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Handover failure

Viewing 6 posts - 1 through 6 (of 6 total)
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  • #67085 Reply
    kass33
    Guest

    Hello,

    I had a handover failure but i don’t understand why. Below the log message for layer 3 :

    Quote:
    106702 14:20:00.798 L3 DL RR Handover Command
    BCCH: 49 BSIC: 00(dec) 00(oct)
    Channel Type: TCH/F + FACCH/F and SACCH/F
    TimeSlot: 6 TrainingSeq: 0
    Hopping: Yes, MAIO: 2 HoppingSeq (HSN): 50
    HandoverRef: 38 OrderedPowerLevel: 5
    Target CA List: 34 46 (Variable Bit Map)
    Channel Mode: Speech full rate or half rate version 3 (AMR FR/HR)
    AMR – Multirate speech version 1:
    Codec Count: 1
    Codec Mode 1: Codec 12.20kbps,
    Initial Codec Mode Indicator: Use Default
    Initial Codec Mode: Codec 12.20kbps
    Signal handoff from CHINON_EDF(CHINON_EDF_3) to Unknown(Unknown)

    106703 14:20:00.798 Nemo Handover Attempt

    Context Id: 152
    Number of header parameters: 1,
    Handover/handoff attempt type: GSM handover between cells,
    Current cellular system: GSM,
    Number of current system parameters: 3
    Channel number: 20,
    Timeslot number in use currently: 0
    Band: GSM 900
    Attempted cellular system: GSM,
    Number of attempted system parameters: 3
    Attempted channel number: 49,
    Attempted timeslot: 6,
    Band: GSM 900
    106704 14:20:00.798 Nemo AMR Status
    Cellular system: GSM
    AMR Mode uplink: Codec 4.75kbps
    AMR Mode downlink: N/A
    AMR Last mode command: Codec 4.75kbps
    AMR Last mode request: N/A
    AMR Channel Type:
    106705 14:20:00.798 Nemo AMR Link Quality Estimate

    Cellular system: GSM,
    AMR Link quality estimate (dB): 24.0 dB
    106706 14:20:00.888 Nemo GPS information

    Longitude: 0.107943,
    Latitude: 47.2727,
    Height: 20.000000 m,
    Distance: 214653,
    GPS fix quality: with GPS,
    GPS satellites: 9, Velocity(km/h): 135 kph
    106707 14:20:00.968 Cell measurement (CELLMEAS)

    Cellular System: GSM
    Band BCCH BSIC RxLev RxLevSub C1 C2 C31 C32 HCS HCS Cell ID LAC RAC Srxlev
    Serv: GSM 900 20 2 -85 -84.0 – – – – 0 – 64604 18690 1 –
    Neig: GSM 900 36 11 -89 – – – – – – – – – – –
    Neig: GSM 900 23 21 -90 – – – – – – – – – – –
    Neig: GSM 900 10 35 -92 – – – – – – – – – – –
    Neig: GSM 900 49 0 -94 – – – – – – – – – – –
    Neig: GSM 900 4 0 -96 – – – – – – – – – – –
    Neig: GSM 900 29 23 -97 – – – – – – – – – – –
    Neig: GSM 900 7 5 -98 – – – – – – – – – – –
    Neig: GSM 900 15 – -100 – – – – – – – – – – –
    Neig: GSM 900 12 1 -101 – – – – – – – – – – –
    Neig: GSM 900 11 25 -101 – – – – – – – – – – –
    Neig: GSM 900 1 – -101 – – – – – – – – – – –
    Neig: GSM 900 2 34 -102 – – – – – – – – – – –
    Neig: GSM 900 3 20 -103 – – – – – – – – – – –
    Neig: GSM 900 25 4 -104 – – – – – – – – – – –
    Neig: GSM 900 30 16 -104 – – – – – – – – – – –
    Neig: GSM 900 14 17 -104 – – – – – – – – – – –
    Neig: GSM 900 6 15 -105 – – – – – – – – – – –
    Neig: GSM 900 9 – -106 – – – – – – – – – – –
    Neig: GSM 900 47 – -106 – – – – – – – – – – –
    Neig: GSM 1800 608 – -112 – – – – – – – – – – –
    106708 14:20:00.968 Carrier Per Interference (CI)

