+KCELL=1 Signal strength vs $CSQ

Hello,

We’re using +KCELL=1 on the HL8548 to get information about neighboring towers. We’re interested in getting the physical channel power for each tower, similar to what we can retrieve with the $CSQ command.

Based on the AT Guide (version 19), GSM towers return RSSI which is an offset of -110 dBm. Is the resulting value equivilent to the physical channel power from $CSQ?

For UMTS towers, $CSQ returns Ec/No in addition to rssi. Is my understanding correct that in order to get physical channel power, we need to do (rssi * 2 - 113) + Ec/No ?

Similarly, for UMTS on KCELL, there is an rscp and ecno value, but they appear to have different ranges than the same in $CSQ. How do we calculate physical channel power from these values in KCELL?

Thank you,
Lennon

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As an additional observation, I’ve noticed that there are times where $CSQ returns a value just fine, but the rscp value from the KCELL call is defaulted to 255 for all towers (including serving). I see this behavior frequently when signal is low, but still good enough to transmit data via tcp. Is there anything I can do to make sure I get an rscp from KCELL?

Hi Lennon,

To get the rscp, maybe you can try +KNETSCAN(Network Scan)?
AT+COPS=2 //deregister from network
AT+KNETSCAN=1,1 //activate network scan, enable URC
//Wait some seconds to get the URC like below
+KNETSCAN: 2,49,42,64f000,247c,1448,5,48,55,64f000,247c,13ed,5
+KNETSCAN: 2,10663,64f010,a52a,d9fe179,432,19,39,10688,64f010,a52a,d9fe17a,432,14,39
AT+KNETSCAN=0 //deactivate network scan
AT+COPS=0 //auto register to network

So are you saying we shouldn’t be using KCELL? In what situation would we use one versus the other? We’re ultimately using this as part of a location calculation.

Are you able to help with any of the questions in my first post?

Thank you,
Lennon

Matt replied in another thread about the return value on KCell indicating missing data (especially on 2G). Is this related here as well and requiring the +KCELLSCAN?