Timeline: 3:05 Bandwidth vs Range 5:30 Radio Propagation - Link Budget (how much power we have between TxRx) 7:26 Free Space Path Loss 10:36 Sensitivity 12:40 Example: LoRa Link Budget 14:25 Wireless reach in reality 16:20 Multipath: reflected signal reduces signal strength 19:17 Fresnel zone 22:10 Two-ray model instead of FSPL (with testing scenario) 22:27 Summary 25:34 Antennas 29:15 Antenna Buy & DIY Taoglas Barracuda 31:03 What can you do to improve the range? 32:25 SODAQ balloon flight 34:07 LoRa Modulation - characteristics 40:05 LoRa Demodulation 43:17 Spreading Factors 45:15 Benefits of LoRa CSS 47:10 LoRaWan scalability 48:10 Adaptive Data Rate(ADR) mechanism 49:06 ISM bands
Dear Thomas, I really liked your presentation. You have the talent to explain this technology in a very very clear way. I am somebody who likes to understand as much as possible, and therefore was this presentation a joy to listen too. I have recently read some articles in the Elector magazine about LoRa, but problem there is that the articles are very very poor regarding a clear explanation. One small remark: the part where you explain the demodulation, you can add the Y-axis notation to the graph, to make clear the different 128 symbols are actually different 128 (base) frequencies, you later distill by FFT/DFT.
Thank you for the great video. But i have to add that you may have to take in consideration the atmospheric absorption for free space path loss. Its not a huge effect for these frequencies and these distances. But the total range depends on the medium properities which has a strong relation with the rf wave frequency.
Thank you very much for the video! Really helped clear up a lot of points about this technology! In addition, this knowledge (besides being interesting) should really help with correctly placing my gateway antenna!
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Highly interesting. Before that I didn't know what fresnel was all about. The transmitting mechanism (chirps) is also impressive, what gets developed. My team mates should learn what LoRa is, as they are getting into the IoT thing thing :-)
Fresnel field is the area near the aerial that is not uniform. Further way it is more uniform and predictable - that is my understanding. That is why EMC tests and checked in a open field with the aerials further apart then the fresnel region (roughly speaking).
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
At 44:58 in the viedo To to get different spreading factors, the only thing that changes is the speed of the chirp. The slower it goes, the more chips per symbol sent. Is that a CW carrier that's being shifted or is there modulation on the carrier?
There is modulation on the carrier. The novel thing about spread spectrum and there are others like frequency hopping is that the carrier moves and the carrier is modulated. Please correct me if I have misunderstood that?
Yes ... Frequency Hopped Spread Spectrum may be a single-sideband or FM signal and the carrier frequency hops as it goes through its hopping sequence. Bluetooth can learn that some frequencies are being used and not transmit on those. Direct Spred Spread Spectrum modulates the entire signal with a spreading code by "chipping" it. Essentially, the same bit gets sent over and over again. The resulting signal is wider than its original and thus "spread". On the receive side, the chipping sequence is re-applied to the signal and the data bits are recovered. Chirp Spread Spectrum is a lot like DSSS. It spreads the signal with a chirp sequence. The chirp starts at a position relative to the bit being sent. The chirp completes one cycle and then sends the next bit in the message. At the receive side, the chirping sequence is re-applied to the signal and the bit being sent is recovered. It now makes sense to me.
Although it is said that if two packets were to clash - that are using the same channel at the same time that one of the packets will be received. I suspect that both or many packets could get through because although the packet is spread by the chirp over the channel it is only using a small part of that channel at any one time (how small depends on the bandwidth set by SF) That is because the base station has many receivers and each receiver can recieve many packets at the same time - 8 receivers capable of receiving 48 total. I am guessing a bit.
Can someone recommend me some source of information about basics of chirp modulation? For example how a chirp is actually defined, I'm aware of up/down-chirps, how many times a chirp can be cyclicly shifted, does a single chirp can pass the same frequency twice, and also how many chirps are there per second used by lora and what does this depend on?
