03 go_na07_e1_1 gsm signaling system-48

8/20/2019 03 GO_NA07_E1_1 GSM Signaling System-48

http://slidepdf.com/reader/full/03-gona07e11-gsm-signaling-system-48 1/48

GSM Signaling System



Objectives

At the end of this course, you will be able to: Know GSM system signaling model

State various types of GSM protocol messages

nderstand GSM system basic signaling procedure



!ontent

GSM System Signaling Model GSM protocol message

"asic Signaling #rocedure



GSM $nterface

SGSN

AbisUm

BTS

BSC

TRAU

GGSN

MSC/VLR/GMSC

NSMU FSMU

Ater A

OMC

Qx

HLR/AUC

EIR SMC

PSTN / PLMN /

PSPDN / ISDN

BTS

BTS

BTS

Gb



GSM System Signaling Model

GSM system signaling model adopts the lowest threelayer of OS$ seven layer protocol model, from low to

high:

Application layer

%in& layer'(etwor& layer

#hysical layer



#hysical %ayer

)he physical layer provides error protectiontransmission* $t defines the electric parameters of

transmission*

$n +)-GSM digital mobile communication

systems, )he physical layer of m interface

between MS and ")S is .adio lin&* Abis interface

physical layer adopts /0-ohm coa1ial cable or

234-ohm symmetrical twisted pair whose rate is3Mbit's*



5ata %in& %ayer

)he data lin& layer major functions: frametransmission、 error-free transmission and reali6e

end-to-end bits transfer between two connective

entities* Open、 maintenance and close the

connection of two connective entities* )he lin& layer protocol used by the GSM system at

the radio interface is the %A#5m protocol 75m

channel lin& access procedure8* )he data lin&layer of Abis interface between ")S and "S! is

%A#5 75 channel lin& access procedure8*



Application %ayer

Application Layer

CM MM RR

CC SS SMS



Application %ayer

.adio .esources 7..8 management handles theestablishment, maintenance and release of physical

channels* $ts major functions are performed by "S!* #art

of functions are performed by ")S*

Mobility Management 7MM8 deals with the mobile station9sregister and the identify of the mobile subscriber, )he

function are performed by MS!*

)he !M %ayer is composed of three functional entities:

!all !ontrol 7!!8, deals with the functions to establish、

maintenance and release the call； Short Message

Service support 7SMS8 and Supplementary Service

support 7SS8*



Mobile

Switching

!entre

7MS!8

8 8 8 8

8 8

"ase

)ransceiver

Station

7")S8

"ase

Station

!ontroller

7"S!8

uipment

$5

.egister

7$.8

;isitor

%ocation

.egister

7;%.8

<ome

%ocation

.egister

7<%.8

Authenti-

cation

!entre

7A!8

Mobile

Switching

!entre

7MS!8

#ublic Switched

)elephone (etwor&

7#S)(8

MA#')!A# = $S#')#

)o other ;%.

$S#')#

5)A# = "SSMA#

MA#')!A#

MA#')!A# MA#')!A#

")SM

A-bis interfaceA interface

GSM protocol



DTAP

5)A# 5irect )ransfer Application #art"SSMA# "SS Management Application #art!M !all ManagementMM Mobile Management.. .adio .esource Management

S!!# Signalling !onnection !ontrol #artMA# Mobile Application #art)!A# )ransaction !apability Application #art$S# $S5( ser #artM)# Message )ransfer #art

CM

MM

RR

Sig !a"er #

La"er $ %air&

Sig !a"er #

Sig !a"er $

MTP

SCCP

BSSMAPRR

%CM'MM&

MS BSC

MTP MTP

SCCP SCCP

CM

MM

BSSMAP TCAP

MAP

(

S

U

P

MSC

Sig !a"er #

La"er $ %air&

BTS

%CM&

%MM&

%RR&

%CM&

%MM&

%RR&

%CM&

%MM&

%LAPDm& %LAPDm& %LAPD&Sig !a"er #

Sig !a"er $

%LAPD&

BTSMBTSMRR)

")SM ")S Management

Um (nterface Abis (nterface A (nterface (nter-MSC

(nterface

GSM #rotocol Architecture



!ontent


"asic Signaling #rocedure



m interface protocol stac&

CM

MM

RR

LAPDm

Layer1 Layer1

LAPDm

RR

MS BTS

Um interface



%A#5m frame format

)he address field contains the service

access point identifier 7SA#$8* SA#$ > 4 represents the signaling lin&

SA#$ > ? represents the short message lin&

$n the control field, ( 7S8 represents the sending serial number

( 7.8 represents the receiving serial number

Address Control Information

SAPI N(S) N(R)



