Spurious communication failure HSDPA

Posted on 2008-11-18
Last Modified: 2013-12-27
I have 50 HP iPaq 614c devices, with a custom developed Compact Framework 2.0 application.
The application has been running for 3 month sucessfullly.

Last week, I started receiving deviced where communication failed.

Typical scenario is that the device establishes HSDPA communication and starts to transmit and receives data, all good. But then after a various amount of minutes of inactivity on the line, the device cannot transmit again.
"various amount of minutes" because it varies on different weekday and daytime, but typically 4-5 minutes.
Though last friday evening, and all sunday, we had no problems, otherwise it is always around 20-25% of the devices that are failing.

To resolve the transmitting flaw, we turn off the phone modem and turn it on again. Pushing the reset button will also do the trick. This will force the device to establish a new connection.

I talked with out provider, and they state that sometimes the devices tries to connect without a valid APN.
But I have checked the setup on several devices failing, and the HSDPA settings are correct. (And it is only sometimes)

So currently I do not know what and how to troubleshoot this flaw.
I would like to be able to monitor in- and outbound HSDPA communication from the device?
I would like to hear your advice?
Perhaps my application is build wrong?

The application is business critical, so I'm currently quite f..ked

A little info on the application....
It communicates with a reliable webservice. The application has a webservice proxyclass, that is created as a singleton in the main thread of the application upon initialing. (Have tried creating a new instance of the class for each call, without any difference)
Each call to the proxyclass is queued in a seperate thread. Eg...
Main thread (typicaly a form):
StateHandler sh = new StateHandler()
sh.HeartbeatPostback += new HeartbeatEventHandler(heartbeatPostBack);
ThreadPool.QueueUserWorkItem(new WaitCallback(st.Heartbeat));

public void Heartbeat(object state)
  // Call service proxy
  bool hasHeartbeat = WebserviceProxy.Instance.GetHeartbeat()
  // raise event when services replies
  RaiseHeartbeatPostback( hasHeartbeat )
Question by:tarasbredel
    LVL 1

    Expert Comment

    I work for a network provider in the UK (O2) and I am pretty sure that this violates our "Fair use" policy (FUP), I am also pretty sure that there are a lot of people in the call centers that won't have a clue what your on about and don't realize that you are breaking the FUP.
      The server which the APN is connecting to might be kicking you off automatically when you have been using it excessively, it may even do it randomly (EG I know that they randomly boot people off who are on skype ports as this breaks the FUP!) Phone the call center again ask for someone who has a in depth knowledge of the FUP.

    Author Comment

    Hi James

    Thanks for your response!
    I spend a few hours last week, just to get through to the technical expertise at my provider. (Phew their call center is persistent in not forwarding calls to the techies)
    We had a long discussion, I where stubbern, claiming that their resent upgrades to the network, must have caused these issues (it had been working for several month).
    After going through our usage , he found nothing suspicious, but then he stubled upon a trace indicating that some of our subscriptions where sending blank APN's and after that, he simply refused that their network had any flaws... "It has to be the iPaq, or perhaps Windows Mobile causing it..." end of discussion!

    Futhermore I cannot se how we should violate the FUP. We do not have an excessive use....
    When the connection is established, we have 3-4 transmissions, a total of about 35-40 KB.
    The next (and last) transmission is 3 hours later, and is around 30-35 KB. Thats it.

    LVL 1

    Expert Comment

    Ahh ok I doubt that will violate the fup, what you may want to try and do is to back up your device and perform a hard reset (factory settings), as much as i love my current WM6.1 device I have already had to do that once all ready and my previous WM6 and WM5 devices where always having to be hard reset to sort out the problem.

    Author Comment

    Been there, done that... (a million times)
    I'm currently experiencing this issue with 50 iPaqs. (bwt. WM 6.0)
    I've even tied to upgrade .net framework from 2.0 SP1 to 3.5
    I have tried to installed the latest firmware (though it is only suppose to be a bluetooth driver update)

    A techie is going to call me today, so that we can run a trace... hope it gives some answers
    LVL 1

    Expert Comment

    Might not be the answer you are looking for try another network provider in a device and give that a shot, also ask google if your network regally drops packet data.

    Author Comment

    I have considered it as an option...
    The techie called today, and has was able to setup a trace, though only on 2G communication. He setup the trace for an hour, while I made all kinds of tests. I logged all activities, events and exceptions on the device and sent him a complete history.
    He will get back tomorrow after analyzing it all.... I'm excited to hear his response!
    LVL 1

    Expert Comment

    Any joy?

    Author Comment

    just talked to him... havn't found anything yet... will get back monday...
    LVL 1

    Assisted Solution

    Good Luck!

    Accepted Solution

    just got his answer.... "here are the 4 .pcap files from the trace. Feel free to contact we if you have any futher questions!"

    In other words... he's done nothing, but letting me wait for a week, and then he sends me the wireshark files. Hmpf
    Guess I need to find a wirehark expert, because I'm not capable of debugging it.
    There is just to many things I don't understand... you would happen to....?
    Thank you!

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