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Microcell parameters for ALU B10

Viewing 15 posts - 1 through 15 (of 23 total)
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  • #66131 Reply
    Ian
    Guest

    Hello Experts,

    We have Microcell in our Network B10 Alcatel.

    We have 80 to 85 % HO DL quality, meaning most of the hand-overs to leave the microcells are triggered in DL Qual; (HO_Level=-94)

    Theese microcells are supposed to HO to Umbrella layer on level but most of HO are triggered on Qual, and there are no interferences .

    I’m looking for a good set of parameters. (maybe with features MCHO)

    If anybody can help, that would be great.

    BR
    Ian

    #66132 Reply
    pix
    Guest

    hi ian,

    what are the settings for
    l_rxqual_dl_h
    l_rxqual_ul_h

    l_rxlev_dl_h
    l_rxlev_ul_h

    a_qual_ho
    a_lev_ho

    for your microcell ?

    thanks
    pix

    #66133 Reply
    Ian
    Guest

    Hi Pix,

    l_rxqual_dl_h=39 (*0.1)
    l_rxqual_ul_h=39 (*0.1)

    l_rxlev_dl_h= -97
    l_rxlev_ul_h= -97

    EN_MCHO_H_UL=enabled EN_MCHO_H_DL=enabled

    U_RXLEV_DL_MCHO=-93
    U_RXLEV_UL_MCHO=-93

    W_LEV_MCHO=1
    A_LEV_MCHO=10

    a_qual_ho= 4 (SACCH)
    a_lev_ho=4 (SACCH)
    w_lev_ho= 1

    I think by applying MCHO feature, it is not taking into account other parameters, i’ve been looking for an ALU doc but cant find any. Maybe you can help.

    BR
    Yann

    #66134 Reply
    Ian
    Guest

    Hi Pix,

    Do you see anyhting wrong with these parameters ?

    Do you know how MCHO works with ALU ?

    BR
    Ian

    #66135 Reply
    pix
    Guest

    hi ian,

    yes, i do know how MCHO work 🙂
    so i’m sure we will sort it out !

    first thing : whn you activate the MCHO handovers, they do not forbid other type of handovers to take place. They only activate 3 new causes (UL and DL and BAD SACCH) among all the others that already exist.
    IMO, the MCHO causes DL and UL are not useful and can be simulated by the typical “low DL” and “low UL” level HO causes.
    The cause BAD SACCH is more interesting and is tuned thanks to the parameter N_BAD_SACCH.

    1/ Deactivate MCHO DL and MCHO UL.
    2/ Apply these default settings;
    l_rxqual_dl_h=39 (*0.1)
    l_rxqual_ul_h=39 (*0.1)
    l_rxlev_dl_h= -93dBm
    l_rxlev_ul_h= -101dBm
    ho_margin(s,n) = 5dB in both directions
    Optimize this setting:
    a_pbgt_ho = 12, then 10 then 8 SACCH

    do you see any decrease of HO QUALITY ?

    What about HO INTERFERENCE ? Is it high ?

    Please post some real Qos readings for HO split, HO outgoing preparation sucess rate and HO efficiency rate, idle band measurements of the interference and the “RMS” rxlev_avg, rxqual_avg, timing_advance_avg for each TRX of that cell.

    Regards,
    pix

    #66136 Reply
    Ian
    Guest

    Hi Pix,

    I had tried these settings and we are not doing a lot of HO qual but we are doing a lot of Ping Pong between Macro and Micro.

    No Ho Interference.

    Is there any way to stop Ping Pong ? i know with other vendor you can set up a Penalty for Ping Pong.

    Do you have good settings using MCHO ?

    Thanks
    Ian

    #66137 Reply
    pix
    Guest

    hi ian,

    ping pong between micro and macro…

    micro to macro : those are emergency handovers, so i guess your signal quality in the micro cell is very bad.

    macro to micro : those are capture ho, the MS is sent to the micro cell because the rxlev of the microcell is good enough.
    what is your setting of L_RXLEV_CPT_HO(macro, micro) ?

