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Repeated FACH/SACH

Viewing 15 posts - 16 through 30 (of 41 total)
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  • #67043 Reply
    VanG
    Guest

    Hi Pix,
    I tried to activate the Rep_SACH/FACH and TFO/AMR_FR for all cells in diferent BSCs …
    Please advise me how to (with which indicators) check quickly, whether everything is OK or not?
    My other question is is there any relation between parameter _FACCH_LEGACY_SUPPORT and TFO success rate, because I saw that when I changed it from 1 to 0 there is impact to the TFO_Success rate..
    Best regards,

    #67044 Reply
    pix
    Guest

    hi vang

    repeated facch – better outgoing ho efficiency rate
    repeated sacch – less call drop rate “amr”

    that would be very visible in cells where usage of lower codecs is high. This usage can be assessed through RMS indicators.

    could you tell me what is your subset of codecs AMR FR ?

    The repeated FACCH or SACCH should not have any impact on TFO.

    TFO with AMR… there should be an increase on the number of TFO requests in your network. I don’t know what are the names of the indicators, but all the ones which contain the string ‘TFO’ will definitely reflect the change.

    There should be more AMR codec changes, as a result. So here again, you might see such effect in the RMS.

    regards
    pix

    #67045 Reply
    VanG
    Guest

    Hi Pix,
    thank you for your help..
    I will check this idicators..
    About the codec for AMR_FR we use 4,75/5,90/7,4/12,2 kbps.
    Best regard,

    #67046 Reply
    VanG
    Guest

    Hi Pix,
    After these changes, there are some cells with inceased CHO_DL/UL_quality. Did you have any idea what can be the reasons?
    Best regards,

    #67047 Reply
    pix
    Guest

    vang,

    could you post the values for all the “ho qual” indicators

    L_RXQUAL_DL_P*
    L_RXQUAL_UL_P*

    there might be about 6 or 8 altogether.

    regards
    pix

    #67048 Reply
    VanG
    Guest

    Hi Pix,
    this value for cells with inrceased CHO_DL/UL_quality:

    AMR_FR_THR_1(dB)=5
    AMR_FR_THR_2(dB)=10
    AMR_FR_THR_3(dB)=13
    KEEP_CODEC_HO=free choice of the codec
    L_RXQUAL_DL_H_AMR=4.5
    L_RXQUAL_UL_H_AMR=4.5
    L_RXQUAL_DL_P_AMR_RXACCH=(2(SFH); 3(No SFH))
    L_RXQUAL_UL_P_AMR_RXACCH=(2(SFH); 3(No SFH))
    A_LEV_HO(SACCH)=6
    A_QUAL_HO(SACCH)=6
    EN_RXQUAL_DL=TRUE
    EN_RXQUAL_UL=TRUE
    HO_INTRACELL=FALSE
    L_RXQUALDLP=2
    L_RXQUALULP=2

    Best regards,

    #67049 Reply
    VanG
    Guest

    Hi Pix,
    what do you think about my settings?
    Best regards,

    #67050 Reply
    pix
    Guest

    hi vanG,

    In those cells, could you check the indicators related to repeated SACCH ? do you see a high amount of calls with RSACCH activated ?

    In such cells, AMR calls are more protected and are less prone to interference. In other words, even if RXQUAL is bad, the voice and the SACCH are still holding. So I would consider increasing the HO QUAL thresholds (L_RXQUAL_DL_H_AMR and UL_H_AMR) to 5.5 and the PC thresholds “L_QUAL_*_AMR_RxACCH” to 3.5.

    I’m surprised that your SFH PC Thresholds are higher than non-SFH. That should be the opposite.

    All my advices are based on the inputs you gave me, which are extremely little. So if that doesn’t work, I can’t be held responsible 🙂

    regards
    pix

    #67051 Reply
    VanG
    Guest

    Hi Pix,
    thank you for your help and recomendations..
    About the “Calls with SACCH” active, in the comparisons between GQSCCN and GSDRSACN, the half of calls are with RSACCH activated.
    I tried to change the L_RXQUAL_DL_P_AMR_RXACCH to value “3” for the cells with SFH, but nothing changed..
    If you need more information or parameters value, ask me which :))
    What do you think about EN_TFO_OPT, because I was tried to disable but again nothing and what should be value for “ADD_HR_IN_TFO_LIST”?

