GPS tracking with LoRa


(LoRaTracker) #21

What calculations have you done to ensure that your plan is;

A. Legal
B. Within the fair access policy of TTN


(tlu) #22

I think there a number of people, including me, who are struggling to comprehend what TTN mean by ‘fair access’. It seems that someone is allowed to run as many nodes as they like that comply with the ‘fair access policy’ but if one individual node exceeds the policy the owner is somehow a bad person. I don’t see the distinction between one device running a DC of 2% versus two devices running a DC of 1% each, because both are consuming the same airtime. Please explain.


(DarkMan) #23

tlu, I agree. plus the video and all that got me in lora promised whole bunch of things… like firmware updates over air that last for days… where was that fair access policy then. I whish there was one fair access policy with wifi back then ;D

Still I will do it fair from start, as much as I can.

LoRaTracker, it’s legal.
Fair is suggested and considered.


(LoRaTracker) #24

Interesting, are you able to share the calculations ?


(DarkMan) #25

O I thought about frequency and such. Like I said, I’m here to get advices on how to do it and what’s best practices. Calculations comes next. Surely if it’s not legal in 1 in 30sec it will be 40 or 60 … Don’t really care in this stage.


(LoRaTracker) #26

Probably best to to assume that a lot of messages will end up towards the SF12 end especially if the ‘public transport’ is in a City with few gateways.

A navigation payload at SF12 will take about 1.25seconds air time so around 24 messages a day. if that is enough to track the public transport then the project would be good to go.


(LoRaTracker) #27

The fair access policy is clear enough.

If you dont agree with the policy for TTN as a free to use system, then maybe look at alternatives.


#28

LoRaTracker,

What do you mean when you ask “is it legal”. LoRa falls within the ISM band, as long as the “radio” falls within the specifications of the country its used.

Darkman, I see you’re using the TBeam too, great little tracker.

We use 3G trackers for buses, vehicles, trucks instead of LoRawan network.

We will have LoRa environmental sensors on the bus to measure temperature, humidity, air quality, UV light and upload the data 2-4 times daily.


#29

59%20AM

19%20AM

Trailers with 3G trackers. We will eventually add LoRawan environment sensors which are “peel and stick” installed, collecting env data along their routes.


(LoRaTracker) #30

Do the transmissions, possibly at the worst case scenario, stick to the 1% duty cycle limit, common to most countries.

Which at SF12 would be a minimal position message around once every 125 seconds.


#31

Ok, you meant fair access.


(LoRaTracker) #32

Er no, I meant legal.

Fair access and what is legal are different.


#33

Got it. Thanks for sharing.

I see you’ve tested the SX1280, great to know Semtech makes a WIFI version for LoRa, will be a great fit with https://www.ui.com/products/#default


(LoRaTracker) #34

Indeed so, and whilst 2.4Ghz is shorter range, there are no duty cycle restrictions.

Unfortunatley the hardware interface to the SX1280 is completly different to the SX127x, so none of the software for TTN nodes or single channel gateways will work.


(Jac Kersing) #35

See https://www.thethingsnetwork.org/forum/t/limitations-data-rate-packet-size-30-sec-up-and-10-messages-down-p-d-fair-access/1300

The 1% you are referring to is a legal limit (at least in EU), exceeding that means your use will be illegal and your local authorities might fine you.
Why limits for each device and allowing multiple devices? Probably because it is much harder to write rules when multiple devices are involved. However I did not write the rules so I don’t know the reasoning.

Keep in mind LoRaWAN can not scale if everyone starts using 1%, even if it is legally allowed. With a radio that can be heard 15km away and might well cause interference 15km away you can’t behave the same as with for instance WiFi which can’t be received 100m away (with normal antennas).
Because LoRaWAN (in EU) has no listen before talk everyone using 1% would result in massive packet loss well before there are 100 nodes on that channel (using the same spreading factor). Where a well designed network with friendly users scales to multiple thousands of nodes for a gateway, when looking at the limits (1%) you will run into issues at (guestimate) 400 nodes transmitting 1% of the time. And at that time other users of the same frequencies will also suffer (as in be unable to use those frequencies).


#36

(DarkMan) #37

Well, that escalated quickly :smiley:
I’m sure in future we’ll have massive interference as three national networks (as I know) are starting and they will do thousands of devices in one city. But, I think 433 and 900mhz are also legal in EU so…
I certainly will respect air time limits.
Does anyone have any practical example in some town using LoRa?
Btw. what about “always on” nodes… for example only location on demand? Would that be better than just sending info always?


(LoRaTracker) #38

Fair access policy limits packets to the node, i.e a request for the node to send information, to 10 messages per day.


(Kimwo) #39

Hi Darkman - I see you have set up a nice 4 gateway network in Sibenik. Lovely
area I have sailed in several times. Which prompts a suggestion - the chartplotters
are set up only to plot a GPS position when you have moved xxxx metres. This
would be a good way to avoid redundant messages for your transport application.

Of course you could sell nodes to the marina, set up geofences and only sent a message once a day, or when they are stolen. Now that would definitely be within the fair use policy!


(DarkMan) #40

Hi kimwo. First, thanx :slight_smile: second, good idea,… I could use checkpoints mode only for city transport to get within policy rules.