Oma000001 gsm fundamentals issue3.3

Wireless Curriculum Development SectionWireless Curriculum Development SectionWireless Curriculum Development SectionWireless Curriculum Development Section

ISSUEISSUE 3.33.3

OMA000001OMA000001GSM FundamentalsGSM Fundamentals

OMA000001OMA000001GSM FundamentalsGSM Fundamentals

2

Security Level: InternalConfidential Information of Huawei. No Spreading without Permission.

Contents Contents haoxiuyan:haoxiuyan:

haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan:

haoxiuyan:haoxiuyan:

Basic Concepts of Cellular Mobile SystemBasic Concepts of Cellular Mobile System

GSM Network Components

Terrestrial Interface

Service Area and Number Planning

Channels on The Air Interface

Radio Technologies

The Future Development

3


ObjectivesObjectiveshaoxiuyan:haoxiuyan:



Name the frequency spectrum used in GSM

Name the concept of frequency reused.

Name the two different cell types and understand why and when each would be used.

Name the frequency spectrum used in GSM

Name the concept of frequency reused.

Name the two different cell types and understand why and when each would be used.

On completion of this section the student will be able to:

4


GSM 900GSM 900

Duplex Separation: 45MHz

Channel Bandwidth: 200KHz

EGSM

880 890 915 925 935 960MHz

GSM EGSM GSM

The Frequency SpectrumThe Frequency Spectrum

5


Duplex Separation: 95MHz

Channel Bandwidth: 200KHz

Base Station Receive

1710 1785 1805 1880MHz

Base Station Transmit

DCS 1800DCS 1800

The Frequency SpectrumThe Frequency Spectrum

6


Frequency Re-UseFrequency Re-Use

Because frequency resource of mobile system is very limited,

The different Subscribers must use the same frequency in different place.

Of course, the quality of communication must be ensured.

What is Frequency Re-Use?What is Frequency Re-Use?

7



How can we reuse frequency?How can we reuse frequency?

7(Site)X 1(Cell) Re-use 2

1

2

3

4

5

6

7

8



4(Site)X 3(Cell)

Re-use

5

1

9 6

10

2

7

3

115

9

1

10

212

8

4

11

7

3

9

5

1

6

9


CELLCELL

Omni

1

120degree

1

23

Omni-Directional CellsOmni-Directional Cells

120 Degree Sectors120 Degree Sectors

10





Basic Concepts of Cellular Mobile System

GSM Network ComponentsGSM Network Components




Radio Technologies


11


On completion of this section you will be able to:

Draw the structure of GSM

Identify the functions of each component

ObjectivesObjectives

12


AUCAUC

MEME SIMSIM

OMCOMC

HLRHLR

MSC/VLRMSC/VLR

BTSBTS BSCBSC

PSTN

OSS

MS

NSS

BSS

EIREIR

GSM Network ComponentsGSM Network Components

13


Mobile Station—MSMobile Station—MS

International Mobile Equipment Identity (IMEI)

– Mobile Equipment

MS=ME+SIMMS=ME+SIM

International Mobile Subscriber Identity (IMSI)

– Subscriber Identity Module

14


Subscriber Identity Module – SIMSubscriber Identity Module – SIM


Temporary Mobile Subscriber Identity (TMSI)

Location Area Identity (LAI) Subscriber Authentication Key

(Ki) Mobile Station International

Standard Data Network (MSISDN),

it is optional.


Temporary Mobile Subscriber Identity (TMSI)

Location Area Identity (LAI) Subscriber Authentication Key

(Ki) Mobile Station International

Standard Data Network (MSISDN),

it is optional.