    The anti ping pong timer is calle T_INHIBIT_CPT. Tune it to a high value in the macro cell (about 40s).It will prevent the capture ho from macro to micro AFTER the MS did a QUALITY HO from micro to macro.

    The main issue seems to be bad quality in the microcell, perhaps your capture ho is done too early.
    L_RXLEV_CPT_HO(macro, micro) ?
    A_PBGT_HO(macro) ?
    L_MIN_DWELL_TIME(macro) ?
    H_min_dwell_time(macro) ?

    Regards,
    pix

    #66138 Reply
    Ian
    Guest

    Hi Pix,

    values are :

    L_RXLEV_CPT_HO(macro, micro) ?
    Micro to Macro, -85
    Macro to Micro, -75

    A_PBGT_HO(macro) ?

    8 SACCH for Macro, 6 SACCH for Micro

    L_MIN_DWELL_TIME(macro) ?
    20

    H_min_dwell_time(macro) ?
    4

    Do you think these parameters correct ?

    Br
    Ian

    #66139 Reply
    pix
    Guest

    yes, those settings are correct.
    do you see a lot of quality ho in the micro cells ?
    regards
    pix

    #66140 Reply
    Ian
    Guest

    Hi Pix,

    Unfortunately yes, and we are doing Ping Pong HO.

    Dont know whats going on.

    As Microcell, looks like all HO are tiggerred within Emergency on DL QUAL ; no pbgt, no level; does it mean all HO leaving the cell are on QUAL ?

    BR
    IAn

    #66141 Reply
    pix
    Guest

    ian,

    it seems you have a real quality problem in your microcells.
    have you checked RMS ?
    – rxqual avg
    – rxlev avg
    – timing advance average
    – “s” average (radio link counter)
    – UL FER

    or just by doing a drive test, you’ll see where you’re having a quality issue. have you tried changing frequencies ? deactivate DL power control ? deactivate amr ?
    In your situation, the t inhibit will work very well, as i explained earlier… but it is just hidding the problem, not fixing it.

    cheers
    pix

    #66142 Reply
    Gaurav
    Guest

    Hi pix,
    I want to know about HO parameters how do they work???

    1.A_LEV_HO
    2.A_LEV_MCHO
    3.A_PBGT_HO

    Pls suggest…….

    #66143 Reply
    pix
    Guest

    those are averaging windows, used to average the last “n” SACCH measurement-results.
    Those averages are then used for HO decisions (= the raw measurements are useless).

    If A_lev_Ho = 4, it means that the value of rxlev used in algorithms is acctually the averages of the past 4 rxlev measuremed.
    There is one measurement every 480ms (= 0.5s), so it means that one avg_rxlev is an average of the past 4*0.5 = 2s.
    If a_lev_ho is too small, then averages are too ‘jumpy’. HO decisions are made on fake pikes or dives .
    If too large, then in front of a criticial loss of signal, the averages will not reflect the problem soon enough. The HO cannot be detected in time.

    Best Regards,
    pix

    #66144 Reply
    mannu
    Guest

    Hi Pix,

    Actually i am also working on ALU micro site and i faced one problem there is a lots of uplink quality handover happened in one of cell,actually there are two sectors in a site one is working fine and the other one has lots of uplink quality handover ,i checked frequency i checked TRX by shifting traffic one by one there is no alarm no hardware faulty but still i am not able to find the problem.
    will you help me on this topic

    #66145 Reply
    pix
    Guest

    hi mannu,

    Since when do you have interference in UL ? Since forever ? Or since a specific date ?

    When you swapped the two cells, does the problem occur on the same “physical sector” than before, or on the same “logical cell” than before ?

    If same physical sector – then you have a HW issue with the micro BTS. Check feeder connection and try to make a full restart of the BTS.

    If same logical cell – then you do have a configuration problem, probably due to frequencies. Could you swap frequencies from one cell to the other one?

    For each cell :
    * What is the HO UL Qual % in each cell ? (busy hour value)

    * how much is the TCH erlang BH traffic ?

    * how much is the “idle channel interference” ?

    * how much is the average timing advance ? (in NPO Indicator family – Radio Measurements -)

    Cheers,
    pix

Viewing 15 posts - 1 through 15 (of 23 total)
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