    #67052 Reply
    pix
    Guest

    hi vang,

    the tfo should not influence the rxqual of the call, so that’s not where we should be looking at first.

    i would love to have more inputs :
    – what is the increase in the ratio and numbers of HO QUAL UL & DL (separately) ?
    – what is the evolution of the RTCH Drop Rate in one of those cells.
    – have you tried increasing the L_RXQUAL_DL_H_AMR and L_RXQUAL_UL_H_AMR (= not the PC but the HO thresholds), I suggested that in my previous post.

    Regards
    pix

    #67053 Reply
    VanG
    Guest

    Hi Pix,
    these are the values of CHO_Quality 10days before and 10 after AMR_FR/TFO/RepSACCH activation on one BSC in my region:
    BSC_xx AVG_10days_before AVG_10days_after
    CHO_DL_quality_rate(GHCSTEQLDR)(%) 0.43% 0.54%
    CHO_UL_quality_rate(GHCSTEQLUR)(%) 0.30% 0.80%
    CHO_quality_rate(GHCSTEQLR)(%) 0.72% 1.34%
    As you see there the CHO_Quality increased but I can not find reasons..May be my settings are not correct:((
    About the changes of L_RXQUAL_DL_H_AMR and L_RXQUAL_UL_H_AMR, today I will try to change for some “HOquality increased” cells and give you information on monday…
    Best regards,

    #67054 Reply
    pix
    Guest

    hi,

    ok, it is a very small increase. maybe the calls are not dropping anymore, but instead they do a HO. Did you notice a decrease of TCH Drop Rate ?
    In your BSC indicators table below, could you add the “Call_Drop_Rate” ? instead of the average 10 days before / after, could you do the average of the 10 busy hours of the 10 days before and after ?
    Frankly, your changes are so small that it might just be a statistical effect. Have you checked those 10 days before and after ? I guess in 10 days you might have only one week-end during the “before” period and two week-ends during the “after” period. So that would definitely bias the average values… That’s just a thought 🙂

    Regards
    pix

    #67055 Reply
    VanG
    Guest

    Hi Pix,
    I tried to disable AMR_FR for one of the affected cells and from yesterday untill now the HO_UL_quality are decreased approx from 30/per hour to 1/per hour..
    May be the problem with UL quality HO comes from my settings for AMR_FR?
    Other question, if is it possible:))
    Is there some parameter or setting when is used TMA in cell?
    I ask you because we install TMA for one cell and we observ that the UL interferences are increased..

    #67056 Reply
    pix
    Guest

    vanG,

    your problem with the UL Quality HO is very interesting ad would like to help you more, but unfortunately I would need to truobleshoot it by myself: do drive-tests, check NPO and run some tests on parameters.
    I have no clear idea on what should be checked, there are many things that pop to my mind.
    First I would do a drivetest and check that the codec mode changes are taking place, and measure the UL RxQual for that call (if you can trace it ?). Try to understand for which codec the UL RxQual degrades. In RNO, the RMS measurements about AMR could give you a good overview too. Maybe you can share those vectors & matrices here ?

    RMS_AMR_UL_FR_BadSpeechFrames
    RMS_AMR_UL_FR_Codec_sample 
    RMS_AMR_UL_FR_RxLevel_sample 

    Just drag n drop those indicators one by one to the bottom panel, for a day for which AMR FR was activated.

    I’m don’t know how useful will be the results, but well…

    Regards
    pix

    #67057 Reply
    VanG
    Guest

    Thank you Pix,
    I will check it and give you feedback…
    BR,

Viewing 15 posts - 16 through 30 (of 41 total)
Reply To: Repeated FACH/SACH
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