cover almost all of Japan with the existing number of base stations, the higher the frequency use efficiency, the better, even if the price of the equipment is a little higher. However, what is the point of increasing the frequency use efficiency of a system that has a small area per base station and therefore low population coverage (in the true sense of the word, not just a token number)? For example, a system with 90% technical frequency efficiency but only 20% coverage due to high prices of radios and lines, or a system with 60% technical frequency efficiency but low prices so that many radios can be installed and coverage can go up to 40%? Which is the "true" spectrum efficiency?

It is understandable that today's 5G millimeter wave radios have advanced features and a large number of antennas, which makes them expensive. However, if the result is "not used" or "does not contribute to the construction of the area at all", frequency utilization efficiency will be nothing. Therefore, we believe that the next generation cell phone system needs to be a system that can be installed more easily and anywhere, thereby enabling the installation of more base stations than ever before, and thereby increasing the "real" frequency utilization efficiency in millimeter wave and other frequencies that do not spread. I believe that this is what is needed for the next generation of mobile phone systems. The system should be simple in structure, inexpensive, easy to install (construction) and configure (integration), and require a minimum number of lines. Since it is a cell phone, shouldn't it be reliable? You may say, "Well, it's a mobile phone, so it should be reliable," but that can be achieved by using lower frequencies.

Our concept of optical wireless communication

On the other hand, when it comes to optical wireless communication, we are proud to be the leading manufacturer, so we can make various proposals. For example, if the radio wave to the user (mobile terminal) is millimeter wave, etc., and the backhaul line (backhaul line) is optical wireless, it is possible to realize the proposal.

In order to deploy base stations easily and quickly, it is necessary that they can be easily installed by anyone. It is also better if there is no need for troublesome license applications or coordination with other businesses. In urban areas where millimeter waves are required, it is not uncommon for utility poles to be underground, and it is quite difficult to install optical fiber, so wireless is preferable. And if you don't need to apply for a license, the less interference you cause to others by unlicensing, the better. If we list the necessary features, we can see that optical wireless communication is suitable for this. (This is a bit of a stretch, but...)

The image of the next generation (6G?) optical communication is as follows.

It may be hard to understand, but the millimeter wave radio is attached to the streetlight, and the next generation optical radio system is attached on top of it, carrying the backhaul. The optical radios will be cascaded, or "relayed" automatically, so that the millimeter wave radios can be installed as long as there is power. Instead of excessive beamforming to increase the maximum range of each radio, the millimeter wave radios will be loosely beamformed as in WiFi, but the radios will be cheaper, so more radios can be installed.

The current optical wireless communication devices (i.e., those exhibited at MWC) are still insufficient for 6G backhaul lines, so various advancements are needed. It will be necessary to increase the communication speed, and it will also be necessary to have a function to automatically adjust the direction. However, both of these are not that difficult to achieve with the current outlook. Communication speed is expected to increase with the evolution of devices, and automatic direction adjustment is a development of existing technology. We are also conducting research with the plan to put it to practical use before 6G.

So, at the MWC...

The MWC exhibit itself is a conventional product since it is in the LED back hall, but we will be exhibiting under the themes of "easy setup" and "easy to spread" to make it easier for 6G. It's not like this is going to change anything about 6G, but we want to let people know our stance, and we want to work together with others to achieve true IoT.

As mentioned above, the preparation period is short and the booth is a small, rented one, but this is our company's MWC debut. With the Corona disaster, the Ukraine problem, and other major headwinds for international exhibitions, we have no idea how many visitors will come to our booth, or what kind of visitors will come to our booth!

The results of the exhibition and the response will be introduced in my next blog.　Please look forward to it!

---