We have a customer in New Zeland that when he removes and attach the antenna on the modem, the modem wont reconnect to the network, the modem need to be rebooted to reconnect otherwise he has to wait a lot , we estimated like 10 to 15 minutes sometimes even more.
While debugging i’ve found that when removing the antenna the data connection state handler wont be notified real time.
Also when before the antenna get removed the signal quality is high , after removing and attaching the antenna we get very weak signal the radio state goes to LE_MRC_REG_SEARCHING
and, as i said before, we have to wait like 10 to 15 minutes or even more to get the modem reconnected to network.
I think this is an odd behavior for the modem and its a problem for us , because if i restart the modem it will reconnect right away, and we need the modem to be able to reconnect when we remove the antenna and attach it again.
We are on R14.1.1 , we updated from R11 which had the same problem and we thougth that R14.1.1 would resolve the issue
To isolate if this is legato problem, you can try at+cgreg=2 to see if there is any +cgreg unsolicited message after 15 mins
Also to totally remove signal, you need to put module into shielding box
we did some testing , removing and plugging the antenna a few times
this is the result , in the end the modem hang up in LE_MRC_REG_SEARCHING and the last report from +crreg is :
+CREG: 3
I feel this is a radio firmware issue - I have attached a test build of Release 14 which has fixed a similar issue for me. It’s too big to attach, and you can download from here.
You can still reuse your application built for R14 which should be compatible.
If you have more concern about managing the network attachment, there is an off the shelf free connManager comes with PyRTE
connManager Config Usage: e.g.: config set /apps/connManager/app/noRxDataTimeout noRegTimeout Specify timeout in seconds before reset radio for no registration, default 60 maxRadioRetry Specify max times of retry of reset of radio without registration, default 3 noRxDataTimeout Specify timeout in seconds before reboot for no receiveing traffic, default 900
then legato is in sync with the AT command response, probably not the legato issue, and when you receive +CGREG:2 , that means the module is still trying to reconnect to the network
Ok, but why does the modem connect almost instantly if rebooted? Why this does not happen when the modem lose the connection?
Is there any way of menaging the network more efficiently? Like @billzhou wrote about a connManeger that menages noRegTimeout, maxRadioRetry, noRxDataTimeout. I would like to menages this options myself in my app
The firmware includes a fix of dropping out from CAT M1 network. It can be the direct trigger of LE_MRC_REG_SEARCHING which is trying to register to the network option next to CAT M1. For FX30S with WP7702, the next option is 2G, and if you are using a SIM which doesn’t support 2G(e.g. Spark in NZ), it will take some time to timeout before switch back to CAT M1.
Well, this is all theory - your testing result shall verify it!