go_na03_e1_1 gsm gprs edge basic principles-49

7/28/2019 Go_na03_e1_1 Gsm Gprs Edge Basic Principles-49

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GSM/GPRS/EDGE Basic Principles

ZTE University



Objective

At the end of this course, you will be able to: Learn GSM development history

Learn and master network structure of GSM system and

functions & principles of different portions

Learn and be familiar with GSM wireless channel and

protocol

Learn and be familiar with main service call process for

GSM



GSM Overview

This chapter mainly introduces some basicinformation for GSM, including GSM development

history, supported service type, specification, and

system features.

GSM Basic Concepts

Services Supported by GSM System

GSM Specification



GSM Overview

This section introduces network structure of GSMsystem and basic functions of various NEs.

GSM Area Division Concepts

GSM composition

Mobile Switching System (MSS)

Base Station Subsystem (BSS)

Operation & Maintenance Subsystem (OMS)

Mobile Station (MS)

GSM System Number



GSM System Composition

IBM

IBM

BSS MSS

MS

MS

PSTN

Other

PLMN

Um

Interfac

e

A

Interf

ace

GSM composition



Mobile Switching System (MSS)

The MSS consists of such entities as the mobileswitching center (MSC), home location register

(HLR), visitor location register (VLR), equipment

identity register (EIR), authentication center (AUC)

and short message center (SMC).



Base Station Subsystem (BSS)

BSS serves as a bridge between the NSS and MS.It performs wireless channel management and

wireless transceiving. The BSS includes the Base

Station Controller (BSC) and Base Transceiver

Station (BTS).



Operation & Maintenance Subsystem (OMS)

The OMS consists of two parts: Operation &Maintenance Center – System (OMC-S) and OMC-

Radio (OMC-R). The OMC-S serves the NSS, while

the OMC-R serves the BSS.



Mobile Station (MS)

The MS consists of mobile terminals and Subscriber Identity Module (SIM) card.



GSM System Number

GSM system number contains: Mobile Subscriber ISDN Number (MSISDN)

International Mobile Subscriber Identity (IMSI)

Mobile Subscriber Roaming Number (MSRN)

Handover Number

Temporary Mobile Subscriber Identification (TMSI)

Location Area Identification (LAI)



GERAN interfaces

This chapter introduces GERAN interfaces, User

plane/control plane protocol stack at PS and CS.

Interfaces

PS-Domain Protocol Stack

CS-Domain Protocol Stack



GSM interfaces

Interfaces



User plane protocol stack at PS domain




Control plane protocol stack at PS

domain




User plane protocol stack at CS domain




Control plane protocol stack at CS

domain




GSM Working Frequency Band

This section introduces GSM radio frame, channel

concept, division & function for different channels,

mapping combination mechanism between

channels.


Structure of GSM Radio Frame

Physical Channel and Logical Channel

System Messages




Currently, the GSM communication system works at

900MHz, extended 900MHz and 1800MHz.

1900MHz band is adopted in some countries.



1 hyper frame = 2048 super frames =2715648 TDMA frame

1 hyper frame = 1326 TDMA frame (6.12s)

(=51 (26 frames) multi-frames or 26 (51 frames) multi-frames

1 (26 frames) multi-frame = 26 TDMA frame (120ms) 1 (51 frames) multi-frame = 51 TDMA frame (3036/13 ms)

TDMA Frame

Hierarchical frame structure in GSM system

Structure of GSM Radio Frame

There are five layers for structure of GSM radio frame, thatis, timeslot, TDMA frame, multiframe, super frame, and

hyper frame.



System Messages

System message falls into 12 types: type1, 2, 2bis,2ter, 3, 4, 5, 5bis, 5ter, 6, 7, 8.



Basic Service and Signaling Process

This section introduces GSM terminal start,position register / update, service call and

handover service implementation and signaling

interaction process.

Mobile subscriber state Location Update

Typical Call and Handover Process

Basic Signaling Process



Mobile subscriber state

The mobile subscriber has three states as follows: MS starts, network does "Attach" marks on it