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Could you please elaborate on that point a little more? and is it that the sensitivity goes way down below -20dBm above SF12, that's why we take that as an upper bound?
Sorry I do that I do not know that is why I asked the question and made a suggestion? I did not do any programming to find out. I just read what I needed in the data sheets so that I could do the electronic design.
I do not think it matters just follow the advice and it should work very well in a field but will still be limited in built-up areas. The video says that and it is correct.
Thanks for your clear explanations. A little help: In the Fresnel Zone Radius calculation the formula is 8.656 √ d / f (d = distance in Kms and f = frequency in Gigahertz). Square root is not present in the slide, nor the unit for frequency. Best regards !
Timeline:
3:05 Bandwidth vs Range
5:30 Radio Propagation - Link Budget (how much power we have between TxRx)
7:26 Free Space Path Loss
10:36 Sensitivity
12:40 Example: LoRa Link Budget
14:25 Wireless reach in reality
16:20 Multipath: reflected signal reduces signal strength
19:17 Fresnel zone
22:10 Two-ray model instead of FSPL (with testing scenario)
22:27 Summary
25:34 Antennas
29:15 Antenna Buy & DIY Taoglas Barracuda
31:03 What can you do to improve the range?
32:25 SODAQ balloon flight
34:07 LoRa Modulation - characteristics
40:05 LoRa Demodulation
43:17 Spreading Factors
45:15 Benefits of LoRa CSS
47:10 LoRaWan scalability
48:10 Adaptive Data Rate(ADR) mechanism
49:06 ISM bands
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Dear Thomas, I really liked your presentation. You have the talent to explain this technology in a very very clear way. I am somebody who likes to understand as much as possible, and therefore was this presentation a joy to listen too. I have recently read some articles in the Elector magazine about LoRa, but problem there is that the articles are very very poor regarding a clear explanation. One small remark: the part where you explain the demodulation, you can add the Y-axis notation to the graph, to make clear the different 128 symbols are actually different 128 (base) frequencies, you later distill by FFT/DFT.
Thanks a lot for this greate video!
Excellent presentation! Thank you very much
I finally understand why CSS is able to have such great narrowband interference rejection. Thanks!
I think the Bastille link has much more detail if it is the video I watched a while back.
Geweldig Thomas, tnx
Nice and clear presentation. My compliments.
Thank, that was some Jedi level presentation.
Nice info, thank you for sharing it with us, keep it up :)
Fantastic job. Thanks for a great explanation.
Brilliant explanation of the LoRa basics. Many Thanks!
Thanks for a very clear presentation with a lot of well explained information. Thank you!
Thank you for the great video.
But i have to add that you may have to take in consideration the atmospheric absorption for free space path loss. Its not a huge effect for these frequencies and these distances. But the total range depends on the medium properities which has a strong relation with the rf wave frequency.
He touches on that with the 9dB for 2.4GHz but does not say that is -9dB. So you have a point.
Thank you very much for the video! Really helped clear up a lot of points about this technology! In addition, this knowledge (besides being interesting) should really help with correctly placing my gateway antenna!
brilliant. keep it up.
Very useful crash course, thanks Thomas
Thanks for the great information on LoRa
I really enjoyed the informative presentation and could find answers to my questions. Thanks a lot.
Outstanding presentation !! Thank you !
Great presentation. Really well thought out. Thank you!
Greetings sir !
Whether LoRa Is a multi point or point to point protocol
As lora cant transmit audio.but see LAP e01 device.it transmit voice over lora..how? Which module they used?
Very good primer, well worth watching
Thanks for the Webinar. Learned a lot.
Excellent video but why when we increase the spreading factor we increase the range. What is the relation ?
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Thanks Thomas! Lots of information!
