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Immediate Assignment Problem

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  • #66900 Reply
    Vicky_RF
    Guest

    Hi All,

    Pls help to find the correct problem & solution:-
    Problem:-When doing the drive test MS A(Calling party)gets nothing(no alerting) but the MS B (called party) gets the miss call for a very short duration & same time TEMS shows blocked call (whereas layer 3 message shows “NO IMMEDIATE ASSIGNMENT” or “MISSING IMMEDIATE ASSIGNMENT” what does it mean. As cell is under utilized.
    For further more info pls….

    Pls help
    Thanx in advance

    #66901 Reply
    pix
    Guest

    hi vicky,

    the MS A could not get the immediate assignment. It means that the cell “A” suffers SDCCH Congestion. There is no other reason for cell A to not allocate a SDCCH channel.
    Check your qos Stats : SDCCH blocking or SDCCH Congestion.

    You should activate the “Immediate assignment reject” feature, that will help increase the stats.

    regards
    pix

    #66902 Reply
    Vicky_RF
    Guest

    Thanx Pix,

    Actually this feature is already been activated & also there is no SDCCH Blocking or SDCCH congestion.And from MSC side I am getting RAB assignment failure message.

    #66903 Reply
    Vicky_RF
    Guest

    Layer 3:-
    MS1
    System Information Type 3

    Time : 10:35:45.42
    Vendor Header
    ARFCN : 594 (GSM 1800)
    L2 pseudo length : 18
    Skip indicator : 0
    Protocol discriminator : (6) Radio resources management messages
    Message type : 27
    Cell identity (CI) : 13441 (Hex 0x3481)
    Location Area Identification
    Mobile country code (MCC) : 405
    Mobile network code (MNC) : 027
    Location area code (LAC) : 101 (Hex 0x0065)
    Control Channel Description
    MSCR : (1) MSC is Release ’99 onwards
    Attach/detach allowed (ATT) : (1) MSs in the cell shall apply IMSI attach and detach procedure
    BS-AG-BLKS-RES : 2
    CCCH-CONF : (2) 2 basic physical channels used for CCCH, not combined with SDCCHs
    CBQ3 : (0) Iu mode not supported
    BS-PA-MFRMS : 2 multiframes period
    T3212 timeout value : (15) 1.5 hours
    Cell options (BCCH)
    Dynamic ARFCN mapping indicator (DN-IND) : (0) Dynamic ARFCN mapping is not used by the PLMN
    Power control indicator (PWRC) : (0) PWRC Not set
    DTX indicator : (1) The MSs shall use uplink discontinuous transmission
    RADIO-LINK-TIMEOUT : 44
    Cell selection parameters
    CELL-RESELECT-HYSTERESIS : 14 dB Rxlev hysteresis for LA-reselection
    MS-TXPWR-MAX-CCH : 0
    ADDITIONAL RESELECT PARAM IND (ACS) : (0) System information type 16 and 17 are not broadcast on the BCCH
    HALF RATE SUPPORT (NECI) : (0) New establishment causes are not supported
    RXLEV-ACCESS-MIN : 8
    RACH control parameters
    Max retransmission : (2) Maximum 4 retransmissions
    Tx-integer : (12) 20 slots used
    Cell bar access : (0) Not barred
    Call reestablishment : (0) Allowed
    Access control
    Emergency Call allowed : (0) All MSs
    Barred classes :
    Rest Octets
    Selection Parameters
    cbq : 0
    Cell reselection offset : (5) 10 dB
    Temporary offset : (1) 10 dB
    Penalty time : (0) 20 s
    System Information 2ter indicator – Not Available
    Early classmark sending control – Explicity accepted
    BCCH scheduling is not sent in SI9
    GPRS indicator
    RA color : 0
    SI13 position : (0) SI13 message is sent on BCCH Norm
    Neither UTRAN nor CDMA2000 classmark change message shall be sent with the Early classmark sending
    SI2QInd
    SI2 Quater Position : (0) SI2 quater message is sent on BCCH Norm

    Message dump (Hex):
    06 1B 34 81 04 75 20 00 65 D2
    00 0F 1A E0 08 B0 00 00 85 20
    00 0B

    MS1
    Time: 10:35:45.42

    Blocked Call
    Block type: No Immediate Assignment

    #66904 Reply
    pix
    Guest

    if there is no sdcch assignment and there is no sdcch congestion, then i would suspect a software problem…

    let’s check qos stats:

    1/ are there SDCCH assigments in the cell?
    2/ what is the main cause of sdcch rejection ?
    3/ what is the mean holding time of a sdcch channel?
    4/ what is the state of your TCH Queuing? (are there MS queued?)

    could you get an immediate assignment with another MS in this cell ?
    and with this TEMS MS in another cell ?

    in your cell, there is the feature multiple CCCH activated. I don’t know if that can cause such problem, but it’s worth investigating.