GS

M

15


The Base Station

Controller – BSC The Base Transceiver

Station – BTS The Trans-coder – TC

and Sub multiplexer

(SM)

The Base Station

Controller – BSC The Base Transceiver

Station – BTS The Trans-coder – TC

and Sub multiplexer

(SM)

BTSBTS

BSCBSC

TC/SMTC/SMBSS

MSC

Base Station Subsystem – BSSBase Station Subsystem – BSS

16


Mobile Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Inter-Working Function – IWFEcho Cancellor – EC

Mobile Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Inter-Working Function – IWFEcho Cancellor – EC

AUCAUCHLRHLR

MSC/VLRMSC/VLR

PSTN

NSS

EIREIROMC

BSS

ECEC

IWFIWF

The Network Switching SystemThe Network Switching System

17


Mobile Service Switching Center – MSC Mobile Service Switching Center – MSC

Call Processing

Operations and Maintenance

Support

Inter-network & Inter-working

Billing

Call Processing

Operations and Maintenance

Support

Inter-network & Inter-working

Billing

18


Home Location Register – HLR Home Location Register – HLR

Subscriber ID (IMSI and MSISDN)

Current subscriber VLR (current location)

Supplementary service information

Subscriber status (registered/deregistered)

Authentication key and AuC functionality

Subscriber ID (IMSI and MSISDN)

Current subscriber VLR (current location)

Supplementary service information

Subscriber status (registered/deregistered)

Authentication key and AuC functionality

19


Visitor Location Register – VLR Visitor Location Register – VLR

Mobile Status(IMSI detached/ attached)

Location Area Identity(LAI)

Temporary Mobile Subscriber Identity(TMSI)

Mobile Station Roaming Number(MSRN)

Mobile Status(IMSI detached/ attached)

Location Area Identity(LAI)

Temporary Mobile Subscriber Identity(TMSI)

Mobile Station Roaming Number(MSRN)

20


IMEIIs Checked against White List

IMEIIs Checked against Black/Grey List

If NOT found, checked against Grey/Black List

If NOT found, checked against White List indications

If found, returns a Black or Grey List indicator

•White List•Black List•Grey List

Equipment Identity Register – EIR Equipment Identity Register – EIR

21


• Rate Conversion• Protocol Adaptation

PSTN

MSCMSC

ECEC IWF

Inter-Working Function – IWFInter-Working Function – IWF

22


Echo takes place by GSM system delay caused by call processing,speech encoding and decoding etc.An Echo Canceller is used on the PSTN side of the MSC for all voice circuits

2-wire4-wire

2- wire

Hybrid Hybrid

Generation of Echo at 2-wire to 4-wire Interface

Echo Canceller － ECEcho Canceller － EC

23


OSS(NMC)

OMCOMC

OMC

Region2

Region 1

Region 3

Operation and Maintenance Sub SystemOperation and Maintenance Sub System

24


Operation and Maintenance Center – OMC Operation and Maintenance Center – OMC

OMC – R: OMC assigned specifically to the Base Station Subsystem

OMC – S: OMC assigned specifically to the Network Switching Subsystem

25


OMC Functional ArchitectureOMC Functional Architecture

OS

MMI

DB

Event/AlarmManagement

SecurityManagement

ConfigurationManagement

Performance Management

Fault Management

26







Terrestrial InterfaceTerrestrial Interface



Radio Technologies


27



Identify the protocols used on the terrestrial interfaces between the GSM system entities


28


HLR

VLR

MSC

EIR

AUC

EC IWF

TC

VLR

MSC

IWF EC

BTS BSCMS

B

H

F

G

A

E

C

D

Um Abis

GSM InterfaceGSM Interface

29


CM

MM

RR

LAPDm

SigL1

L3

L2

L1

MS

RR BTSM

LAPDm

SigL1

LAPD

SigL1

LAPD

SigL1

BTSM

RR

SCCP

MTP

BSSMAP

CM

MM

BSSMAP

SCCP

MTP

MSCBSCBTS

Um½Ó¿Ú A½Ó¿ÚAbis½Ó¿Ú

GSM ProtocolGSM Protocol

30


HLR

MSC/VLR

EIRAUC

EC

OMC

MSC/VLR

TC

IWF

EC

BSC PSTN

BTSBTS BTS

SigL1: 2MBps TrunksSigL1: 2MBps Trunks

31


Typical Configuration

TS 0 TS 1-15 TS16 TS 17-31

TS = Time slot

TS# Used for

0

1-15

16

17-31

Frame Alignment /Error Checking /Signaling

Traffic

CCS7 Signaling (Other TS may also the used)

