LoRa/LoRaWAN tutorial 11: Carrier Frequencies and Bandwidths
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- เผยแพร่เมื่อ 30 ก.ย. 2018
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This is part 11 of the LoRa/LoRaWAN tutorial.
In this video series different topics will be explained which will help you to understand LoRa/LoRaWAN.
It is recommended to watch each video sequentially as I may refer to certain LoRa/LoRaWAN topics explained earlier.
In this video I will discuss carrier frequencies, bandwidths, ETSI sub bands, dwell time and hop time.
As mentioned before LoRaWAN uses frequencies in the ISM band.
On The Things Network (TTN) website you can find the carrier frequencies for your country.
First find the frequency plan which applies to your country:
www.thethingsnetwork.org/docs...
For example:
Netherlands uses frequency plan EU863-870
If you know your frequency plan, find the corresponding LoRaWAN frequencies:
www.thethingsnetwork.org/docs...
Instead of using the The Things Network (TTN) website, checkout the LoRaWAN Regional Parameters document issued by the LoRa Alliance:
lora-alliance.org/lorawan-for...
This document contains the approved frequency channel plans for various global regions, and follows the established regulatory constraints in those regions.
In this video I am only focussing on the EU863-870 ISM band, for other ISM bands please consult the LoRaWAN Regional Parameters document.
If your country uses the EU863-870 ISM band, than according to the LoRaWAN Regional Parameters document every EU868MHz end device must implement the following default channels:
- 868.10 MHz, bandwidth = 125 kHz
- 868.30 MHz, bandwidth = 125 kHz
- 868.50 MHz, bandwidth = 125 kHz
and additional 5 frequencies.
The other 5 frequencies can be freely attributed by the network operator.
For example, The Things Network implemented the following frequencies: 867.1, 867.3, 867.5, 867.7 and 867.9.
Earlier the word channel is used.
A channel is just an agreed-upon set of specific frequencies with additional information included in the agreement.
For example when using the TTN freq. plan: EU863-870 the uplink channel 3 refers to:
- carrier frequency: 867.1 MHz
- SF7BW125 to SF12BW125
The LoRaWAN Regional Parameters used by The Things Network can also be found at:
github.com/TheThingsNetwork/g...
ETSI divides the 863-870 MHz band (referenced "G") into 5 sub-bands: G, G1, G2, G3 and G4. [5]
Each sub band has different constraints in term of EIRP, duty cycle and channel bandwidth.
LoRaWAN only uses the following bandwidth ranges: 125 kHz, 250 kHz and 500 kHz.
Which of these 3 ranges are actual used depends on the region or frequency plan.
For example in Europe only the bandwidths 125kHz and 250 kHz are used.
An end device changes channel in a pseudo-random fashion for every transmission.
Changing frequencies makes the system more robust to interferences.
For example in Europe for uplink transmissions 8 different frequencies are used.
Dwell time (or transmit time) is the amount of time needed to transmit on a frequency.
Hop time is the amount of time needed to change from one frequency to another in which the radio is not transmitting
Check out all my other LoRa/LoRaWAN tutorial videos:
• LoRa/LoRaWAN tutorials
Subscribe to my TH-cam channel:
/ @mobilefish
The presentation used in this video tutorial can be found at:
www.mobilefish.com/developer/...
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I have absolutely fallen in love with this series
Thanks so much for all of our videos! They are extremely helpful with my understanding of LoRa and LoRaWAN
I truly appreciate this video series, it's most informative. Reading other documents I thought that each message is transmitted up to three times, each time on a different frequency to guarantee that the GW receives the message. However, in this video, it seems to me that the message is sent just only once within some channel. When the device sends the next message, it does so using a different channel. There is no guarantee that every message is received, but chances are that some of them will arrive at the GW, aren't they? Sending each message three times would be a waste of the duty cycle.
Can i assume, that the LoRa modulation is FHSS (Frequency Hopping Spread Spectrum) too?
Thanks, Mr. Robert, If I cannot find any record in the frequency plan for my country IRAQ 😁, how can i work with Lorawan?
Thank you for the video! At 4:07 you show that the end device must implement the three default channels + 5 additional frequencies. I can't find anything in the regional document that says you must implement an additional 5 frequencies? The document says the JoinAccept can have an optional CFlist, and the example has 5 frequencies, but this appears not to be required?