    Regards
    pix

    #66905 Reply
    Vicky_RF
    Guest

    Hi Pix,
    Thanx,
    The feature multiple CCCH is just activated as there is high ABIS_CCCH load.Another things that you have asked ‘ll let you know.

    #66906 Reply
    pix
    Guest

    ok, can you also check the Abis RSL congestion ?

    #66907 Reply
    UDOH JOSEPH SYLVESTER
    Guest

    MS2
    System Information Type 3

    Time : 13:17:03.68
    Vendor Header
    ARFCN : 80 (E-GSM)
    L2 pseudo length : 18
    Skip indicator : 0
    Protocol discriminator : (6) Radio resources management messages
    Message type : 27
    Cell identity (CI) : 1752 (Hex 0x06D8)
    Location Area Identification
    Mobile country code (MCC) : 621
    Mobile network code (MNC) : 30
    Location area code (LAC) : 40624 (Hex 0x9EB0)
    Control Channel Description
    MSCR : (1) MSC is Release ’99 onwards
    Attach/detach allowed (ATT) : (1) MSs in the cell shall apply IMSI attach and detach procedure
    BS-AG-BLKS-RES : 1
    CCCH-CONF : (0) 1 basic physical channel used for CCCH, not combined with SDCCHs
    CBQ3 : (0) Iu mode not supported
    BS-PA-MFRMS : 2 multiframes period
    T3212 timeout value : (20) 2.0 hours
    Cell options (BCCH)
    Dynamic ARFCN mapping indicator (DN-IND) : (0) Dynamic ARFCN mapping is not used by the PLMN
    Power control indicator (PWRC) : (1) PWRC Set
    DTX indicator : (1) The MSs shall use uplink discontinuous transmission
    RADIO-LINK-TIMEOUT : 4
    Cell selection parameters
    CELL-RESELECT-HYSTERESIS : 14 dB Rxlev hysteresis for LA-reselection
    MS-TXPWR-MAX-CCH : 5
    ADDITIONAL RESELECT PARAM IND (ACS) : (0) System information type 16 and 17 are not broadcast on the BCCH
    HALF RATE SUPPORT (NECI) : (1) New establishment causes are supported
    RXLEV-ACCESS-MIN : 13
    RACH control parameters
    Max retransmission : (0) Maximum 1 retransmission
    Tx-integer : (14) 32 slots used
    Cell bar access : (0) Not barred
    Call reestablishment : (0) Allowed
    Access control
    Emergency Call allowed : (0) All MSs
    Barred classes :
    Rest Octets
    Selection Parameters
    cbq : 0
    Cell reselection offset : (0) 0 dB
    Temporary offset : (0) 0 dB
    Penalty time : (0) 20 s
    System Information 2ter indicator – Not Available
    Early classmark sending control – Explicity accepted
    BCCH scheduling is not sent in SI9
    GPRS indicator
    RA color : 0
    SI13 position : (0) SI13 message is sent on BCCH Norm
    Neither UTRAN nor CDMA2000 classmark change message shall be sent with the Early classmark sending

    Message dump (Hex):
    06 1B 06 D8 26 F1 03 9E B0 C8
    00 14 50 E5 4D 38 00 00 80 00
    00 2B

    #66908 Reply
    UDOH JOSEPH SYLVESTER
    Guest

    At a distance of above 5km, am experiencing no immediate assignment. there are no near by sites to serve only far away site, there by serving cell is having bad rxlevel at the time a call is to be established. what kind of recommendation am i to quote? a new site to be built or increase of BTS power of the serving cell.

    #66909 Reply
    Rizwan
    Guest

    Could some one explain Establishment Cause=17: in Immediate Assignment and how we can control it

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