Modulation Techniques in GSM

By

Foram Shah

Aswini B Naicker

Tamanna Goware (SAL Institute of Technology &

Engineering Research)

GLIMPSE

HISTORY OF GSMMODULATION METHODSCRITERIA OF SELECTION OF

MODULATION SCHEMEFUTURE TRENDSREFERENCESCONLUSION

GLIMPSE

1981 –EUROPEAN STANDARD FOR DIGITAL CELLULAR VOICE TELEPHONY CREATED MOBILE COMMITIES

1986 –EUROPEAN COMMISION PROPOSED RESERVING 900MHZ SPECTRUM BAND

1987 –OUT OF 15, 13 EUROPEAN COUNTRIES DEVELOPED A COMMON CELLULAR SYSTEM

1987–EUROPE PRODUCE FIRST GSM TECHNICAL SPECS IN FEBRUARY

1989 –SPECIAL MOBILE COMMITY WAS TRANFERED FROM CEPT TO ETSI

1991 –GSM WAS EXPENDED FOR 1800MHZ BAND

1992 –FIRST SMS WAS SENT

1995 –FAX, DATA AND SMS SERVICES WAS LAUNCHED, IN THESE YEAR GSM SUBSCRIBER EXCEDDED 10 MILLION’S

1996 –GSM PREPAID SIMCARD LAUNCHED

GLIMPSE

1998 –SUBSCRIBER EXCEDDED TO 100 MILLION

2000 –FIRST COMMERCIAL GPRS SERVICE WAS LAUNCHED

2001 –UMTS NETWROK WAS LAUNCHED, GSM SUBSCRIBER EXCEDDED 500 MILLION

2002 –FIRST MMS WAS INTRODUCED

2004 –SUBRISCBER EXCEDDED TO 1 BILLION

2005 –SUBRISCBER EXCEDDED TO 1.5 BILLION

2007 –HSPA WAS INTRODUCED

2008 –SUBRISCBER EXCEDDED TO 3 BILLION

2010 –80% OF THE GLOBAL MOBILE MARKET WAS COVERED BY GSM

WHAT IS MODULATION?

In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal (high frequency signal), with a modulating signal that typically contains information to be transmitted.

Process in which high frequency carrier signal is imposed on modulating signal.

TYPES OF MODULATION TECHNIQUES

Analog Modulation Techniques• Is applied continuously in

response to analog information signal

Types• AM• FM• Phase Modulation

MODULATION TECHNIQUES

ASK

FSK

PSK

WHAT IS DIGITAL MODULATION?

In digital modulation, an analog carrier signal is modulated by a discrete signal.

.

WHAT IS DIGITAL MODULATION?

1. ASK (AMPLITUDE SHIFT KEYING)

2. PSK (PHASE SHIFT KEYING)

3. FSK ( FREQUENCY SHIFT KEYING)

4. QAM (QUADRATURE AMPLITUDE MODULATION)

5. CONTINOUS PHASE MODULATION

WHY DIGITAL MODULATION?

SECURITY

GREATER FIELDITY

DISTANCE

ACCURATE OUTPUT

MORE INFORMATION CAPACITY

COMPATIBLE WITH DIGTIAL SERVICES

BETTER QUALITY COMMUNICATION

USE OF REPEATER

GMSK(GAUSSIAN MINIMUM SHIFT KEYING)

GMSKIn digital communication, Gaussian minimum shift keying or GMSK is a continuous-phase frequency-shift keying modulation scheme

GMSK= MSK + Gaussian FilterGaussian Frequency shaping filterModulation Index h= 1/2

Characterized by value of BTT= Bit durationB= 3dB bandwidth of shaping filterBT= 0.3 for GSM

MSK

GMSK MODULATOR

GMSK DEMODULATOR

GMSK

FREQUENCY DOMAIN RESPONSE TIME DOMAIN RESPONSE

COMPARISION

CRITERIA FOR SELECTION OF MODULATION SCHEME

CONCEPT

SOURCE CODING

ACTIVE MOBILE SUBSCRIBERS

SIGNAL SEPARATION

DIVERSITY

MULTIPLE ACCESS INTERFERENCE

FADING CHANNEL SENSITIVITY

BANDWIDTH EFFICIENCY

SYNCHRONISATION

VOICE & DATA INTEGRATION

FORMAT FLEXIBILITY

SYSTEM FLEXIBILITY & EXPANDABILITY

USER EQUIPMENT COMPLEXITY

SYSTEM COMPLEXITY

IMPLEMENTATION COMPLEXITY

CRITERIA FOR SELECTION OF MODULATION SCHEME

EVOLUTION

1GANALOG

2G&2.5G(GSM,GPRS & EDGE) 3G (DIGITAL)

Future Trends

First Generation

Mostly speech communication

Voice and data

Circuit switched

Local systems

Future Trends

Second Generation

Digital transmission

Mainly speech communication

Digital data

Circuit switched

Global roaming

Future TrendsThird Generation

Digital Transmission

Mainly speech communication

Increasing Digital Data

Increasingly packet switched

Global roaming

Future Trends

Next Generation

Digital transmission

Mainly speech & video communication

Mainly digital data

Mainly packet switched

Global roaming

4G,LTE5G

3G14.4kbps- 2Mbps

WCDMA384-2048kbps

2.75GEDGE

384kbps

2.5GGPRS

9.6-53.6kbps

HSCD9.6-28.8kbps

2GGSMData

9.6kbps

Future Trends

CONCLUSION

According to the needs & availability of wireless network along with reliability and security, the systems are evolving .

• With more processing power, packaging of data, the data speed per subscriber is increasing

More & more medias are encompassed in the mobile technology

• Continues…

REFRENCES

OUR REFERENCES

Wireless CommunicationsRappaport (Pearson Publication)Wireless CommunicationsTL Singhal (Tata Mc Graw Hills)

Paper on IEEE Standard 802.3ba in June 2010

ThankYou