LoRa/LoRaWAN tutorial 10: RSSI and SNR

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This is part 10 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 explain what RSSI and SNR are.
The Received Signal Strength Indication (RSSI) is the received signal power in milliwatts and is measured in dBm.
This value can be used as a measurement of how well a receiver can "hear" a signal from a sender.
The RSSI is measured in dBm and is a negative value.
The closer to 0 the better the signal is.
Typical LoRa RSSI values are:
RSSI minimum = -120 dBm.
If RSSI=-30dBm: signal is strong.
If RSSI=-120dBm: signal is weak.
Signal-to-Noise Ratio (SNR) is the ratio between the received power signal and the noise floor power level.
The noise floor is an area of all unwanted interfering signal sources which can corrupt the transmitted signal and therefore re-transmissions will occur.
If SNR is greater than 0, the received signal operates above the noise floor.
If SNR is smaller than 0, the received signal operates below the noise floor.
Normally the noise floor is the physical limit of sensitivity, however LoRa works below the noise level.
Typical LoRa SNR values are between: -20dB and +10dB
A value closer to +10dB means the received signal is less corrupted.
LoRa can demodulate signals which are -7.5 dB to -20 dB below the noise floor.
Check out all my other LoRa/LoRaWAN tutorial videos:
• LoRa/LoRaWAN tutorials
Subscribe to my RU-vid channel:
/ @mobilefish
The presentation used in this video tutorial can be found at:
www.mobilefish.com/developer/...
#mobilefish #lora #lorawan

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27 сен 2018

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Комментарии : 29

@Kenrro 3 года назад

Loved the end of the video! Looks awesome! Thank you!

@LAKXx 2 года назад

Very informative and most of all well explained! Thanks

@bartk174 2 года назад

Nice !

@Venaber 7 месяцев назад

good video

@JohnDavis_NetSkink_Computing 3 года назад

Nice videos. Thanks. What is the tool you are using to show the radio frequency activity?

@mikebeshay952 5 лет назад

any recommendation for a filed tester to test and know where is the best spot I should install my Lora GW/Sensor? and what is the best RSSI/SNR I should target?

@diegocomin8914 5 лет назад

So what is the difference between the Rx sensitivity and RSSI? What of both concepts I need to focus in order yo choose a LoRa device?

@21471adnan 4 года назад

Hi there..What is the SINR and CIR ?..What threshold does lora has to successfully differentiate between the signals ?

@vengeancead823 5 лет назад

sir, i want to ask about how to converting RSSI 0-255 value to dbm?

@bumusay 4 месяца назад

How can you demo them? What application that you using can simulate them...?

@saeedmagsi6288 3 года назад

Hello Sir. Thank you very much for uploading such an excellent tutorial. I have a question that how can we calculate received Power from RSSI. Do we need to add RSSI and SNR which will be equal to received power? or what is the method?

@hamiltonqrn2734 Год назад

The received power is the RSSI.

@Telectronics 2 года назад

Is there a function to read the RSSI and SNR when I send between two lora modules? I would like to show it on a display.

@pwrmx24 Год назад

I read an article it's possible to calculate relative position to 2 or three gateways (or nodes?l using time distince of arrival and rssi. The hateways talk to each other and compute the relative postion through triangulation the (or lat / long if the gateway has gps). The end point doesn't need to send any data really....just an ID or number. Anyone do this?

@oscargomezf Год назад

Hi sir. What is the name of the software you are using to hear LoRa signals?

@juanda1520 Год назад

please help sir how to get the rssi value of lora ebyte e22

@abdulrahmanmohamed31 2 года назад

thank you for your videos i learned a lot from them, i just have a question. i cant really wrap my head around SNR first of all you said that lora works under the noise floor level.. so making SNR values below 0. but then you say that typical lora SNR values are -20 to +10. but +10 makes it above the noise floor level. then it is said that lora cant de-modulate signals above -7.5 db below the noise floor. can you please elaborate what im missing here ? thank you for your help

@IslanderJerYT Год назад

Hey, I got a little confused with this too, but re-watched the video and I think I get it now. +10 would be ideal, but I guess this isn't always possible, however LoRa is able to operate at negative SNR values, and is subsequently able to demodulate signals between -7.5 and -20 dB from the noise floor. My guess is that if the signal strength is too close to, or specifically too close to and below the noise floor, the signal will not be demoldulatable.

@zaidahmad2701 5 лет назад

I am surprised how a useful signal can be received if it is below noise floor.

@youngkevinsmith 3 года назад

Is -120 DBM the lowest rssi that lora will work at?

@hamiltonqrn2734 Год назад

About -137 dBm in some configurations.

@GTA5NFT 2 года назад

Can I hire you for a project

@thexray_5d 2 года назад

So going by that, my signal should be good RSSI: -22 SNR: 11.5

@asvanfiirizky8439 5 лет назад

How do you get the lora data signal?

@Mobilefish 5 лет назад

Using a SDR, see: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bSAa2aOXpCc.html Using Cubic SDR software: cubicsdr.com/ And applying a trick. I make sure the message is send with SF12.

@arya8431 3 года назад

so what is good SNR value? >0 or

@Mobilefish 3 года назад

Signal-to-noise ratio (SNR) is defined as the ratio of the power of a signal (meaningful output = Pout) to the power of background noise (meaningless or unwanted input = Pin). SNR can be either positive and negative value if you represent it in dB scale. Negative SNR means that Signal power (Pout) is lower than the noise power (Pin). dB = 10 Log(Pout/Pin) Good: SNR > 0 Bad: SNR

@arya8431 3 года назад

@@Mobilefish thanks for explanation