Tems Final

Date post:04-Jun-2018
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    RF Optimization (Drive Test)

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    Objective (brief)

    Understanding Optimization

    Overview H/w used in TEMS Using TEMS

    Question in Interview

    Review

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    Objective Understanding meaning of RF Optimization

    H/w & S/W used in TEMS

    Understand GSM protocol

    Understand LAP-Dm

    Using TEMS Drop Call Analysis

    Handover Analysis

    Troubleshooting with TEMS

    Question in Interview

    Review

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    Understanding Optimization

    Optimization is the process of improving operationof the network to better utilise available Infra.

    to provide customers of the service the best possible

    quality of service.

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    H/w & S/W used in TEMS

    TEMS Dongle

    TEMS software

    Laptop GPS

    Mobile

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    TMES Dongle

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    GPS

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    Latitude

    Longitude

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    Latitude parallel to equator

    Longitude parallel to meridian

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    lat=19.187055N

    lon=72.970878E

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    TEMS

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    Understand GSM protocol

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    Understand GSM protocol

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    Layer 3 Messages

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    Layer 3 Message System Information Type 1

    System Information Type 2

    System Information Type 3

    System Information Type 4

    System Information Type 5

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    SYSTEM INFORMATION TYPE 1

    sent on the BCCH

    Information of control of the RACH

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    SYSTEM INFORMATION TYPE 2 sent on the BCCH

    BCCH allocation in the neighbour cells.

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    SYSTEM INFORMATION TYPE 3

    The location area identification,

    The cell identity

    various other information about cell

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    System information type 5 sent on the SACCH by the network

    Any change in the neighbour cells

    description

    Mobile station must analyse all

    correctly received messages.

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    PAGING REQUEST TYPE 1

    sent on the CCCH by the network

    Up to two mobile stations

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    PAGING REQUEST TYPE 2

    Three mobile stations

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    Understanding LAP-Dm

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    Layer 2 Messages

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    Using TEMS

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    Serving Cell

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    Cell ID 16bit identifier

    CGI= Cell ID + MCC + MNC +LAC

    LAC < 65535

    (Cell Global Identity).

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    Base Station Identity Code

    Important in border areas

    3-bit network color code (NCC) assigned by regulatory authority

    3-bit base-station color code (BCC) assigned by the network operator

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    Serving and Nighbouring cell

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    RxLEV

    Measured in dBm units

    Rxlev (-110 to 47) dbm

    RxLEV (0 to 63)GSM unit

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    Cell selection For example,

    If the minimum allowed level is -100dBm

    Average received signal level is - 80dBm

    The terminal evaluates C1 as +20.

    The terminal always selects for attach the cell

    with highest C1.

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    Mobile allocation index offset(MAIO)

    Time delay separating traffic channels.

    Hopping sequence number (HSN).

    The hopping pattern must be known both by thereceiver and the transmitter.

    The smallest amount of interference on a site

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    Frame Erasure Rate

    Speech Quality Index

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    Troubleshooting With TEMS

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    Troubleshooting With

    TEMS

    Call drop

    Hand Over

    Congestion

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    Troubleshooting Call Drop

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    Check Interference Internal

    Co-channel Interference Change Frequency

    MS power

    Turn on Frequency Hopping Put more TRU

    External wireless alarm system

    Check Antenna Direction & Position

    Low Signal Strength

    Timing Advance

    Ping-pong Handover Call dropped on the TCH.

    Call dropped on the SDCCH

    DRAGON site

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    Excessive Timing advanceTA value is higher than TALIM

    Reducing the coverage If cell is really covering far away from BTS

    Tilting the antennas,

    Reducing antenna height

    Changing antenna

    Reducing output power

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    Excessive Timing advanceThe maximum BTS radius of 35 Km

    is divided into 64 TA steps

    i.e. 1 TA = 547 Meter OR 550 Meter

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    Excessive Timing advance

    Check the BTS error log

    Run commands: RXELP & RXMFP

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    Low signal strength Received signal level,

    Measured in dBm units

    Rxlev (-110 to

    47) dbm RxLEV (0 to 63)GSM unit.

    Either BCCH channel in idle mode

    both BCCH and TCH

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    Handover Analysis

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    Handover Analysis No or few handover attempts:

    whether the target cell is congested, ifcongested, solves the congestion problem.

    Check if BTS is defined but might not be inservice.

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    Handover Analysis

    (BTS Log)

    PDF

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    Question in Interview 1

    How to connect gps and mobile?

    GPS components used?

    whic mobiles are been used?

    Laptop which pin is used to connect the gps?what parameters are used to measure call drop?

    what parameters are used to measure handoff?

    what u mean by RX-LEVEL?

    what u mean by RX-QUAL?what does the term power budget mean?

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    Assignment for Student

    How can you calculate the coverage and capacity of a GSM

    network?

    How do you make a link budget? Which parameters are included in System Information? How can you increase coverage and capacity? How does the choice of antennas affect network performance?

    What are C/I, C/A ? How can repeaters improve the network performance?

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    Thank you

    Design by Mahesh Tawade

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