MOBILE COMMUNICATIONS

PRESENTED BY:  MIHIR RAO  SWAPNIL RANE  AMOL HATKAR  MAZHAR NOORI  SYED JAVED  AATIF MODAK  AZEEM HASHMANI  MUBIN

COMMUNICATION ABOUT:  IT IS THE PROCESS WHEREBY THE MEANINGFUL INFORMATION IS TRANSFERRED FROM ONE POINT (LOCATION) CALLED SOURCE IN SPACE TO THE OTHER POINT (LOCATION) CALLED DESTINATION (OR USER).  IT IS A TWO -WAY TRANSMISSION & RECEPTION OF DATA STREAMS.  THE SCIENCE OF COMMUNICATION INVOLVING LARGE DISTANCE IS CALLED TELE-COMMUNICATION. TYPES:  WIRE (OR LINE) COMMMUNICATON.  WIRELESS (OR RADIO) COMMUNICATION. (MOBILE COMMUNICATION COMES UNDER WIRELESS COMMUNICATION)

FREQUENCY BANDS FOR MOBILE COMMUNICATION  THE CURRENT FREQUENCY SPECTRUM ALLOCATION FOR CELLULAR MOBILE RADIO IN USA IS 50MHz WITHIN THE 824 TO 849 MHz AS UP-LINK FREQUENCY BAND & 869 TO 894 MHz AS DOWN-LINK FREQUENCY BANDS.  50MHz LEADS TO TOTAL OF 832 FULL DUPLEX CHANNELS. OUT OF WHICH 416 CHANNELS, 21 CHANNELS ARE USED AS SETUP (CONTROL) CHANNELS, WITH REMAINING 395 CHANNELS FOR USER TRAFFIC.  THE OTHER 416 CHANNELS ARE SHARED BY TWO OPERATORS NAMELY WIRELESS COMMON CARRIER (WCC) & THE RADIO COMMON CARRIER (RCC).

TYPES OF MODULATIONS USED  THE FIRST GENERATION (1G)(ANALOG) CELLULAR SYSTEMS USE FM FOR SPEECH TRANSMISSION & FSK FOR SIGNALING.  THE SECOND GENERATION (2G)(DIGITAL) CELLULAR SYSTEMS ARE BASED ON TDMA & CDMA TECHNOLOGY USE PCM WITH VOICE TRANSMISSION RATE OF 24 KBPS OR HIGHER FOR COMMERCIAL USES.  THE GSM TECHNOLOGY WHICH IS USED ALMOST WORLD WIDE.IT USES TDMA & FDMA FOR MODULATIONS.  GSM EDGE (ENHANCED DATA RATES FOR GSM EVOLUTION) IS THE THIRD GENERATION (3G) VERSION NEWLY USED.

BASIC MOBILE TELEPHONE SERVICE NETWORK

GENERAL BLOCK DIAGRAM OF A CELULLAR RADIO

CELLULAR CONCEPT  A SMALL GEOGRAPHIC COVERAGE AREA OF A BASE STATION WITH A DIAMETER OF 2 TO 50 KM EACH OF WHICH A NUMBER OF RF CHANNELS IS CALLED A CELL.  GEOMETRIC SHAPES OF CELL ARE: A SQUARE, AN EQUILATERAL TRIANGLE, A HEXAGON. A HEXAGONAL CELL

CELLULAR SYSTEM ARCHITECTURE

FREQUENCY REUSE  THE DESIGN PROCESS OF SELECTING & ALLOCATING RF CHANNEL GROUPS FOR ALL OF THE CELLULAR BASE STATIONS WITHIN A CELLULAR SYSTEM IS CALLED FREQUENCY REUSE OR FREQUENCY PLANNING.

CELL SPLITTING

HANDOFF MECHANISM

WIRELESS COMMUNICATION TECHNIQUES  THERE ARE THREE IMPORTANT TECHNIQUES ; 1) CDMA (CODE DIVISION MULTIPLE ACCESS). 2) FDMA (FREQUENCY DIVISION MULTIPLE ACCESS). 3) TDMA (TIME DIVISION MILTIPLE ACCESS).  FROM THE ABOVE TECHNIQUES, CDMA IS THE MOST USED & IMPORTANT ONE.

