Impact of TX power and RSSI

RE: Impact of TX power and RSSI

Simonr — Thu, 07 Jul 2022 08:45:28 GMT

Do you need RSSI or something similar in your application? For testing you should set the devices up in a control environment and make sure that the packets are transmitted and received at a satisfactory success rate. Using a receiver that acknowledges and prints out the transmitted data so you can see. If you get the expected data at 0dBm TX power there's no need to use 4dBm in your application. The environment you describe shouldn't require more than 0dBm in my experience.

Best regards,

Simon

RE: Impact of TX power and RSSI

TilakL — Wed, 06 Jul 2022 13:11:28 GMT

Thank you Simon for your detailed comments. The range is expected to be in a typical indoor environment where the assets can move and can experience shadowing effects with people moving around or constantly shadowing the line of sight communication.

As RSSI does not seem reliable, please suggest suitable alternatives to RSSI.

RE: Impact of TX power and RSSI

Simonr — Wed, 06 Jul 2022 12:54:33 GMT

First off, you shouldn't base too much off of the RSSI values you see, as these will only give an indication of what the sensitivity is, and not be very accurate. I would recommend testing that you receive the expected data at the range you're looking for instead of basing your tests off RSSI alone. As I don't know what your application/ use case is, I'm not sure what to recommend. What range is the application going to operate in, and in what kind of environment?

1. Yes, you will get worse RSSI values when decreasing the TX power, but if you're still happy with the effective range you get at 0dBm this should be fine. The RSSI will vary a lot depending on what environment you're testing in, so I can't come with an expected RSSI number I'm afraid.

2. I think this is just random as RSSI is not too reliable for measurement. I'm sure if you do the same test again the highs and lows will be different.

3. I can't speak for what the customer base is using, as everyone must choose what fits their specific use case. Some use +4dBm, some use 0dBm, and some use -40dBm. By default most of our example projects are set to 0dBm at least, to give good range as well as good power consumption results.

4. If you find that the higher dBm helps your transmissions/connection be more stable at the range you need them in, and power consumption does not matter as much, +4dBm could be a useful setting.

Best regards,

Simon