    Cellular System: GSM
    Number of timeslot C/I measurement results: 0
    Channel C/I: 15.6 dB
    Number of channels: 3,
    ARFCN C/I (dB) RSSI (dBm)
    5 15.10 -84.90
    8 15.80 -85.60
    16 16.00 -86.70
    106709 14:20:00.968 Nemo AMR Status
    Cellular system: GSM
    AMR Mode uplink: Codec 4.75kbps
    AMR Mode downlink: Codec 4.75kbps
    AMR Last mode command: Codec 4.75kbps
    AMR Last mode request: N/A
    AMR Channel Type:

    106710 14:20:00.968 Nemo AMR Link Quality Estimate

    Cellular system: GSM,
    AMR Link quality estimate (dB): 22.0 dB
    106711 14:20:01.887 Nemo GPS information

    Longitude: 0.107537,
    Latitude: 47.2729,
    Height: 20.000000 m,
    Distance: 214691,
    GPS fix quality: with GPS,
    GPS satellites: 9, Velocity(km/h): 135 kph
    106712 14:20:02.887 Nemo GPS information

    Longitude: 0.107127,
    Latitude: 47.2731,
    Height: 20.000000 m,
    Distance: 214729,
    GPS fix quality: with GPS,
    GPS satellites: 9, Velocity(km/h): 135 kph
    106713 14:20:03.888 Nemo GPS information

    Longitude: 0.106713,
    Latitude: 47.2733,
    Height: 20.000000 m,
    Distance: 214766,
    GPS fix quality: with GPS,
    GPS satellites: 8, Velocity(km/h): 135 kph
    106714 14:20:03.968 Nemo Handover Failure

    Context Id: 152

    Could you please from the log above give me an idea about the handover failure ?

    Thx in advance

    #67086 Reply
    pix
    Guest

    hi,

    it is a full rate TCH using 4.75 kbps AMR codec, which leads me to assume that the C/I is extremely bad. therefore, a ho failure or a call drop should not be a surprise, especially at high speed (looks like you were travelling around 130kph)

    regards
    pix

    #67087 Reply
    Lvin
    Guest

    Dear Pix,
    Is velocity effects on HOF?in which state?as you mentioned :(looks like you were travelling around 130kph).

    #67088 Reply
    pix
    Guest

    lvin,

    when travelling fast, you are exiting the serving cell’s coverage too fast. And during the time the BSC is processing your HO (averaging measurement reports, executing the HO algorithms), the MS may have travelled enough to now be in poor radio conditions.
    In worst case, it can take up to 5 seconds before the MS finally receives the HO CMD. (5s is the max. I would say, typically, 2.5s or 3s)
    5s @ 130kmh = 180m
    that’s enough to get behind a hill, or in a forest… keep in mind the MS was already getting bad coverage, hence the HO detection.

    regards
    pix

    #67089 Reply
    Emna
    Guest

    How can I extract data from this command written in an actix log file ? 🙁

    CELLMEAS,09:54:30.352,,5,0,2,3,10613,-84.0,50001,10588,-86.8,50001,3,17,0,50001,10613,43,-3.5,0,-87.5,,,,,,,,,,121.0,1,50001,10613,135,-13.2,0,-97.2,,,,,,,,,,,1,50001,10588,43,-3.4,0,-90.3,,,,,,,,,,

    I’m unable to find any online documentation explaining the arguments of the command: CELLMEAS.

    #67090 Reply
    nagendra kumar
    Guest

    ression of handover failure

Viewing 6 posts - 1 through 6 (of 6 total)
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