Electronic – Highest achievable datarate for sub-1GHz wireless

sub-1wireless

According to this datasheet, Semtech LoRa can reach 9375 kbps, while CC1125 from TI has a maximum datarate of only 200 kbps, despite both operating on the same frequency (868/915). To reach its highest datarate, LoRa must be used with it's lowest spreading factor, and CC1125 uses narrowband transmission, so the it seems to me that the difference in datarate should not be so great, and especially that it should be higher for CC1125.

What are the key factors I should look into to better understand what datarates are possible for sub-1GHz systems, and thus better evaluate the available systems (bandwidth/spreading/modulation/protocol/etc)?

Best Answer

This is a error in the application note. In the table of page 22, between the SF10 line and the SF9 line, the decimal dot was lost. The table should read:

LoRa SF = 9 -> 1.757 kb/s or 1757 b/s
LoRa SF = 8 -> 3.125 kb/s or 3125 b/s
LoRa SF = 7 -> 5.468 kb/s or 5468 b/s
LoRa SF = 6 -> 9.375 kb/s or 9375 b/s

The LoRa modulation is perfect for low and medium data rates, but cannot be used at high data rate. That why Semtech transceivers support LoRa AND FSK/MSK/OOK, to offer a full range of data rates (and be able to interact with legacy systems).

Related Topic