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LoRa vs 2-FSK, comparision

Semtech Transceivers
#1

Hi,

I am trying to compare LoRa with FSK in terms of transmission speed and receiver sensitivity. When setting both LoRa and FSK to a comparable effective bit rate, around 600 bits per second, according to datasheets, LoRa achieves a receiver sensitivity of -132 dBm, whereas FSK has a sensitivity of -125 dBm. However, the advantage of FSK, if I understand correctly, is its much narrower bandwidth. While LoRa uses a bandwidth of 125 kHz, FSK requires only 4 kHz. Therefore, my question is how practical are these 4 kHz and how many channels could theoretically be placed side by side in a 125 kHz bandwidth so that they could operate in parallel with the stated sensitivity of around -125 dBm. Is it possible to compare this in some way? Theoretically, we could have up to 30 channels of 4 kHz in a 125 kHz bandwidth, which would mean the ability to communicate on approximately 30 times more channels simultaneously?

I am also interested in the opposite setting - setting the modulations so that they have the same RX sensitivity. If I do this and the surroundings are not interfered with by any other signal, can I expect communication over the same distance with both LoRa and FSK modulation?

Thank you for any reason.

#2

You could tranmit them but the how would the receivers be able to seperate channels that are so close together ?

There can be bleed through from strong LoRaWAN signals on adjacent channels and they are 200khz apart !. To seperate radio channels that are 5khz apart suggests you would need an exceptionally selective reciever.

Before you go any further with this theoretical exersize, maybe do some practical real world tests as to the minimum channel spacing FSK signals would support.

#3

Yes, I understand. I asked somewhat rhetorically to explain the problem I am addressing, and before I start experimenting, I wanted to know a realistic estimate of how many channels can fit into the bandwidth specified by the standard ETSI 300-220 … BW is 250kHz