Wireless network modules for ~50 clients sending 2-4kbps each over 1km square.  - Page 1
Forum section: electronics / projects

author: Jackster
author_rank: Frequent Contributor
timestamp: March 10, 2024, 02:23:16 am
content: Have a project where I have about 50 GPS sensors sending out location data and some other telemetry data.Expecting a transmission rate of around 2-4kbps for each client as we need a polling rate of around 10-20Hz.The aim is to have as low latency as possible with each poll.There will be a broadcast (to all clients) from the base station so needs to receive ~5kbps.Ideally one does not want to reinvent the wheel so I am looking for radio modules that could handle this sort of usage.Needs to have TDMA scheduling or other multi-user handling so we don't end up with noise.The range is around 1km from the base station max.Probably looking at the 2.4GHz frequency so it can be deployed anywhere. This being outdoors and mostly away from built-up areas, I don't see it being an issue.That being said. While WiFi sounds like a great option, I would prefer a solution where we can just set up a single base station with little to no config for the end user. Multiple base stations might be required on some sites. Each base station will also have a GPS in it for RTK correction (part of the 5kbps broadcast) and an LTE modem so the data can be fed back to the central command. So custom housing is already required.LTE is not an option for each client either.This is just a concept project for something else I have in the works (a hobby project).Am I overthinking it?

author: Psi
author_rank: Super Contributor
timestamp: March 10, 2024, 02:32:42 am
content: NiceRF have a collection of radio modules that I've used before.They have a store on albaba and on aliexpress

author: whollender
author_rank: Regular Contributor
timestamp: March 10, 2024, 04:40:07 am
content: Sounds like a good application for lora

author: jc101
author_rank: Frequent Contributor
timestamp: March 10, 2024, 09:55:25 am
content: The Wurth Thyone-I modules might be a solution, they can operate as a mesh too.Unicast, broadcast and multicast all supported - with unicast there are automatic retries and it informs you if the receiver didn't get the packet.They may send you a couple of dev kits to have a play with.I've used the Setebos-I modules, as they can be set to run either in Wurth proprietary mode as a Thyone-I module or with Bluetooth 5.1 like a Proteus-III module.Note with these when you change a setting, apart from RF channel, that is stored into flash - which has a limited life. So use a read before changing a setting. Once setup there shouldn't really be a need to change anything though.

author: Jackster
author_rank: Frequent Contributor
timestamp: March 10, 2024, 10:57:52 pm
content: Quote from: jc101 on March 10, 2024, 09:55:25 amI was actually looking at their Themisto and Thebe modules the other day."10-20km" range. I will contact Wurth about it and see what they think.Wurth also looks to have Wirepas stuff. That company has some interesting mesh networking technology including some new "5G" stuff on 1.9GHz.If it can handle the latency and throughput, their offering might be perfect. Hopefully, the licensing is not too bad.

author: Jackster
author_rank: Frequent Contributor
timestamp: March 12, 2024, 04:01:28 pm
content: Wirepas got back to me. Way too much data for their system.I guess it is fine for periodic data but sending 2-4kbps per client is way out of spec for IoT.

author: uer166
author_rank: Super Contributor
timestamp: March 12, 2024, 04:32:26 pm
content: Quote from: whollender on March 10, 2024, 04:40:07 amI think this is too much BW for lora. 2-4 kbps x50 clients is 100-200 kbps on the base station. Unless you have a LoRa chipset per client operating at different frequency from everything else, not sure how you'd accomplish that.Might want to look into HaLow Wifi, but the latency will probably be hard to control.

author: vidarr
author_rank: Frequent Contributor
timestamp: March 12, 2024, 04:43:17 pm
content: It could be done with ESP32 and LoRa, but that would be ridiculous. We built a mesh network using that in my neighborhood, but I am telling you, it is not worth it.Just use WiFi. Everything is already done for you. Leave the network open and use a simple SSID. Add APs as necessary. There are millions of tutorials and videos about this. It doesn't get any easier.edit: Also, you can find routers at almost all resale stores (Goodwill, Salvation Army, etc.). Last time I was in the USA, I bought a bunch of them for $5-10 each (and they were most recent units --not outdated crap).

author: Jackster
author_rank: Frequent Contributor
timestamp: March 12, 2024, 05:12:14 pm
content: Quote from: vidarr on March 12, 2024, 04:43:17 pm

author: bookaboo
author_rank: Frequent Contributor
timestamp: March 12, 2024, 05:19:25 pm
content: The Brazilian gentleman took time out of his day to give you a pointer to something you can't figure outSomething he's achieved by himself.Just saying.

author: Jackster
author_rank: Frequent Contributor
timestamp: March 12, 2024, 05:58:50 pm
content: Quote from: bookaboo on March 12, 2024, 05:19:25 pmPretty sure he is having a laugh with the two points I put in bold...The only real solution when it comes to WiFi is either enterprise deployment of APs or HaLow.That is not to say a single AP pre-setup is out of the question.. If needs must, a few APs with zero handoff, WiFi 6/7 would work well.But I am hoping for a lower frequency, higher range solution to already be out there.

author: LaserSteve
author_rank: Super Contributor
timestamp: March 12, 2024, 09:27:44 pm
content: In the past I've used Laird Connectivity...Steve

author: ejeffrey
author_rank: Super Contributor
timestamp: March 13, 2024, 12:56:01 am
content: Quote from: Jackster on March 12, 2024, 05:58:50 pmYou said:Quote