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Paging during SMS

Viewing 15 posts - 1 through 15 (of 17 total)
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  • #69393 Reply
    SK
    Guest

    Hello,

    Please let me know that during an SMS (when MS has been allocated an SDCCH and sms is in progress, not sent), Will MT Call (paging) be successful for that particular time or calling party will get the IVR ‘User busy/Not Responding’? If Paging would be successful, What is the logic ?

    #69394 Reply
    pix
    Guest

    hi SK,

    if the MS is using a SDCCH, it is NOT in idle mode. Therefore the MSC will NOT page this MS. There is no need for a paging.

    So that answers your question. Now what ha&ppens next, i’m not sure. Perhaps the MSC will re-use the current SDCCH of the MS in order to setup a call.

    Regards
    pix

    #69395 Reply
    SK
    Guest

    Hello Pix,

    Thanks for your reply but we have conducted thorough testing and the results were opposite (during SMS sending process, the paging was successful and almost 99% of the calls terminated successfully on the same MS which was used for SMS origination)…

    As per my knowledge, as long as the MS has not established an MM link/state with MSC during SMS sent phase, it would be unreachable (When there would be no CP_Data msg) and the paging would be failed; However, when there would be a MM state established between MS and MSC during SMS, at that time, the paging to that MS would be successful…MSC would use that link to page MS…

    Is this is the real scenario ? Please confirm. Actually we are more surprised on the 99% successful paging rate during SMS setup; practically, it should be 50 50… What do you say ?

    Regards,

    SK

    #69396 Reply
    pix
    Guest

    Hi sk,

    It’s quite difficult to find 3GPP references for such scenario, but now i understand your problem better. Thanks for correcting my previous post.

    Let me recap :

    (1) Before the MM state is established, the MSC must send the paging on the whole LAC. The paging should result as a failure on CN side.

    (2) When MM state is established, the MSC can send the paging to the cell directly, and “ping” the MS with the FACCH.

    Your problem is in the phase (1) : those failures are not seen during your tests. Keeping in mind that this phase is super-short (shorter than T3113), don’t you think the BSC will act as a “buffer”, and when the MS is finally in MM state, the BSC will properly route the paging onto the FACCH ?

    As long as T3113 is not expired in the MSC, the paging is not considered as failed. Usually this timer is about 3 seconds. That’s much longer than the SMS setup time.

    Or….

    maybe, the MSC retransmits a second paging after the first paging went unanswered. The second occurence should be successfull…
    In such case you should see a failure of the first paging occurence, but a success for the paging altogether.

    #69397 Reply
    SK
    Guest

    Hello Pix,

    Thanks for the reply. Let me add that we were checking the scenarios with quite long and detailed sms (sending an sms containing too much text; 5-6 sms in a single sms) just to prolong the sms setup time.

    My query was regarding the Paging Success Rate for Mobile Terminated Calls during Long SMS setup. Having the points 1 and 2 mentioned by you, it should be 50/50… But we were having almost 100%… How it’s possible ? Please explain.

    #69398 Reply
    pix
    Guest

    hi,

    my answer didn’t post… damned.

    Ok, basically, the size of the SMS does not influence the SMS setup time, which is the same whatever the length of the SMS.

    The SMS flow is :
    1/ Random Access from MS
    2/ Immediate Assignment from BTS
    3/ subscriber signalling (authentication, etc)
    4/ SMS sending

    Steps 1 2 3 are SMS setup, during which MS cannot answer to paging AND MSC is not aware how to reach the MS other than sending paging on the LAC. But MS is not listening to Pagings anymore.

    Steps 4 is when MS is known by the MSC at the cell level (MM state). If sending a long SMS, the step 4 is gonna last longer.

    Regards

    #69399 Reply
    SK
    Guest

    So what is your comment about the paging call attempts during the steps 1-4 of sms sending ?

    Please explain…

    Regards,

    SK

    #69400 Reply
    SK
    Guest

    Anyone can help please ?

    Thanks

    #69401 Reply
    pix
    Guest

    sk, hi what more do you want me to explain ?

    #69402 Reply
    SK
    Guest

    Hello Pix,

    I want to have the knowledge of success rate of incoming pages for call to an MS in SMS sending phase.

    #69403 Reply
    SK
    Guest

    Hello Pix,

    I haven’t got your reply… Please send again.

    #69404 Reply
    pix
    Guest

    it’s just below :

    23rd December 2013 (17:33 GMT)

    And further below also. I think we both managed to cover the topic quite extensively. Do you still need additional info ?

    #69405 Reply
    SK
    Guest

    Hello pix,

    Thanks and I am still unable to get my query from your message. Can you please help me regarding the success rate of paging calls to an MS (in sms sending process). Just to inform you that we have performed extensive testing twice in the city and each time, all 1000 calls to a busy MS (in SMS sending process) were successful…

    Can you please explain how is it possible ? As already explained by you, during SMS sending process (points 1-3), MS would be unreachable and paging would be failed. So why are we getting 100% successful paging ?

    Thank you !

    Regards,

    SK

    #69406 Reply
    pix
    Guest

    Sk,

    Ok, but what do you think happens in the MSC during the timer T3113 ?
    It’s probable the MSC is able to make the connection between the 1st paging and a MS in MM state half a second later. It is probable that the MSC will not consider the Paging as “failed”, but rather is able to connect the incoming call to the “SMS-sending” MS.

    IMO the key of the problem is that SMS setup time is much shorter than T3113.I don’t know how many times I repeated that already 😀 But I understand if this answer is not acceptable to you, but yet you didn’t explained to me why it’s not a reasonnable explanation.

    T3113 timer :
    “the MSC initiates the paging process by broadcasting a “paging request” message on the paging sub channel (IMSI or TMSI of the MS and its Paging Group) and starts timer T3113. (…) Upon receipt of the “Paging Response” MSC stops the timer T3113. If the timer T3113 expires and a “Paging Response” message has not been received, the MSC may repeat the “Paging Request” message and start T3113 all over again. The number of successive paging attempt is a network dependent choice.”

    regards
    pix

    #69407 Reply
    SK
    Guest

    Hello Pix,

    Thanks for your reply and I really appreciate your dedication and interest.

    If you recall, My query was regarding a long sms setup phase (MS busy for time greater than t3113 and time of sms sending steps 1-3 is quite longer), in that case, wouldn’t it be a paging failed case (Subscriber unable to reach) in scenario of No 2nd Paging enabled at MSC ? Please also tell me for the case if 2nd paging is enabled also.

    Actually, I am unclear because there is a difference of results seen in testing. We tested it ourselves in one area and almost half or 35% of paging attempts were failed during very long sms setup phase. Same we asked for another team in a different city and they gave us 100% successful paging results during long sms setup phase. The network settings and entity nodes are same in both areas. What I may conclude that the second area testing team may had not setup long sms but only short (empty sms, not enough to expire T3113)… What do you say ?

    That’s what, I need to know ?

    Thank you !

    Regards,

    SK

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