The Radio Waves for Comiket 108 Are Rebuilt from Scratch Every Time

This year's Summer Comiket is on August 15th and 16th. I imagine many people have already started preparing.

This event will be different from previous years in several ways. Due to large-scale renovations at Tokyo Big Sight, East Halls 4-6 will be unavailable for a year. Consequently, circles will be spread across East Halls 1-3 and 7, West Halls 1-2, and South Halls 1-2, while corporate booths will be located in West Halls 3-4 and South Halls 3-4. The number of registered circles is over 30,000, the highest since the pandemic began. The opening time has also been pushed back from 10:00 to 10:30.

Since this information has been provided by the official sources and various other places, I think many people are already aware of it.

What caught my attention was what lies beyond that.

If the layout of the venue changes, the location of the waiting lines also changes. And when the location of the waiting lines changes, the radio waves for those two days must be rebuilt entirely from scratch.

As I looked into it, I found that more effort was being put into this than I had imagined.

It takes two months for a single base station.

This is a photo I took when I visited Big Sight on a weekday a while ago. It is completely unremarkable. It is just an ordinary scene with people walking by.

And then, on top of this scene, for those two days only, several layers are built up.

Normally, base stations do not move. They are located on building rooftops or steel towers, facing the same direction in the same spot for years.

But the two days of Comiket are different. A significant portion of the radio waves at that place on those days is made up of temporary arrangements.

During Comiket 107 at the end of 2025, Docomo deployed three mobile base station vehicles to the East waiting area. One of them was what the company calls its first “three-sector MMU vehicle,” which can cover a wider area than before by pointing directional antennas in three directions. For the West waiting area, they set up one temporary base station aimed at the line in the Center Promenade.

The story of this one station left the biggest impression on me.

It is said that the person in charge spent about two months negotiating before they finally received permission to install it.

Two months for one station.

Moreover, no one will likely ever praise them for whether it was useful on the day of the event. People waiting in line will just look at their smartphones, watch videos without any issues, and that will be the end of it.

This was not just the case for Docomo. SoftBank also wrote in their own article that their radio wave countermeasures for Comiket “begin more than two months in advance.” Two months seems to be the standard duration for this work, not just a circumstance for one specific company.

What surprised me even more was that it wasn't just about increasing the radio waves. They also adjust the regular base stations around the venue so that they don't pick up signals in the target area. They call in reinforcements and tell the local standing army to stay quiet. This is because radio waves don't necessarily get better the more you add; if they overlap poorly, they interfere with each other.

The base station at Kokusai-Tenjijo Station on the Rinkai Line also has its orientation adjusted so that radio waves are concentrated in the direction where the crowds are. The antennas at that station point in a different direction for those two days only.

It seems obvious once you're told, but I had always just thought, 'It must be hard to connect because there are so many people.'

In reality, it was the opposite. The connection is actually much more carefully engineered.

They redo everything the year after they get scolded.

I found another good story.

At the Summer Comiket in 2023, the 5G infrastructure was not ready in time. The venue was large, there were many people, and there were not enough radio waves. Docomo itself reflects that they received many harsh comments from attendees.

The following year, they completed construction on all base stations at the venue and achieved full 5G coverage.

It took one year.

Since this is a matter of large-scale equipment, it must have required budget, construction time, and negotiations. They accomplished all of that in one year in response to just one summer of dissatisfaction. Moreover, they didn't just end it with 'We apologize for the inconvenience,' but properly returned results the following year.

Reading the details, it becomes a bit more specific. The time available for equipment upgrades for temporary base stations is only about four months between the Summer and Winter Comikets. It is said that extraordinary speed was required, and work continued until just before the event. In the East waiting line, they even adopted a method of connecting mobile base station vehicles to small base stations several dozen meters away with cables, lining up temporary base stations at equal intervals.

I have done this kind of work before, so I know that this is quite difficult. Even if it is effective, it won't be in the newspapers. It only gets reported when it fails.

And on the day of the event, it doesn't end with just placing the equipment. During Comiket, Docomo monitors social media and analyzes posts about the communication environment. When many comments about a specific location are gathered, the local staff actually go there to inspect the equipment.

Someone somewhere at the venue writes, 'I can't connect here.' There is someone reading that, and they are running to that spot. They do that for the entire two days.

That is why years when the line location changes are difficult.

This time, the waiting area for general participants is the East Parking Lot for the East District, and Symbol Promenade Park for the Southwest District. Admission tickets are also divided between East and Southwest.

While reading the preparatory committee's newsletter, it was written that regarding this Southwest side, part of the park was being used for an event related to the opening of Tokyo Dream Park, and it was still under adjustment as of June. Regarding the East side, it says that because it is no longer possible to move directly between East Halls 6 and 7, the admission operation from the East Parking Lot is quite different from before.

In other words, who will line up where and for how many hours is not completely finalized until the very last minute.