Hi Jaco. I think you are right. I also could not find this in the documentation. I will update my presentation. Thanks!
I do like the graphics you use. Is there anywhere I can download them from? Thanks for the great tutorials.
All my presentations (pdf) can be downloaded from: www.mobilefish.com/developer/lorawan/lorawan_quickguide_tutorial.html
I couldn’t find my country in the listed frequency plans for differing countries. How can I implement LoRaWan deployment in my country in such situation or is there anything the alliance could help with?
do you know the ERP power value for LoRa & NB-IoT receivers?
How is ADR (adaptive data ate related to carrier frequencies?.When the gateway receives a signal ,then after calculation it tells which carrier frequency to choose ?..What determines on which carrier frequency to pick for transmission ?...Really confused here...Need help
I want to create a Lora mesh network on how to do with Lora? is it possible for Lora to work like a multihop?
8 or 9 uplink channels, do we use last channel with FSK modulation?
Hello sir. Your videos absolutely clear... But, you had shown at 6:20 "G sub band is between 863-870 MHz". After that, at 6:37, you showed that G sub band is between 867.1-867.9 Mhz. Is there any mistake?
How did you captured the Node transmission at different frequency spots ?
I used a cheap SDR dongle, see: th-cam.com/video/bSAa2aOXpCc/w-d-xo.html
What do u mean by download frequency and upload freq ? Is it reference to Lora node or Lora Gateway ?
In tutorial 22 i have demonstrated how a message is send from end node to gateway. These are uplinks. In my next video tutorial 25 I will demonstrate how to send messages from gateway to end node. These are downlinks.
In Europe is also possible to use the 433 MHz frecuency, isn't it?
At the frequency plan 250 KHz is at 868.3 MHz, however in the rest video 250 goes with 867.3 MHz. Is it a mistake? Btw, congratulations and thank you for your videos!
Please make a tutorial on chirp spreading spectrum
This will be my next video...
Hi there, I have a question... What if in Guatemala there is no specified Frequency plan?
Every country should have a frequency plan.
See: lora-alliance.org/sites/default/files/2018-04/lorawantm_regional_parameters_v1.1rb_-_final.pdf
Page 10
You have a mistake at 2.56 minute on your video, you said that on channel 1 SF7BW125 to SF12BW126 and SF7BW250, but you show this on graphic wrong at 6.46 minute the green region should be on 868.3 channel freq, am I true?
Muhammed, you are absolutely right! I have no idea why I have missed that!
I will immediately fix my presentation(s).
www.mobilefish.com/download/lora/lora_part11.pdf
Unfortunately I will not fix my video.
Again thanks!!!
i want to design lorawan. so, what i do right now for planing lora network?
Can you please share the slide pack used in your videos ?
All my slides can be found at: www.mobilefish.com/developer/lorawan/lorawan_quickguide_tutorial.html
I would like to ask if I'm using only LoRa modulation and not implementing Lora-wan I'm still committed
to LoRa WAN regulation?
By using the radio band, you must abide to the local regulations. (for example, in Europe, maximum of 1% duty cycle, maximum 14 dBm Tx power and so on). If you decide to join a community, as The Things Network, they have more rules that you have to take into account (maximum 30s transmission time from node to gateway, maximum 10 messages from gateway to node and so on).
Hi~
Does channel hopping occurs on the endpoint?
The transmitter does the channel hopping
Is it possible to tune Lora in a differente frequency?
When using LoRaWAN you can use different frequencies.
Which frequencies are allowed depends on your region, see:
lora-alliance.org/sites/default/files/2018-04/lorawantm_regional_parameters_v1.1rb_-_final.pdf
If you want to change the frequencies:
1) Change the libraries used by your end device (for example: lmic library)
2) Change the LoRaWAN Gateway parameters.
I do NOT recommend that you change the frequencies set in 1) and 2), unless you know what you are doing...
ATTENTION: If you send data to The Things Network (Network server), they are using these frequencies:
www.thethingsnetwork.org/docs/lorawan/frequency-plans.html
These frequencies also maps with 1) and 2)
Why there is provision of default channels ?
Sorry, I do not know.
Default channels exist to ensure that the device can use at least N channels in the frequency plan. The remaining channels are network dependent and may not match.
Sir i want use lora ra 01 & make 4 transmitter &1 receiver ,How to configure please guide