Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages

PS Inter-RAT HO

Viewing 14 posts - 1 through 14 (of 14 total)
  • Author
    Posts
  • #67603 Reply
    mXa
    Guest

    Dear All,

    Can u give ur opinions on pros & cons of enabling/disabling 3G to 2G handovers in PS domain ?

    mXa

    #67604 Reply
    pix
    Guest

    hi,

    i didn’t know the PS Handovers already existed in 2G. Which vendor is it ?

    I don’t see any cons, but I assume it requires a good tuning of parameters so that RNC and BSC can communicate.
    the pros is that there is no interruption of the PS transfer while the MS is moving from 3G to 2G. A reselection would take about 2s to 5s to complete, during which the transfer is stopped.

    regards
    pix

    #67605 Reply
    mXa
    Guest

    Pix,

    Sorry, I was in a hurry and didn’t explain the problem quite well. U r right, there is no HO between 3G and 2G. What I meant is the SGSN context transfer between both SGSNs after RA request.

    Now, is it favorable to:
    -keep MS on 2G after reselection & open the way for another 3G reselection when conditions are better?
    -keep MS on 3G and don’t perform 2G reselection?

    Regards,
    mXa

    #67606 Reply
    pix
    Guest

    hi !

    ok, now it makes more sense 😉

    i’d favour going to 2G when the 3G coverage starts to be too low. You don’t want to extend your 3G coverage beyond its nominal cell range. Indeed, that would generate more noise for every other 3G user.

    So I would activate the 3G-2G reselection in PTM mode, just before it is too late.
    I guess you already actiavted this reselection in Idle Mode ?

    And of course, activate it the other way around, but with enough hysteresis to avoid ping pong reselections…

    (I know it all sounds very theoretical, but finding the perfect solution for you would require drivetests and extensive stats analysis…)

    #67607 Reply
    mXa
    Guest

    I am working with this current setup but here comes the question. And yes, reselection in idle mode is enabled.

    – Having heavy 3G data usage will send u to 2G most of the times.

    – Will u start with 3G and get most of the time transferred to 2G? because even making aggressive thresholds will allow more users to use 3G data which will lead to same result eventually.

    – Keep the MS on 3G but in case of heavy data usage, MS won’t have a good HSDPA throughput (because 3G penetration increased). However, this will still be better than 2G experience in terms of throughput.

    Know what i mean?

    mXa

    #67608 Reply
    pix
    Guest

    hi,

    I’m not sure I understand. Could you explain what you mean by

    “Having heavy 3G data usage will send u to 2G most of the times.”

    Thanks

    Pix

    #67609 Reply
    mXa
    Guest

    By heavy user traffic,I mean something like BH traffic.

    So, 3G cell would shrink and Inter-RAT scenario to be considered.

    mXa

    #67610 Reply
    pix
    Guest

    hi,

    it sounds like you have a great test scenario that you should do with a drivetest 🙂 With qoS stats, I’m sure you could assess how badly the 3G is while it is loaded (looking at reselection %, coding scheme used, etc)

    IMO if the 3G is so bad that the MS reselects the 2G, even with the most aggressive thresholds, then be it. But that has to be verified on the field.

    Regards
    pix

    #67611 Reply
    Kamal
    Guest

    hi,
    no more pros & cons at all…!!

    Only few thresolds & proper configuration @ sgsn..

    We have implemented PS HO from 3G to 2G in network sharing..!!

    We don’t have 3G spectrum so using other operator’s plmn for 3G…!

    in this EPLMN,we are doing fine PS ho..

    Regards,
    Kamal

    #67612 Reply
    Niraj
    Guest

    Hi Kamal,

    Can you please share the required definitions at SGSN end.We are facing issue with 3G-2G PS HO.The cell order chage message we are getting but after GPRS suspension requestPDP context is being activated in 2G and after that it comes under Standby mode.Speed becomes zero and we needto switch off the phone again to use data services.

    Regards,
    Niraj

    #67613 Reply
    Ayat
    Guest

    Hello
    My question about the formula

    We have two formula for inter rat ps handover umts to gprs
    1 is ps inter rat outgoing success / attempts
    AND the other vendor using cco
    Cell change request to define
    Inter rat ps outgoing ho to gprs

    So we have to work with one kpi formula ?
    Which one is reflect the right value for ps ho ?

    #67614 Reply
    LEMAURE
    Guest

    Hello Ayat,

    you should better use the first formula as it is based on 2G neighbor measurements (real HO) whereas cell change is rather reselection/redirection which in fact doESn’t need neighbors to happen; therefore is not assimilated to HO

    #67615 Reply
    Ayat
    Guest

    LEMAURE
    Actually i have read a lot of docs about thi since long time , and i think CCO is seamless handover
    But cco no need to resouecse reservatuon before ho
    Our formula only consider cco procedure and ps inter rat ho is zero
    Also 3gpp docs define ps inter rat umts to gprs as cco

    #67616 Reply
    pix
    Guest

    hi Ayat,

    CCO is not a handover : resource is not reserved beforehand, network doesn’t know that mobile is changing cell, and mobile has to do a standard (full) setup on the target cell.

    It is possible to perform a real PS HO from 3G to 2G, involving a procedure which is specified in 3GPP
    as “IRAT HO”. Alternatively it is also possible to use the CCO to perform mobility from 3G to 2G. Both procedures exist, and the operator has to choose whether or not to activate PS HO.
    Activating PS HO will (mostly) replace the CCO.
    Most operators I know do not activate PS HO, in order to avoid compressed mode during PS transfer. They’d rather let the PS transfer continue until the drop. Since it is “bursty”, there are very high chances that the transfer will be over before the drop.

    So yeah, back to the point, you can define the KPI for mobility PS 3G to 2G based on CCO and/or PS HO, whichever one is used.

    Cheers
    pix

Viewing 14 posts - 1 through 14 (of 14 total)
Reply To: Reply #67610 in PS Inter-RAT HO
Your information:




<a href="" title="" rel="" target=""> <blockquote cite=""> <code> <pre class=""> <em> <strong> <del datetime="" cite=""> <ins datetime="" cite=""> <ul> <ol start=""> <li> <img src="" border="" alt="" height="" width="">