From the perspective of a world where it takes two months to set up a single base station, I think these are quite tough conditions. If the line moves by 100 meters, the parking location for the vehicles and the angle of the antennas also change. It is no longer a matter of just parking them in the same place as last year.

This year is probably a more difficult year than usual.

Looking at it that way, if it connects normally on the day, I think that is quite an achievement.

What they are carrying is not a base station

I think some of you may have passed by someone carrying equipment at the venue. I have seen it several times myself. At first, I thought it was for delivery or something.

That is not a base station.

It is what KDDI calls "Human Wi-Fi," where staff equipped with small Wi-Fi access points walk around the venue. It seems one person can accommodate about 100 devices. Depending on the event, they might even be in cosplay. Docomo has the same idea, making d Wi-Fi available at the venue.

The reason they don't carry base stations is because they can't.

The frequencies used by base stations require a radio station license. It is a band allocated by the government, so it cannot be increased arbitrarily, and interference with the surroundings must be adjusted. That is why it takes two months of negotiation. On the other hand, the 2.4GHz and 5GHz bands used by Wi-Fi do not require a license. Anyone can use them that same day.

Places where cars cannot enter, small blind spots in buildings, around the front of the line. People walk around to fill the gaps that cannot be covered by fixed equipment.

In other words, that person is walking around looking for "where the people in the most trouble are." Humans go on their own two feet to places that cannot be covered by equipment. I thought it was kind of nice that even though we were talking about technology, it ended with people carrying it around.

And apparently, they sometimes even do cosplay. Even though it is serious work, they are coming to entertain.

There is also an example that swung in the opposite direction. At last year's Summer Comiket, SoftBank used Starlink Business to set up a Wi-Fi environment. It is a satellite. For places where it is difficult to lay terrestrial lines, they bring it from the sky.

While people are carrying it around, they are also pulling it from satellites. For the sake of the same two days, they are reaching out to both extremes.

Things to do on the day

Since we are at it, I will write down how to make it easier to receive from this side. It would be a waste to miss out on what they have prepared for us just because of one setting on our end.

1. Keep 5G settings turned on

Those who support it should also use the SA option. 5G SA completes communication solely within 5G, so it is less susceptible to the congestion of 4G. When the media measured it at the same location during Comiket 107, 5G NSA was 125.0 Mbps download, while 5G SA was 249.2 Mbps. Docomo is also officially calling for people to "please turn it on at least during the event period."

You can use the faster path that has been prepared with just one setting.

2. Set up carrier Wi-Fi at home

If you try to set it up on-site, the setup process itself requires communication. It is easy to end up in a sequence where you want to set it up because it won't connect, but you can't set it up because it won't connect.

The name differs depending on which line you use. For Docomo, it's d Wi-Fi; for au, it's au Wi-Fi; and for SoftBank, it's SoftBank Wi-Fi Spot, each corresponding to their respective public wireless LANs. In many cases, you won't be able to connect automatically until you install the dedicated app and the configuration file known as a connection profile. Depending on your contract plan, you may need to sign up in advance.

The procedure varies by company, so please check the official guides for the fine details. However, the SoftBank explanation page states: Please perform the settings while connected to the mobile network.

In other words, do it at home.

The radio waves carried by people walking around only reach those who have prepared to receive them.

3. Bring cash

As someone who works in payments, this is what I want to say most. Cashless payments at circles are currently dominated by Square and AirPay, but those systems essentially work on the premise that your smartphone is connected to the internet. Conversely, if it doesn't connect, you can't sell or buy. Even a momentary stall means that table will only be able to accept cash for a while.

The same goes for sellers; circles that support cashless payments should definitely have cash change ready. It would be a shame if something you worked hard to create couldn't be bought due to radio wave issues.

4. Battery and heat

In areas with weak signals, your device will keep searching for a signal, which generates heat and drains the battery. This year, it's so hot that East Hall 8 will be opened as a temporary rest area for people waiting in the East Parking lot queue as a heatstroke countermeasure, so if the device itself gets hot, its performance will slow down just from that.

By the way, this temporary rest area is being handled the same way as last summer. In a year where three halls are unavailable and managing space is difficult, they are still properly providing a place to rest.

Finally

If you connect normally on the day, you probably won't notice anything at all. Even if three mobile base station vehicles are parked there, they won't enter your field of vision. You'll stand in line, check your social media, enter the venue, and that's it.

But that is not a failure; it is a success. This job is designed to become invisible the better it works.

This year, I think I'll try to look for them a little bit. Where the people carrying them on their backs are walking, which way the vehicles are facing, and where the one unit that took two months to get permits for is standing. I won't talk to them even if I find them, but I feel like it's enough just to be one person who notices.

Besides, if I write something here, someone will probably read it.

If you were able to connect, it means someone was preparing for it starting two months ago.

On those radio waves, many books will be sold again this year, and many people will meet their favorites.

It's hot, so let's bring water.

Every day, I break down the "discrepancies" between everyday items and money. Follow me to receive the next update.