Operation mode

Ac&nowledged mode: .euires the confirmationfrom the receiver* )his mode provides a whole set

of control mechanism for error recovering and flow

control, the establishment mechanism and release

mechanism for multi-frame operations* nac&nowledged mode: )he receiver is not

reuired to send a confirmation upon reception of

a $ frame* )his operation mode does not provide

flow control or error recovering mechanism*



.. messages

)ype Message

!hannel establishment message $mmediate assignment

$mmediate assignment reject

!iphering message !iphering mode command

!iphering mode complete

<andover message

<andover command

<andover complete

<andover failure

<andover access

!hannel release message !hannel release#aging message #aging reuest

#aging response

System info System info:2～ @



MM messages

)ype Message

.egistration messages$MS$ detach indication

%ocation updating accept

%ocation updating reject

%ocation updating reuest

Security messages

Authentication reject

Authentication reuest

Authentication response

$dentity reuest

$dentity response

)MS$ reallocation command

)MS$ reallocation complete

!onnection-management messages

!M service accept

!M service reject

!M service reuest



!! messages

)ype Message

!all establishment messages

Alerting

!all confirmed

!all proceeding

!onnect

!all clearing messages

5isconnect

.elease

.elease complete

Miscellaneous messages!ongestion control notify

Start 5)M

Stop 5)M



Abis $nterface #rotocol stac&



%A#5 #rotocol

SA#$ > 4 represents the signaling lin&,

SA#$ > B3 represents the OCM lin&, and

SA#$ > B? represents the management lin& of the %ap5 layer*



A interface protocol stac&

BSC

MTP3

MTP2

Layer1

MSC

A interface

Layer1

MTP2

MTP3

RR

SCCP SCCP

BSSAP BSSAP

MM

CM



.elationship between S!!# and OS$ model

MTP-1

MTP-2

MTP-3

SCCP

ISP

TCAP

INAP OMAP MAP BSSAP ISUP TUP

HLR VLR

Layer1

Layer2

Layer3

4 ～ 6

Layer 7



"SSA#

MTP

SCCP

Distribution

BSSMAP DTAP

BSSAP

RR

MM

CC

MTP

SCCP

Distribution

BSSMAP DTAP

BSSAP

L1

LAPDm

RR

CC

MM

RR

LAPDm

L1

MSCBSS

MS

DTAP

BSSMAP ： DTAP ：



S!!# message

!. !onnection reuest !! !onnection confirm

!. !onnection refused

.%S5 .eleased .%! .elease complete

5)2 5ata form 2

5) nit data

5)S nit data service



"SSMA# Message -2

Assignment messages 7setup of traffic channels8 Assignment reuest Assignment complete Assignment failure

<andover messages <andover reuest 7to "S!: reuest for handover to that "S!8 <andover reuired 7to MS!: inter "S!'MS! handover reuired8

<andover reuest ac&* 7to MS!: ac&nowledge of handover reuest8 <andover command 7to "S!: contains new radio channel'")S for the

MS8 <andover complete 7to MS!: commanded handover successful8 <andover failure 7to MS!: commanded handover unsuccessful8 <andover performed 7to MS!: "S! has performed internal handover8 <andover candidate enuiry 7to "S!: MS! reuests list of MS that could be

handed over to another cell8 <andover candidate response 7to MS!: answer to handover candidate enuiry8 <andover reuired reject 7to "S!: reuired handover unsuccessful8 <andover detect 7to MS!: commanded handover successful8



"SSMA# Message -3

.elease messages !lear command 7release of traffic channel8 !lear complete !lear reuest SA#$ DnE clear command 7control of layer 3 SA#$ DnE on the radio interface8 SA#$ DnE clear complete SA#$ DnE reject

General messages .eset 7initialisation of "SS or MS! due to failure8 .eset ac&nowledge Overload 7processor or !!!< overload8 )race invocation 7start production of trace record .eset circuit 7initialisation of single circuit due to failure8

)errestrial resource messages "loc& 7management of circuits'time slots between MS! and ")S8 "loc&ing ac&nowledge nbloc& nbloc&ing ac&nowledge



"SSMA# Message -3

.adio resource messages .esource reuest 7available radio channels in

"SS cells8

.esource indication

#aging 7paging of MS8 !ipher mode command 7start encryption8

!lassmar& update 7change of MS power

class8

!ipher mode complete

Fueuing indication 7indicates delay in

assignment of tch8



!ontent


Basic Signaling Procedure



Mobile Originating !all stablishment #rocedure -2



Mobile Originating !all stablishment #rocedure -3



Mobile Originating !all stablishment #rocedure -?



Mobile )erminating !all stablishment #rocedure -2



Mobile )erminating !all stablishment #rocedure -3



Mobile )erminating !all stablishment #rocedure -?



%ocation pdate #rocedure -2



%ocation pdate #rocedure -3



$ntra !ell <andover #rocedure



$ntra "S! <andover #rocedure



$nter "S! <andover #rocedure



!all .e-establishment #rocedure



5irected .etry #rocedure



Short Message #rocedure On S5!!< hen MS $s

!alling -2




!alling -3




!alled -2




!alled -3



Short Message #rocedure On SA!!< hen

MS $s !alling



Short Message #rocedure On SA!!< hen

MS $s !alled

03 go_na07_e1_1 gsm signaling system-48

Documents