Traffic

2MBps Trunks2MBps Trunks

32


Abis (LAPD) InterfacesAbis (LAPD) Interfaces

FlagAddressControlInformationFrame check Sequence

Flag

last bit first bit

33


OSI Layers

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Link

1 Physical

CCS7 Levels

MTP Level 1 2 Mb/s Trunk

MTP Level 3

TUP

SCCP

BSSAP(DTAP+BSSMAP)ISUP

MAP

TCAP

MTP Level 2

ITU Signaling System CCS7 ITU Signaling System CCS7

34


Abbreviation of CCS7Abbreviation of CCS7

MTP Message Transfer Part TCAP Transaction Capabilities Application Part SCCP Signaling Connection Control Part TUP Telephone User Part ISUP ISDN User Part MAP Mobile Application Part BSSAP Base Station System Application Part BSSMAP BSS Management Application Part DTAP Direct Transfer Application Part

MTP Message Transfer Part TCAP Transaction Capabilities Application Part SCCP Signaling Connection Control Part TUP Telephone User Part ISUP ISDN User Part MAP Mobile Application Part BSSAP Base Station System Application Part BSSMAP BSS Management Application Part DTAP Direct Transfer Application Part

35








Service Area and Number PlanningService Area and Number Planning


Radio Technologies


36





Identify the system identification number

Identify the of mobile identification number

Identify the cell identification number


37



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: Service AreaService Area

PLMN service area

......

System area PLMN service area

MSC service area...

Location area...

Base station area...

Radio cell

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

MSC service area...

Location area...

Base station area...

Radio cell

PLMN service area

38



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: MSC/VLR NumberMSC/VLR Number

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

NDC ： National Destination Code. For example: The NDC of China Mobile is 139 、 138 、 137 、 136 、 135.

LSP(locally significant part): is defined by Telecom operator.For example: 86-139-00311

CC NDC LSP

MSC/VLR number

39



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: HLR NumberHLR Number

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

NDC ： National Destination Code. For example: The NDC of China Mobile is 139 、138 、 137 、 136 、 135.

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

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

NDC ： National Destination Code. For example: The NDC of China Mobile is 139 、138 、 137 、 136 、 135.

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

40



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: LAILAI

Location Area Identification

The LAI is the international code for a location area.

MCC ： Mobile Country Code ， It consists of 3 digits . For example: The MCC of China is "460"MNC ： Mobile Network Code ， It consists of 2 digits . For example: The MNC of China Mobile is "00"LAC ： Location Area Code ， It is a two bytes BCD

code(hex). The value 0000 and FFFF is invalid.For example: 460-00-0011

MCC ： Mobile Country Code ， It consists of 3 digits . For example: The MCC of China is "460"MNC ： Mobile Network Code ， It consists of 2 digits . For example: The MNC of China Mobile is "00"LAC ： Location Area Code ， It is a two bytes BCD

code(hex). The value 0000 and FFFF is invalid.For example: 460-00-0011

MCC MNC LAC

41



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: CGICGI

The CGI is a unique international identification for a

cell

The format is LAI+CI

LAI: Location Area Identification

CI ： Cell Identity. This code uses two bytes BCD

code(hex) to identify the radio cells within an LAI.

For example : 460-00-0011-0001

The CGI is a unique international identification for a

cell

The format is LAI+CI

LAI: Location Area Identification

CI ： Cell Identity. This code uses two bytes BCD

code(hex) to identify the radio cells within an LAI.

For example : 460-00-0011-0001

CGI: Cell Global Identification

42



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: BSICBSIC

NCC ： PLMN network color code. It comprises 3 bit. It allows various neighboring PLMNs to be distinguished.BCC ： BTS color code. It comprises 3 bit. It allows distinction between different radio frequency channels using the same frequency in neighboring cells.

