gsm based cellular_rf level 1

8/3/2019 GSM Based Cellular_RF Level 1

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RF Engineering

Level-1

Course Duration : 4 days


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Introduction to GSM


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1.1 : Introduction to GSM


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1.1.1: GSM Channelization


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1.1.1: GSM Channelization


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Logical Channel Type

Broadcast control channel

(BCCH) Control channelCommon control channel

(CCCH)

Voice channel

(TCH)

FCH SCH BCCH

(system information)

TCH/FAGCH RACH SDCCH FACCH

SACCH

TCH/H

TCH/9.6F

TCH/ 4.8F, H

TCH/ 2.4F, H

PCH

Common channel

(CCH)

Dedicated channel

(DCH)

Logical channel

GSM900 and DCS1800 have the same logical channel category


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LogicalChannel

Direction BTS MS

FCH

Down Link , Point toMultipoint

Transmit a Carrier frequency Identifies BCCH carrier by the carrierfrequency and synchronizes with thefrequency.

SCH Down Link , Point to

Multipoint

Transmit TDMA frame &

Base station BSIC.

Synchronizes with the frame structure

with a particular cell & carriesinformation about TDMA frame numberand Base Station Identity Code (BSIC)of the BTS.

BCCH Down Link , Point toMultipoint

Broadcast some generalinformation like LAI, max out

put power allowed in a cell &the identity of BCCH carrierfor neighboring cell.

Receives LAI and will be signed to thenetwork as part of the location

updating procedure. MS sets the output power according to the strength ofBCCH.

Broadcast Channel


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Logical Channel Direction BTS MS

PCH

Down Link , Point to point. Transmit paging messagecontains the identity number ofthe mobile subscribers that the

network wishes to connect.

After certain interval MS listen tothe paging message . If it

identifies its own subscriber it will

respond.

RACH Up Link , Point toMultipoint

Receive request from MS forsignaling channel.

Answer paging message on theRACH by requesting a signaling

channel.

AGCH Down Link , Point to point Assign a signaling channel (SDCCH ) for the MS.

Receives Signaling channelassignment ( SDCCH )

Common Control Channel


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Logical Channel Direction BTS MS

SDCCHUp & Down , Point to

point.The BTS switches to the

assigned SDCCH. The callsetup procedure is

performed in idle mode. TheBSC assigns TCH.

The MS switches to the assigned SDCCH.Call setup is performed. The MS receivesTCH assignment information. ( Carrier &

Time slot )

SACCH Up & Down , Point topoint

Instructs the MS thetransmitting power to useand gives instructions on

timing advance.

Sends averaged measurements on itsBTS ( Signal strength & Quality ) and

neighboring BTSs ( Signal strength ).TheMS continues to use SACCH for this

purpose during a call.

FACCH Up & Down , Point to

point

Transmit handover

information

Transmit handover request.

Dedicated Control Channel


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1 1 2 GSM N t k El t & F ti liti


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1.1.2: GSM Network Elements & Functionalities


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Service Area


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Page 61

PLMN service area

......

System area

PLMN service areaMSC service area...

Location area...

Base station area...

Radio cell

...... ......

MSC service area...

Location area...

Base station area...

Radio cell

PLMN service area

Service Area


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MSC/VLR Number


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The format is CC+NDC+LSPCCCountry Code.For example: The CC of China is "86".

NDCNational Destination Code.For example: The NDC of China Mobile is 139138137136135.LSP(locally significant part): is defined by Telecom operator.For example: 86-139-00311

CC NDC LSP

MSC/VLR number

MSC/VLR Number

HLR Number


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The format isCC+NDC+H0 H1 H2 H3 0000.CCCountry Code.For example: The CC of China is "86".

NDCNational Destination Code.For example: The NDC of China Mobile is

139138137136135.H0H1H2H3 is defined by Telecom operator.For example: 86-139-0666-0000.

HLR Number

LAI


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Location Area Identification

The LAI is the international code for a location area.

MCC MNC LAC

MCCMobile Country CodeIt consists of 3 digits .For example: The MCC of China is "460"

MNCMobile Network CodeIt consists of 2 digits .For example: The MNC of China Mobile is "00"

LAC Location Area CodeIt is a two bytes BCD code (hex).The value 0000 and FFFF is invalid.

For example: 460-00-0011

CGI


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CGI: Cell Global Identification

The CGI is a unique international identificationfor a cell

The format is CGI = LAI+CI= (MNC+MCC+LAC)+CILAI: Location Area Identification

CICell Identity. This code uses two bytesBCD code (hex) to identify the radio cells

within an LAI.For example : 460-00-0011-0001

BSIC


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NCC BCC

BSIC

BSICBase Station Identification Color Code)

NCC: PLMN network color code. It comprises 3bit. It allows various neighboring PLMNs to bedistinguished.BCC: BTS color code. It comprises 3 bit. It allowsdistinctionbetween different radio frequency channelsusing the same frequency in neighboring cells.

BSIC=NCC+BCC

Additional Example


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p

MSISDN


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CC NDC SN

National (significant)Mobile number

Mobile station internationalISDN number

CC Country Code. For example: The CC of China is "86".NDCNational Destination Code. For example: The NDC of ChinaTelecom is 139, 138, 137, 136, 135.

SN Subscriber Number. Format:H0 H1 H2 H3 ABCDExample: 86-139-0666-1234

IMSI


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Not more than 15 digits

3 digits 2 digits

IMSI

MCC MNC MSIN

NMSI

MCCMobile Country CodeIt consists of 3 digits .For example: The MCC of China is "460"

MNCMobile Network CodeIt consists of 2 digits .For example: The MNC of China Telecom is "00"

MSINMobile Subscriber Identification Number. H1H2H3 S ABCDEFFor example: 666-9777001

NMSINational Mobile Subscriber IdentificationMNC and MSIN form ittogether.For Example of IMSI : 460-00-666-9777001

TMSI


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TMSI: Temporary Mobile Subscriber Identification)

S

The TMSI is assigned only after successful subscriberauthentication.

The VLR controls the allocation of new TMSI numbers andnotifies them to the HLR.

TMSI is used to ensure that the identity of the mobilesubscriber on the air interface is kept secret.

The TMSI consists of 4 bytes( 8 HEX numbers) anddetermined by the telecom operator.

IMEI


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TAC FAC SNR SP

IMEI

IMEI: International Mobile Station Equipment Identification

TAC: Type approval code. It is administered by the type approval center.FAC: Final assembly code.It is administered by the manufacturer.SNRSerial number. It is issued by the manufacturer of the MS.SPNot used.

MSRN/HON


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MSRN: Mobile Subscriber Roaming Number

HON: Hand-over Number

/

The MSRN is used to route the call to the MSC which MS is

currently located. The HON is used by the MSC-A to set up a connection to the

MSC-B during handover process

Usually, MSRN and HON share the same numbering plan.

The format is CC+NDC+individual number. CC and NDC is

the same as that of MSISDN. The individual number is takenfrom a pool of numbers specially reserved for MSRN.


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gsm based cellular_rf level 1

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