Question Please recommend a Router + AP solution for 500+ drones ?

[gafonator]

Hi, guys,

We've recently pulled off a pretty decent drone show with tens of drones — everything went smoothly using just one (expensive) MI-MO router. Now, we'd like to scale up. We're aiming for hundreds of drones — 500+, actually. But choosing the right WiFi solution for that is slowly becoming a bit of a nightmare. Everyone says something different.

The nutshell version:
We're talking about 500+ clients on a WiFi network, with a large number of concurrent UDP multicast streams running — and we need it all to run as close to perfectly as possible. The distance from the router/AP antennas can reach up to 250–300 meters.

If you’re familiar with such setups, or if you can offer some insight based on your broader networking experience (e.g. which router, brand, technologies, or wireless standards might help, how many APs, rough setup guidance — mesh, repeater, etc.), we’d be grateful for your input.

#RTK, UDP, Multicast, lots of concurrent low-bandwidth streams (several kB per drone), AP mesh

 

[Ralston18]

Security requirements?

 

[gafonator]

Security requirements?

Security is, at the moment, not a concern. Just classic WPA2.

 

[bill001g]

Do you actually use multicast. Multicast is very strangely implemented in wifi. It is kinda sent to a broadcast group since sending exactly the same data to multiple device all of which can actually hear the traffic being sent to the other device is kinda silly.

I have not looked at this in years. Multicast was never implemented on the internet where it would be great to reduce the bandwidth of live streamed data. Part of the reason is you can't really encrypt the data and you end up sending separate copies with the unique keys to each end device which defeats the purpose of multicast.

Since all wifi traffic is also now encrypted this makes all the strange issue with multicast on wifi even more complex. In effect it is not actually using multicast it is just sending data via UDP to each device.

In your application a better method would be to use broadcast and let the end devices pick out which messages are for them some where at the application level. You would also encrypt at the application level rather than at the wifi level to keep some silly kid from messing with your stuff. I would assume someone has already though about this. It would make the choice of wifi equipment much simpler and use much less bandwidth.

 

[gafonator]

Do you actually use multicast. Multicast is very strangely implemented in wifi. It is kinda sent to a broadcast group since sending exactly the same data to multiple device all of which can actually hear the traffic being sent to the other device is kinda silly.

I have not looked at this in years. Multicast was never implemented on the internet where it would be great to reduce the bandwidth of live streamed data. Part of the reason is you can't really encrypt the data and you end up sending separate copies with the unique keys to each end device which defeats the purpose of multicast.

Since all wifi traffic is also now encrypted this makes all the strange issue with multicast on wifi even more complex. In effect it is not actually using multicast it is just sending data via UDP to each device.

In your application a better method would be to use broadcast and let the end devices pick out which messages are for them some where at the application level. You would also encrypt at the application level rather than at the wifi level to keep some silly kid from messing with your stuff. I would assume someone has already though about this. It would make the choice of wifi equipment much simpler and use much less bandwidth.

Yup. I agree that it is a bit strange. But from what I understood, Multicast is used because as soon as you get many drones at once, the Unicast becomes unmanageable. How it is managed inside the devices themselves, I do not yet understand. Fyi, there are also GPS corrections being sent al the time.

The actual application layer is called RTK, but the whole thing goes somewhat deeper, the NTRIP protocl is as low as Layer 4 (OSI).

OSI Layer	Role in RTK context	Examples
Layer 7 – Application	Applications that generate or consume RTK corrections	GNSS receivers, RTKLIB, base station software
Layer 6 – Presentation	Data formatting, message types, encoding (RTCM protocol itself)	RTCM 3.x message formats
Layer 4 – Transport	Ensures delivery of RTK data streams over networks	NTRIP protocol

As for the "let the device choose...", I appreciate you taking time to think about it all, but I don't think we have another option — other than what the applications and control units themselves actually do (Ardupilot and Skybrush). At least not if we don't want to change the whole setup, from hardware to software, control units, etc. I guess...?

 

[cruisetung]

Not recommendation, just vendor claimed number I found on internet

AX1800 Indoor/Outdoor WiFi 6 Access Point

Powered by the latest WiFi 6 technology, the AX1800 Indoor/Outdoor WiFi 6 Access Point EAP610-Outdoor delivers WiFi speeds of up to 1.8 Gbps, ideal for use in outdoor environments, such as outdoor swimming pools, cafes, and amusement parks.

www.tp-link.com

200m for 2.4Ghz and 300m for 5Ghz

https://www.amazon.com/TP-Link-EAP610-Outdoor-Seamless-Multiple-Controller/dp/B0B231J81C?th=1

 

[bill001g]

https://www.amazon.com/TP-Link-EAP610-Outdoor-Seamless-Multiple-Controller/dp/B0B231J81C?th=1

The largest thing that would be a never buy this product is that it is "cloud managed". It likely can be configured manually but anything "cloud" is a security exposure.

Most the rest of it is your standard marketing guy speak. They can talk about coverage and antenna and everything else but that is only 1/2 the connection. They likely tested between 2 of their units rather than testing to a actual end device. I am sure they did not actually use QAM1024 at those distances. This encoding is extremely dense and wifi signals degrade exponentially with distance so these dense data encodings do not go very far. They of course do not every give any details on how and where they get their numbers from.

So called "seamless" roaming does not really exist since the end device not the network decides where to connect. Now they may load some software on the client, they have in the fine print that you need to use their controller which I assume is some kind of hardware device....or maybe it is a AI cloud based thing 🙁

This does not make this a bad product. Every single company is going to have this marketing speak in their ads.

Bottom line I don't know how you can tell which products would work well for this application. All the actual wifi chips they use are mostly made by mediatek or broadcom. I am not sure if qualcomm only makes end device chips or if they also make chips for router and ap. What this means is there is not a lot of difference between the brands. If you look at the chips they use they will have similar performance.

 

[cruisetung]

I believe the industry is quite competitive now.

View: https://www.youtube.com/watch?v=MRbBhBAv2dM

Build A DIY Drone Light Show | It's Not As Hard As You Think - Drone Dojo

No, you don't have to be a millionaire to make a drone light show. In this guide, I walk you through every step in the DIY drone light show process.

dojofordrones.com

Skybrush recommends the RT-AC5300 Asus router, so that is what we used.

But I think he did not mention exactly how many drones or the height he reached,

Setting up Skybrush for more than 250 drones - Skybrush Open-source Drone Show Software

Yes, Skybrush can handle more than one MAVLink network. Read on for more information.

skybrush.io