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    For Inter-RAT Handover

    Uploaded by

    Wilfred Mangwaira
    The document discusses inter-RAT handover between WCDMA and GSM/GPRS networks. It describes the typical handover process and different handover strategies used at different stages of 3G network construction, including coverage handover, load handover, and service handover. It also provides recommended values for key reselection and handover parameters when handing over between 3G and 2G networks.

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    For Inter-RAT Handover

    Uploaded by

    Wilfred Mangwaira
    54 views3 pages
    The document discusses inter-RAT handover between WCDMA and GSM/GPRS networks. It describes the typical handover process and different handover strategies used at different stages of 3G network construction, including coverage handover, load handover, and service handover. It also provides recommended values for key reselection and handover parameters when handing over between 3G and 2G networks.

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    The document discusses inter-RAT handover between WCDMA and GSM/GPRS networks. It describes the typical handover process and different handover strategies used at different stages of 3G network construction, including coverage handover, load handover, and service handover. It also provides recommended values for key reselection and handover parameters when handing over between 3G and 2G networks.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    54 views3 pages

    For Inter-RAT Handover

    Uploaded by

    Wilfred Mangwaira
    The document discusses inter-RAT handover between WCDMA and GSM/GPRS networks. It describes the typical handover process and different handover strategies used at different stages of 3G network construction, including coverage handover, load handover, and service handover. It also provides recommended values for key reselection and handover parameters when handing over between 3G and 2G networks.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 3

    Inter-RAT Handover

    Inter-RAT Handover Scenario


    The handover between WCDMA and GSM/GPRS occurs in the Cell_DCH state of the
    connected mode, and an effective handover between WCDMA and GSM/GPRS can ensure
    that the users can use the current service continuously.
    The typical process of inter-RAT handover: once UE is in the connection state (the
    CELL_DCH state in WCDMA), it performs the “measurement” instruction from network, and
    reports the result to the network by period or event, the network judges the UE signal quality
    based on the reported result, and determines whether the cell phone to handover.

    Inter-RAT Handover Strategies for Different Stages


    1. Coverage Handover: In the initial stage of 3G construction, given the network condition of
    continuous GSM coverage and limited 3G coverage, it adopts the handover based on
    coverage for the places with poor coverage.
    2. Load Handover: In the middle and late stages of 3G construction, 3G network extends
    very fast, 3G and 2G networks overlap basically, 2G network needs to share load for 3G
    network, it adopts load handover that is based on the load of 3G network.
    3. Service Handover: In the middle and late stages of 3G construction, the RNC of 3G
    network receives RAB assignment message, the services should be handed over to 2G
    according to the requirement from core network, thus 3G users are handed over to 2G network,
    and it is called service handover.

    Current Inter-RAT Handover Strategy


    At present, given the network GSM coverage and limited 3G coverage, it adopts the
    handover based on coverage for the places with poor coverage. The specific handover
    strategy is as follows: it is a one-way handover from 3G to 2G for CS, and it is a two-way
    handover from 3G to 2G for PS

    Recommended Values of Key Reselection Parameters


    1.3G->2G Reselection
    Recommended Values of Key 3G ->2G Reselection Parameters:

    Recommended
    Parameter Description
    Value

    Qqualmin Lowest access quality of 3G cell signal -16dB

    QRxLevMin Lowest access strength of 3G cell signal -110dBm

    inter-RAT measurement trigger threshold for cell


    SSearchRat 4dB
    reselection
    QHyst1S Reselection delay of serving cell 1 10 dB

    Qoffset1SNSib11 Quality offset 1 of serving and neighbor cells in SIB11 0 dB

    Qoffset1SNSib12 Quality offset 2 of serving and neighbor cells in SIB12 0 dB

    Treselection Time duration of cell reselection timer 1s


    2. 2G->3G Reselection
    Key 2G ->3G Reselection Parameters:
    FDD_Qoffset FDD Reselection Offset 0 (–∝)

    FDD_Qmin Minimum value of Ec/No of UTRAN reselection cell 7(-12 dB)

    Threshold for UE to start UTRAN cell reselection


    Qsearch_I 7 (always)
    measurement
    Note:It shows -∝ when the FDD_Qoffset is set to 0. The reason for setting it to be 0 is
    that UE does not need to consider the strength comparison between 2G and 3G. If it
    requires the UE to select 3G as far as possible in the field, this parameter can be set to 0

    Recommended Values of Key Inter-RAT Handover Parameters


    3G->2G Parameters List:
    Recommended
    Parameter Definition Class Unit
    Value
    CPICH Ec/Io 2D CS dB -10
    2D quality threshold
    Threshold PS dB -13
    CPICH RSCP 2D CS dBm -90
    2D strength threshold
    Threshold PS dBm -105
    Delay range for 2D
    Hysteresis2D CS/PS dB 4
    judgment
    TimeToTrigger2D Timer to trigger Event 2D CS/PS ms 640
    CPICH Ec/Io 2F CS dB -5
    2F quality threshold
    Threshold PS dB -5
    CPICH RSCP 2F CS dBm -85
    2F strength threshold
    Threshold PS dBm -100
    Delay range for 2D
    Hysteresis2F CS/PS dB 4
    judgment
    TimeToTrigger2F Timer to trigger Event 2F CS/PS ms 640
    CPICH Ec/Io 3A 3A quality threshold CS dB -6
    Threshold 3A quality threshold PS dB -6
    CPICH RSCP 3A CS dBm -90
    3A strength threshold
    Threshold PS dBm -102
    Hysteresis3A 3A delay window CS/PS dB 4
    TimeToTrigger3A Timer to trigger Event 3A CS/PS ms 100

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