How to measure LTE attachment time?


#1

Hi all!
I expect to be able to measure rather accurately the attachment time of a EM7565.
Does it exist a way to do it via the SDK?
Thanks

Johann


#2

@johann,

No there is no API which gives you time to attach (like GPS TTFF).

Regards

Matt


#3

@mlw
that is not a good news…
Nevertheless, I found some structures which provides the following variables via the
* pCSDomain
* pPSDomain
* csAttachState
* psAttachState

But I did not find reliable information to make the distinction between them except that the last 2 ones seems to be used in callback function which is deprecated.
Do you know some places where it is possible to get documentation on it?
thanks in advance.
Johann


#4

@johann,

CS and PS and packet switched and circuit switched attaches, these are mainly applicable to 2G and 3G where voice/SMS went over CS and your IP connection go over PS. This just tells you the state of the unit when you ask it or you will be able to tell you this if you set a callback up when the state changes.

All of this is contained in the help files for the SDK (Module Network Access Stratum (NAS) - Struct servSystem). So are you trying to measure ho long the unit takes to attach to the network from power up as it is pretty quick if attaching to the same cell when it previously shut down, typically this will be even faster than it takes for the unit to enumerate to a given Linux system…

Regards

Matt


#5

@mlw,
thanks Matt for this detailed explanation, so those variables do not refer to what I expect to do so…
You are right I try to measure how long it takes to the modem to attach to the network not necessarily from power up but more exactly from the precise moment I put the SDK in a CONNECTED state, networks won’t provide the same quality of connectivity depending where the modem can be at one time… Then I need to record these attachement speed so as to monitor and established some statistic on it. Even if it take only some microseconds it is OK to know it.
I am not at all a specialist in telecommunication, but I can learn new stuff of course! And here what I miss the most is a clear documentation on this device, a chance to get your responses.
If you know some books or whatever I could study and do to get this working I will get it for sure.
Johann


#6

@johann,

The state of the unit with regards layer 3 messaging can change on a mS to mS time frame so performing this sort of measurement is a bit difficult when using tools that are not specifically designed to do this, you can engineer tests/operations to do this and average out delays/network variances.

Re books/references, unfortunately it it is down to experience and an understanding of how the networks work so there is no magic text you can refer to.

Regards

Matt