What is the relationship between RSSI and datarate?

[Ziyao Zhou]

Hi,

Recently I am studying the relationship between RSSI and datarate. Intuitively, I think lower the RSSI lower the datarete. Is there any physical evidence for this guess,Are they causal or correlated?

I have done some experiments in this ticket, specifically, I notice my two experiments shows different behaviour, but all the enviroment is identical, so could you please clarify me about the relationship between RSSI and datarate?

[ketiljo]

RSSI is not related to the datarate at all. RSSI is a measure of the power of the recived signal and will vary with output power, antenna gain and distance only.

[Ziyao Zhou]

Hi,

Thank you for your information!

Can I say that for a specific environment, the noise level is stable, the RSSI is highly related to the data rate. As the C = W log₂(1+S/N) b/s, here the SNR can be tune by increasing transmitter power.

Another question is in my experiment, when the distance become longer, the current will drop. And I consider this to be the packer loss. If it correct, then lower RSSI affect data rate a lot. You may kindly check this ticket.

Edvin said:

In general, lower RSSI doesn't affect the datarate,

[Edvin]

Just to be precise, the RSSI doesn't affect the datarate on air, but it may affect the throughput if you start seeing packet loss. And packet loss is a common thing, and it is increased with more noise, or longer distances, or in other words, a lower Received Signal Strength (indicator). I will look into your other ticket.

Ziyao Zhou said:

As the C = W log₂(1+S/N) b/s, here

This is above my knowledge on the topic, unfortunately.

Best regards,

Edvin

[Ziyao Zhou]

Thank you for your information!

[Ziyao Zhou]

Edvin said:

I will look into your other ticket.

Hi，

If in certain range the RSSI will not effect the datarate before reach the RX sensitivity. Why this ticket has such behaviour? Thank you so much for your time?

[Edvin]

I wrote some more details in the ticket that you linked to:

 High datarate current consumption change a lot when changing distance 

Best regards,

Edvin

[Ziyao Zhou]

Thank you for your information!