NCC ： PLMN network color code. It comprises 3 bit. It allows various neighboring PLMNs to be distinguished.BCC ： BTS color code. It comprises 3 bit. It allows distinction between different radio frequency channels using the same frequency in neighboring cells.

NCC BCC

BSIC

BSIC （ Base Station Identification Color Code)

43




CC ： Country Code. For example: The CC of China is "86".NDC ： National Destination Code. For example: The NDC of

China Telecom is 139, 138, 137, 136, 135.SN ： Subscriber Number. Format:H0 H1 H2 H3 ABCDExample: 86-139-0666-1234

CC ： Country Code. For example: The CC of China is "86".NDC ： National Destination Code. For example: The NDC of

China Telecom is 139, 138, 137, 136, 135.SN ： Subscriber Number. Format:H0 H1 H2 H3 ABCDExample: 86-139-0666-1234

MSISDNMSISDN

CC NDC SN

National (significant)Mobile number

Mobile station internationalISDN number

44




MCC ： Mobile Country Code ， It consists of 3 digits . For example: The MCC of China is "460" 。MNC ： Mobile Network Code ， It consists of 2 digits . For example: The MNC of China Telecom is "00" 。MSIN ： Mobile Subscriber Identification Number. H1H2H3 S

ABCDEF For example: 666-9777001NMSI ： National Mobile Subscriber Identification ， MNC and MSIN

form it together. For Example of IMSI : 460-00-666-9777001

MCC ： Mobile Country Code ， It consists of 3 digits . For example: The MCC of China is "460" 。MNC ： Mobile Network Code ， It consists of 2 digits . For example: The MNC of China Telecom is "00" 。MSIN ： Mobile Subscriber Identification Number. H1H2H3 S

ABCDEF For example: 666-9777001NMSI ： National Mobile Subscriber Identification ， MNC and MSIN

form it together. For Example of IMSI : 460-00-666-9777001

Not more than 15 digits

3 digits 2 digits

IMSI

MCC MNC MSIN

NMSI

IMSI IMSI

45




The TMSI is assigned only after successful subscriber authentication.

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

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

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

The TMSI is assigned only after successful subscriber authentication.

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

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

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

TMSITMSI

TMSI: Temporary Mobile Subscriber Identification)

46



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: IMEIIMEI

TAC FAC SNR SP

IMEI

TAC ： Type approval code. It is administered by the type approval center.

FAC ： Final assembly code.It is administered by the manufacturer.

SNR ： Serial number.It is issued by the manufacturer of the MS.

SP ： Not used.

TAC ： Type approval code. It is administered by the type approval center.

FAC ： Final assembly code.It is administered by the manufacturer.

SNR ： Serial number.It is issued by the manufacturer of the MS.

SP ： Not used.

IMEI: International Mobile Station Equipment Identification

47



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: MSRN/HONMSRN/HON

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 taken from a pool of numbers specially reserved for MSRN.

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 taken from a pool of numbers specially reserved for MSRN.

MSRN: Mobile Subscriber Roaming Number

HON: Hand-over Number

48



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: RSZIRSZI

CC 、 NDC: same as that of MSISDN

ZC(Zone Code): is designed by telecom operator and

stored in the VLR.

CC 、 NDC: same as that of MSISDN

ZC(Zone Code): is designed by telecom operator and

stored in the VLR.

