LTE_LC_RRC_MODE_CONNECTED timeout

[allard.p]

I've the following situation:

1. Send CoAP message trough send(), this causes the the nRF9160 to start RCC connection

2. Wait for RCC connected mode (LTE_LC_RRC_MODE_CONNECTED)

3. Start CoAP retransmit timers

Two questions:

- Is it possible to 'force' RCC connection without sending something trough a socket?

- What would be a reasonable timeout for step 2? I tried to extract this from the 3GPP TS 38.331 document, but I did not find the timeout.

[Achim Kraus]

> What would be a reasonable timeout for step 2?

Depends on you requirements. I use 60s. In many cases, it's about 2-3s, in rare cases up to 15s, in very rare cases it was up to 60s. My consideration was, that the very rare cases left for the 60s don't cost too much energy, because the 15s will almost be enough. And for the very rare cases I decide to go for "works" instead of " save energy". I didn't made the experience, that after the 60s it moves to RCC Connected in a couple of seconds, so there I wait for longer until I retry the whole. I don't stop the modem, but I also don't retransmit the coap-message and fail the request instead.