MS shutdowns, separated from network

MS Busy



Location Update at Same MSC OfficeBSC

（2）

（1）

（3）（4）

MSC/VLR

LAI

1

LAI

2

M

S

M

S

Location update between different MSCs

（5）

（2）

（3）（1）

（4）

HLR

MSC/VLR1

MSC/VLR2

M

S

M

S

Location Update



Call process




Handover process




Location Update Process of MS

RLC

RLSD

DT1：CIPH MODE CM D

RF CH REL ACK

RF CH REL

REL INDUA

DISC

DEACT SACCH

DR ：CH RELCH REL

DT1：Clear COM

DT1：Clear CMD

DT1：CIPH M ODE COMDI：CIPH MODE COM

CIPH MODE COM

CIPH M ODE CMDENCRY CMD

CC

CR ：LOC UPD REQEST IND

UA

SABM

IMM ASSIMM ASS CMD

CH ACT ACK

CH ACT

CH RQDCH REQ

M S BTS BSC M SC

DTAP：LOC UPD ACCEPT




IMSI Detach Process

RF CH REL ACK

RF CH REL

REL INDUA

DISCDEACT SACCH

DR ：CH RELCH REL

CREF

CR ：IM SI DETACHEST IND

UA

SABM

IMM ASSIMM ASS CMD

CH ACT ACK

CH ACT

CH RQDCH REQ

M SBTS BSC M SC


CH REQ

MS BTS BSC MSC



Mobile-Originated Call and CalledParty On-hook Process

RF CH REL ACK

RF CH REL

RLC

RLSD

CH REL

DISC

UARF CH REL

RF CH REL ACK

REL IND

DEACT SACCH

DR ：CH REL

EST IND

ASS COMDT1：ASS COM

DT1:ASS REQ

DT1：CIPH MODE CMD

CH ACT ACK

CH ACT

PHY CONT CONF

UA

SABM

PHY CONT REQ

DR ：ASS CM DASS CMD

DT1：Clear COM

DT1：Clear CM D

DT1：CIPH MODE COMDI：CIPH MODE COM

CIPH MODE COM

CIPH MODE CMDENCRY CMD

CC

CR ：CM SERV REQEST IND

UA

SABM

IMM ASSIMM ASS CMD

CH ACT ACK

CH ACT

CH RQDCH REQ

DTAP:SETUP

DTAP:CALL PROC

DI：ASS COM

DTAP：Alerting

DTAP：Connect

DTAP：Connect ACK

数据流 DTAP：Disconnect

DTAP：Release

DTAP：Release COM

DTAP:CM SERV ACCP


UDT PAG

BSC MSCBTSM S



Mobile-Terminated Call and Calling

Party On-hook Process

UDT：PAGPAG CMDPAG REQ

RF CH REL ACK

RF CH REL

RLC

RLSD

CH REL

DISC

UARF CH REL

RF CH REL ACK

REL IND

DEACT SACCH

DR ：CH REL

EST IND

ASS COMDT1：ASS COM

DT1:ASS REQ

DT1：CIPH MODE CM D

CH ACT ACK

CH ACT

PHY CONT CONF

UA

SABM

PHY CONT REQ

DR ：ASS CMDASS CM D

DT1：Clear COM

DT1：Clear CM D

DT1：CIPH MODE COMDI：CIPH MODE COM

CIPH MODE COM

CIPH MODE CMDENCRY CM D

CC

CR ：PAG RESEST IND

UA

SABM

IMM ASSIMM ASS CMD

CH ACT ACK

CH ACT

CH RQDCH REQ

DTAP:SETUP

DTAP:CALL CONF

DI：ASS COM

DTAP：Alerting

DTAP：Connect

DTAP：Connect ACK

数据流 DTAP：Disconnect

DTAP：Release

DTAP：Release COM




Inter-cell Handover Process

DT1：HO PERF

HO CMD

CH ACT

MEAS REP

RF CH REL ACK

RF CH REL

DI：

HO COM

EST IND

HO DET

CH ACT ACK

MS BTS1 BTS2 BSC MSC

MEAS RES

DR ：HO CMD

HO ACCESS

PHY INFO

SABM

UA

HO COM




key radio enhanced technologies

This section describes basic voice processing for GSM, and several key radio enhanced

technologies.

Voice Processing

Frequency multiplexing Adaptive equalizing

Diversity Receiving

Discontinuous Transmission (DTX)

Power Control

Timing Advance

Frequency Hopping Technology



Voice Processing

Voice Processing in the GSM System



Frequency multiplexing

Frequency multiplexing is the core concept of the cellular

mobile radio system. In a frequency multiplexing system,

users at different geographical locations (different cells)

can use channels of the same frequency at the same time

(see the figure above).



Adaptive equalizing

Equalizer can do equalizing at frequency domainand time domain. GSM uses time domain

equalizing, enabling the better performance in

whole system.



Discontinuous Transmission (DTX)

The DTX mode accomplishes two objectives: Lower the totalinterference level in the air and save the transmitter power.

Speech Frame Transmission in DTX Mode



Power Control

Power control means to control the actual transmitting power (keep it

as low as possible) of MS or BS in radio propagation, so as to reduce

the power consumption of MS/BS and the interference of the entire

GSM network.

Power Control Process



Timing Advance

In the GSM, the MS requires three intervals between timeslots when

receiving or transmitting signals. See the figure below.

Uplink and Downlink Offset of TCH



Frequency Hopping Technology

Frequency hopping (FH) refers to hopping of the carrier frequency

within a wide frequency band according to a certain sequence.

Basic Structure of FH

ti d ib l ti f GSM



section describes evolution of GSM

technologies

This section describes evolution of GSMtechnologies: basic concept, network structure,

radio channel, and basic application of GPRS and

EDGE.

Definition and Feature Inheritance and Evolution

GPRS Radio Channel

Radio Link and Media Access Control Flow

Terminal and Application



Definition and Feature

Enhanced Data Rate for GSM Evolution (EDGE) is a kind

of technology for transition of GSM to 3G.

The EDGE has the following features:

EDGE neither changes GSM or GPRS network structure nor

introduces new network element, but only upgrades the BSS.

EDGE does not change the GSM channel structure, multiframestructure and coding structure.

EDGE supports two data transmission modes: packet service (non-

real time service) and circuit switching service (real time service).

EDGE adopts octal 8PSK modulation technology, supports 303%

of GMSK payload, and provides higher bit rate and spectral

efficiency.

Compared with GPRS, EDGE adopts new coding mode.



GPRS Radio Channel

This section introduces GPRS physical channel,GPRS logic channel, mapping of logical channel

combination in the physical channel, and GPRS

channel coding.



Radio Link and Media Access Control Flow

This section introduces paging flow, TBF setupflow, GPRS suspend/resume flow, and TBF

release flow.



Terminal and Application

The GPRS MSs fall into three categories: Type A,B, and C.

go_na03_e1_1 gsm gprs edge basic principles-49

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