RSZI (Regional Subscription Zone Identity)

NDCCC ZC

RSZI

Zone Code, Two octets

49



haoxiuyan:haoxiuyan:haoxiuyan:haoxiuyan: Contents Contents





Channels on The Air InterfaceChannels on The Air Interface

Radio Technologies


50


Understand the structure of multiframes



Name the 4 most commonly used channel combinations

Identify the types of physical channels and logical channels

51


The physical channel is the medium over which the information is carriedThe logical channels consist of the information carried over the physical channel

The physical channel is the medium over which the information is carriedThe logical channels consist of the information carried over the physical channel

00 1 2 3 4 5 6 7

TDMA FRAME

Timeslot

The information carried in one time slot is called a “burst”

The information carried in one time slot is called a “burst”

Physical and Logical ChannelsPhysical and Logical Channels

52


Traffic ChannelTraffic Channel

TCHTraffic Channels

Speech

TCH/FS

Data

TCH/HSTCH/9.6 TCH/2.4

TCH/4.8

Normal Burst

TCH Traffic ChannelTCH/FS Full rate Speech Channel TCH/HS Half rate Speech Channel TCH/9.6 Data Channel 9.6kb/sTCH/4.8 Data Channel 4.8kb/sTCH/2.4 Data Channel 2.4Kb/s

53


FCCHSCH

CCH Control Channels

DCCH

SDCCH

BCCH

BCCH Synch. CH.ACCH

SACCHFACCH CCCH

RACHCBCH

PCH/AGCH

Broadcast Control Channel – BCCHCommon Control Channel – CCCHDedicated Control Channel – DCCHAssociated Control Channel – ACCH

Control ChannelControl Channel

54


CCH

BCCH downlink only

BCCH Synch.

Channels

SCH FCCH

The information carried on the

BCCH is monitored by the mobile

periodically when it is switched

on and not in a call

BCCH:Broadcast Control Channel

FCCH: Frequency Correction

Channel

SCH: Synchronization Channel

The information carried on the

BCCH is monitored by the mobile

periodically when it is switched

on and not in a call

BCCH:Broadcast Control Channel

FCCH: Frequency Correction

Channel

SCH: Synchronization Channel

Broadcast Control Channel – BCCHBroadcast Control Channel – BCCH

55


CCH

CCCH

RACHuplink

CBCH downlink

PCH/AGCHdownlink

The CCCH is responsible for transferring control information between all mobiles and the BTS.

RACH: Random Access Control Channel

PCH: Paging Channel

AGCH: Access Grant Control Channel

CBCH:Cell Broadcast Channel

The CCCH is responsible for transferring control information between all mobiles and the BTS.

RACH: Random Access Control Channel

PCH: Paging Channel

AGCH: Access Grant Control Channel

CBCH:Cell Broadcast Channel

Common Control Channel – CCCHCommon Control Channel – CCCH

56


CCH

DCCH

SDCCH

FACCH SACCH

DCCH is assigned to a single mobile connection for call setup or for measurement and handover purpose.SDCCH: Standalone Dedicated Control Channel ACCH: Associated Control Channel SACCH: Slow Associated Control Channel FACCH:Fast Associated Control Channel

DCCH is assigned to a single mobile connection for call setup or for measurement and handover purpose.SDCCH: Standalone Dedicated Control Channel ACCH: Associated Control Channel SACCH: Slow Associated Control Channel FACCH:Fast Associated Control Channel

ACCH

Dedicated Control Channel – DCCH Dedicated Control Channel – DCCH

57


Search for frequency correction pulse

Search for synchronous pulse

Unscramble system information

Snoop into paging message

Send access pulse

Allocate signaling channel

Set up the call

Allocate voice channel

Conversation

Release the call

FCCH

SCH

BCCH

PCH

RACH

AGCH

SDCCH

FACCH

TCH

FACCH

Power-off state

Idle state

Dedicated mode

Idle state

How to use these channel?How to use these channel?

58


Call Setup FlowCall Setup FlowMS BTS BSC MSC

Channel_req Channel_RequiredChannel_Active

Channel_Active_Ack

IMMEDIATE ASSIGN COMMANDEstablish_IND(CM Service Req)First SABM

CM Service Accepted

CR(Complete_L3_information)