Great presentation. Thanks for sharing so clearly
Highly interesting. Before that I didn't know what fresnel was all about. The transmitting mechanism (chirps) is also impressive, what gets developed. My team mates should learn what LoRa is, as they are getting into the IoT thing thing :-)
Fresnel field is the area near the aerial that is not uniform. Further way it is more uniform and predictable - that is my understanding. That is why EMC tests and checked in a open field with the aerials further apart then the fresnel region (roughly speaking).
Excellent intro to LoRa, thanks!
Hey Thomas! Enjoyed the presentation. I hope your are doing well.
2.4Ghz wifi frequency is having more FSPL compare to 868Mhz LoRa ?
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
At 44:58 in the viedo To to get different spreading factors, the only thing that changes is the speed of the chirp. The slower it goes, the more chips per symbol sent. Is that a CW carrier that's being shifted or is there modulation on the carrier?
There is modulation on the carrier. The novel thing about spread spectrum and there are others like frequency hopping is that the carrier moves and the carrier is modulated.
Please correct me if I have misunderstood that?
Yes ... Frequency Hopped Spread Spectrum may be a single-sideband or FM signal and the carrier frequency hops as it goes through its hopping sequence. Bluetooth can learn that some frequencies are being used and not transmit on those.
Direct Spred Spread Spectrum modulates the entire signal with a spreading code by "chipping" it. Essentially, the same bit gets sent over and over again. The resulting signal is wider than its original and thus "spread". On the receive side, the chipping sequence is re-applied to the signal and the data bits are recovered.
Chirp Spread Spectrum is a lot like DSSS. It spreads the signal with a chirp sequence. The chirp starts at a position relative to the bit being sent. The chirp completes one cycle and then sends the next bit in the message. At the receive side, the chirping sequence is re-applied to the signal and the bit being sent is recovered. It now makes sense to me.
Although it is said that if two packets were to clash - that are using the same channel at the same time that one of the packets will be received. I suspect that both or many packets could get through because although the packet is spread by the chirp over the channel it is only using a small part of that channel at any one time (how small depends on the bandwidth set by SF)
That is because the base station has many receivers and each receiver can recieve many packets at the same time - 8 receivers capable of receiving 48 total. I am guessing a bit.
Can someone recommend me some source of information about basics of chirp modulation? For example how a chirp is actually defined, I'm aware of up/down-chirps, how many times a chirp can be cyclicly shifted, does a single chirp can pass the same frequency twice, and also how many chirps are there per second used by lora and what does this depend on?
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Really informative. Many thanks.
Excellent thanks
What is LoRa Sync Word for?
Hi there! Please check out our Forum, a place where you can browse through questions that have already been answered or ask any new question you might have: www.thethingsnetwork.org/forum/
Very nice lecture. Thank you.
Hi sir, can you explain me why the spreading factor of the modulation is only between 7-12?
I wondered that - I suspect it is bit numbers in a register perhaps?
SF6 is no LoRa but simply FSK.
Could you please elaborate on that point a little more? and is it that the sensitivity goes way down below -20dBm above SF12, that's why we take that as an upper bound?
Sorry I do that I do not know that is why I asked the question and made a suggestion?
I did not do any programming to find out. I just read what I needed in the data sheets so that I could do the electronic design.
No problem sir, thank you for the help, will get back to you if I find an answer.Thank You
I do not think it matters just follow the advice and it should work very well in a field but will still be limited in built-up areas. The video says that and it is correct.
Nice job guys!
Thanks !!
Very Helpful!
Very well, thanks a lot!
What regulatory document states that max allowed antenna gain is 2.15dBi?
Very helpful. Thanks.
thanks for good information
Nice presentation, can i download this presentation?
many many thanks
Thanks for your clear explanations. A little help: In the Fresnel Zone Radius calculation the formula is 8.656 √ d / f (d = distance in Kms and f = frequency in Gigahertz). Square root is not present in the slide, nor the unit for frequency. Best regards !
that was crystal clear
slide download link?
Thx
Any one hot a link to the other talk he mentioned? Tks
Portuguese subtitle ?
48.46 adr
Excellent presentation! Thank you so much.