What is the relationship between RSSI and datarate?

RE: What is the relationship between RSSI and datarate?

Ziyao Zhou — Mon, 10 Mar 2025 11:04:40 GMT

Thank you for your information!

RE: What is the relationship between RSSI and datarate?

Edvin — Mon, 10 Mar 2025 09:49:06 GMT

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

RE: What is the relationship between RSSI and datarate?

Ziyao Zhou — Sat, 08 Mar 2025 13:51:39 GMT

[quote userid="26071" url="~/f/nordic-q-a/119596/what-is-the-relationship-between-rssi-and-datarate/526373"] I will look into your other ticket.[/quote]

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?

RE: What is the relationship between RSSI and datarate?

Ziyao Zhou — Sat, 08 Mar 2025 01:19:11 GMT

Thank you for your information!

RE: What is the relationship between RSSI and datarate?

Edvin — Fri, 07 Mar 2025 14:37:26 GMT

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.

[quote user="Ziyao Zhou"]As the C = W log₂(1+S/N) b/s, here[/quote]

This is above my knowledge on the topic, unfortunately.

Best regards,

Edvin

RE: What is the relationship between RSSI and datarate?

Ziyao Zhou — Fri, 07 Mar 2025 00:59:50 GMT

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.

[quote userid="26071" url="~/f/nordic-q-a/119596/what-is-the-relationship-between-rssi-and-datarate/526212"]In general, lower RSSI doesn't affect the datarate,[/quote]

RE: What is the relationship between RSSI and datarate?

ketiljo — Thu, 06 Mar 2025 16:07:53 GMT

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.

RE: What is the relationship between RSSI and datarate?

Ziyao Zhou — Thu, 06 Mar 2025 15:04:48 GMT

Thank you for your information. Yes, I am talking about BLE. Could you please check this ticket, does the change means packet loss?

By the way, I am thinking about tune the RSSI to have the target data rate. Do you think this is feasible physically? Is high RSSI a sufficient condition for high Datarate?

RE: What is the relationship between RSSI and datarate?

Edvin — Thu, 06 Mar 2025 15:01:28 GMT

Hello,

Are we talking about the datarate in a Bluetooth Low Energy (BLE) connection here?

In general, lower RSSI doesn't affect the datarate, but if you are lowering it enough, so that you will start getting packet loss, then this will again trigger retransmissions of the packets, and this will of course affect the total bandwidth, giving you a lower data rate in the BLE connection.

I don't know if this answers your question.

Best regards,

Edvin