CC

Setup

Call Processing

ASSIGNMENT COMMANDFirst SABM Establish_IND

Channel_ActiveChannel_Active_Ack

Assignment_Req

Assignment_CMPASSIGNMENT CMP

Alerting

Connect

Connect Ack

Disconnect

Release

Release CompleteClear_CMDClear_CMP

Conversation

SABM: Set asynchronous balanced mode command--Initial access frame

UA: Unnumbered acknowledgement response

59


GSM MultiframeGSM Multiframe

TDMA Frames

0 1

0 1 2 43 21 22 23 2524

26 – Frame Multiframes

0 1 10

TRAFFIC CHANNELS

2 3 4 5 6 7 2 3 5 764

60


TCH MultiframeTCH Multiframe

IDLE

SACCH

IDLE

SACCH

25

12

0

This is used to transmit a Traffic Channel Combination (TCH/ SACCH/FACCH). The FACCH is not showed in the diagram as it does not receive its own time allocation. The FACCH steals a time period from the TCH is required.

The 13th frame is used by the SACCH which carriers link control information to and from the mobile and BTS.

The 26th frame is idle.

This is used to transmit a Traffic Channel Combination (TCH/ SACCH/FACCH). The FACCH is not showed in the diagram as it does not receive its own time allocation. The FACCH steals a time period from the TCH is required.

The 13th frame is used by the SACCH which carriers link control information to and from the mobile and BTS.

The 26th frame is idle.

Downlink Uplink

25

12

0

61


TDMA Frames

0 1

0 1 2 43 46 47 48 5049

51 – Frame Multiframes

0 1 10

CONTROL CHANNELS

2 3 4 5 6 7 2 3 5 764

GSM MultiframeGSM Multiframe

62


BCCH/CCCH MultiframeBCCH/CCCH Multiframe

F SB B B B

C C C C F F S C C C C C C C CI

Downlink

0 10 20 30 40 50

S C C .. F S C C .. F S C C ..

R R R R R R R R R R R R R R R R R R R R R R

Uplink

R R R .. R R R ..R R R ..

0 10 20 30 40 50

F = FCCH (Frequency) S = SCH (Sync.)C = CCCH (Common)I = Idle R = RACH (Random)

63


D0 D1 D7 A0 A3 I I I

D0 D1 D6 D7 A4 A7 I I I

A5 A6 D0 D7 A0A7 I I I

A1 A2 D0 D7 A4A3 I I I

Downlink

0 7 24 32 44 50

0 7 12 15 44 50

Uplink

D = SDCCH/8 (Dedicated) A = SACCH/C8 (Associated) I = Idle

D6

SDCCH MultiframeSDCCH Multiframe

64


Timeslots and TDMA FramesTimeslots and TDMA Frames

Higher Capacity Cell

Broadcast TrafficDedicated

Traffic00 1 2 3 4 5 6 7

00 1 2 3 4 5 6 7

Low Capacity Cell

Combined Traffic00 1 2 3 4 5 6 7

65


Combined MultiframeCombined Multiframe

BSF C CSF C D0SF D1 D2SF D3 A0S A1F I

BSF C CSF C D0SF D1 D2SF D3 A2S A3F I

0 2 6 10 20 30 40 50

Downlink

D3 RR A2 A3 RR R D0 D1 RR D2R

0 4 6 10 20 30 40 50

D3 RR A2 A3 RR R D0 D1 RR D2R

Uplink

R = RACH (Random) B = BCCH (Broadcast)F = FCCH (Frequency) S = SCH (Sync.)C = CCCH (Common) D = SDCCH/4 (Dedicated)A = SACCH/4 (Associated) I = Idle

66


Configuration SuggestionConfiguration Suggestion

Just one BCCH for one cell

FR: One SDCCH for two TRXs

HR: One SDCCH for one TRX

67










Radio TechnologiesRadio Technologies


68


On completion of this section you will be able to know about the following radio technologies :

GMSK Modulation Techniques

Power Control

VAD, DTX, DRX

Diversity

Frequency Hopping


69


Modulation TechniquesModulation Techniques

– phase modulation can be implemented easily for digital signals, this is the method which is used for the GSM air interfaces. Phase Modulation is known as Phase Shift Keying when applied to digital signals