CDMA (METHODS & VERSIONS)  CODING METHODS: 1) AUTO CORRELATION CODES. 2) ORTHOGONAL CODES. 3) WALSH CODES. 4) SCRAMBLING CODES. 5) CHANNELIZATION CODES. 6) CARRIER MODULATION CODES.  CDMA VERSIONS: 1) W-CDMA (WIDEBAND) 2) 3G CDMA ) TD-SCDMA (TIME DIVISION- SYNCHRONOUS)

GSM TECHNOLOGY HISTORY  THE CONFERENCE OF EUROPEAN POSTAL & TELECOMMUNICATIONS ADMINISTRATIONS (CEPTA) DEVELOPED THE GSM STANDARDS FOR TDMA SYSTEM IN JUNE  THEY MADE IT TO SERVE TWO MAIN OBJECTIVES; 1) EUROPEAN ROAMING THROUGHOUT THE CONTINENT, 2) INTERACTION WITH ISDN.  THE FIRST COMMERCIAL GSM SYSTEM CALLED D 2, WAS IMPLEMENTED IN GERMANY IN 1992.

GSM FREQUENCY RANGES  MOST ‘2G’ GSM NETWORKS OPERATE IN 900MHz TO 1800MHz BANDS.  MOST EUROPEAN ‘3G’ GSM NETWORKS OPERATE IN 2100MHz BANDS.  ‘2G’ GSM USES 890 TO 915 MHz FOR UPLINK & 925 TO 960 MHz FOR DOWNLINK PRONIDING 125 RF CHANNELS SPACED AT 200KHz. DUPLEX SPACING OF 45 MHz IS USED.  THEY HANDLE LOW SPEED DATA SERVICES (UPTO 9.6 KBPS).

GSM SERVICES  TELESERVICES: SMS, EMREGENCY CALLING,FAX,MMS,VIDEOTEX,TETLTEX  BEARER (OR DATA) SERVICES: FULL DUPLEX, TRANSPARENT, NON TRANSPARENT DATA TX.,SYNCHRONOUS OR ASYNCHRONOUS PACKAGE DATA (GPRS).  SUPPLEMENTARY (ISDN) SERVICES: CALLER ID, CALL WAITING, CALL HOLD, CALL BARRING, CLOSED USER GROUP, TELE- CONFERENCING ETC..

GSM ARCHITECTURE

SUBSCRIBER INDENTITY MODULE (SIM)  In addition to the battery, GSM mobile phones require a small microchip, called a Subscriber Identity Module or SIM CARD, to function. microchip  the SIM Card is usually placed underneath the battery in the rear of the unit, and (when properly activated) stores the phone's configuration data, and information about the phone itself, such as which calling plan the subscriber is using.  When the subscriber removes the SIM Card, it can be re-inserted into another phone that is configured to accept the SIM card [16] and used as normal. [16]

CALL FLOW SEQUENCE THE TYPICAL SIGNALING SEQUENCES FOR CALL FLOW IN GSM ARE AS FOLLOWS:  LOCATION UPDATING.  MOBILE CALL ORIGINATION.  MOBILE CALL TERMINATION  AUTHENTIFICATION & CIPHERING.  INTER-MSC CALL HANDOFF.

MOBILE CALL ORIGINATION IN GSM

MOBILE CALL TERMINATION IN GSM

ADVANTAGES:  HIGH COVERAGE RANGE & AREA.  GOOD SPEECH QUALITY.  LARGE VARIETY OF DATA & SUPPLEMENTARY SERVICES.  PROVIDES SEAMLESS GLOBAL ROAMING. APPLICATIONS:  PAGING & SMS’s  & INTERNET ACCESS  INVENTORY CONTROL  DATA INPUTS.  CREDIT CARD AUTHORIZATIONS (FROM REMOTE LOCATIONS )

REFERENCES WEBSITES:    BOOKS:  MOBILE COMMUNICATION BY V.G. YANGALVAR, R.C. JAISWAL, & GANESH B. AKOLIYA

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