[PATCH] broadband-modem/libqcdm: use signal strength from QCDM EVDO Pilot Sets log messages

[Dan Williams]

On Tue, 2016-07-26 at 10:24 -0500, Dan Williams wrote:
> When a CDMA-only modem is registered with the EVDO network, its not
> possible to
> read signal strength in the following cases:
> 
> 1) while a data connection is active on single-AT-port modems,
> because the AT
> port is used for PPP and not available for AT+CSQ, AT+CIND or vendor-
> specific
> signal strength commands
> 
> 2) when the modem reports only CDMA 1x signal strength with AT+CSQ
> 
> Now that we have a reasonable interpretation of RSSI from the QCDM
> EVDO Pilot Sets V2 log messgae, use that when other means of getting
> signal strength aren't available.

If anyone's interested in the details and data for the HDR active pilot
energy to RSSI conversion, I've got a spreadsheet of it that I'm happy
to share.  And if you like math and statistics, please figure out a
better conversion formula from pilot energy to either RSSI dBm or ECIO
than I did.  It looks like there's either some logarithmic stuff going
on, or pilot energy may not account for noise which could increase the
range.  When I walked within LoS of a tower, the AT!RSSI results were
clearly excellent, but the pilot energy didn't jump quite as high as I
expected it to.  But the curves look related, so I'll take it :)

Dan