– phase modulation can be implemented easily for digital signals, this is the method which is used for the GSM air interfaces. Phase Modulation is known as Phase Shift Keying when applied to digital signals

Amplitude Modulation (AM)

Frequency Modulation (FM)

Phase Modulation (PM)

70


1 0 0 1 1 GaussianDigital Filter

Phase Modulator

Gaussian Minimum Shift Keying (GMSK) Gaussian Minimum Shift Keying (GMSK)

71


8PSK – for EDGE8PSK – for EDGE

Modulating bits

D3i, d3i+1, d3i+2

Symbol

parameter l

(1,1,1) 0

(0,1,1) 1

(0,1,0) 2

(0,0,0) 3

(0,0,1) 4

(1,0,1) 5

(1,0,0) 6

(1,1,0) 7

EDGE:EDGE:

Enhanced Data Rates For GSM Evolution)Enhanced Data Rates For GSM Evolution)

72


Power ControlPower Control

Saves radio battery powerReduces co-channel andadjacent channel interference

8W

0.8W

5W

Both Uplink and Downlink power settings can be controlled independently and individually.

73


Battery LifeBattery Life

Voice Activity Detection – VAD

Discontinuous Transmission – DTX

Discontinuous Reception – DRX

Power Control

74


VAD & DTXVAD & DTX

Encoding the speech silences at a rate of 500 bit/s rather than the full 13Kb/s.

If the mobile does not transmit during ‘silence’ there is a reduction in the overall power output requirement

Without DTX

With DTX

Comfort Noise

75


DRXDRX

DRX allows the mobile station to effectively “switch off” during times when reception is deemed unnecessary.

P P P P P P BCCH P P

BCCH Multiframe P = Paging Channel

MS Being paged

MS in listen mode

MS receive System

information

MS in listen mode

76


Multipath FadingMultipath Fading

•Diversity

•Frequency Hopping

Time Dispersion

77


DiversityDiversity

When diversity is implemented two antennas are situated at the receiver. These antennas are placed several wavelengths apart to ensure minimum correlation between the two receive paths.

The two signals are then combined, this ensures that a low signal strength is less likely to occur.

Compare oradd signals

Resultant Signal

Approx. 10 wavelengths

78


Frequency HoppingFrequency Hopping

Synthesizer Hopping:each timeslot on a given transceiver can transmit at a different frequency

Baseband Hopping: each transceiver stays at the same frequency and the data is switched to the appropriate transceiver.

Each time the BTS or mobile transmits a burst, it does so on a different RF carrier frequency.

time

frequency

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Radio Technologies

The Future DevelopmentThe Future Development

80


Objectives Objectives


State the future development of digital cellular mobile system

81


GSM will stay in the Lead, all professional Market Forecasts say

0

50

100

150

200

250

300

1996 1997 1998 1999 2000 2001

GSM users world wide in millions

GSM User World WideGSM User World Wide

82


Service amout

Time

Data

Voice

Today 2000

Voice and Data ServiceVoice and Data Service

83


Mobile Communication and Internet Mobile Communication and Internet

100200300400500600700

1995 1996 1997 1998 1999 2000 2001

Mobile Internet

million

84


1999 2000 2001

57.6 kbps

115 kbps

384 kbps

2Mbps

GSM

HSCSD

GPRS

EDGE

IMT-2000

9.6 kbps

2G

2.5G

3G

GSM Develop PathGSM Develop Path

85


Data rate of EDGE and GPRSData rate of EDGE and GPRS

8PSKGMSK

8.0

12.014.4

20.0

8.811.2

14.817.6

22.4

29.6

44.8

54.4

59.2

0.0

10.0

20.0

30.0

40.0

50.0

60.0

CS-1 CS-2 CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8 MCS-9

Kbps

GPRSEGPRS

86


Downlink, 4 TS, MCS-9 ：

Huawei EDGE Test ResultHuawei EDGE Test Result

87







Radio Technologies


SummarySummary

88


Oma000001 gsm fundamentals issue3.3

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