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Introduction
History of Mobile Communication
Mobile phones have their roots in radiophones.

 Radiophones have a long and varied history going back to Reginald Fessenden’s invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephony links and civil services in the 1950s, while hand-held cellular radio devices have been available since 1973.
 Due to their low establishment costs and rapid deployment, mobile phone networks have since spread rapidly throughout the world, outstripping the growth of fixed telephony.
 The concepts of frequency reuse and handoff as well as a number of other concepts that formed the basis of modern Cell Phone or mobile phone.
 Cellular technology
 Cellular Technology - Telephony, a generic for all wireless phones, and cellular, a term derived from cellular base stations that control phone calls, are a combination of technologies that allow for mobile phone transmission and reception in a given area.
 Generation of mobile phones
 First Generation
 First Generation Mobile Phones (Also known as 1G ) came into vogue first in the United States of America in 1973.
 It used analog signals and hence needed more than one base stations which were closely located.
 The first handheld mobile phone to become commercially available to the US market was the Motorola DynaTAC 8000X which received approval in 1983.
 Mobile were too robust and heavy, they were static and designed for permanent installation in vehicles.
 Features of First generation
 Analog voice signaling was use.
 Less Secure
 Not much reliable networks.
 No SMS and Roaming Facility.
 Example: Advanced Mobile Phone System (AMPS) is the analog mobile phone system standard developed by Bell Labs.
 Second Generation
 Second Generation Mobile Phones (Also known as 2G ) adopt the system of digital signaling in order to establish a connection between the radio towers.
 first digital cellular phone call was made in the United States in 1990 and still in use.
 Second Generation Mobile Phones were digital circuit and the use of advanced and fast phone to network signaling.
 Frequency was much higher.
 Features of 2G
 GSM – GLOBAL SYSTEM FOR MOBILE COMMUNICATION
 GSM technology which stands for GLOBAL SYSTEM FOR MOBILE COMMUNICATION, The GSM belonging to TDMA is the most widely used technology across the world and was first started in Finland
 Phase I of GSM specifications was published in 1990
 International demand was so great that the system name was changed from Groupe Special Mobile to Global Systems for Mobile Communications (still GSM).
 Commercial service started in mid-1991
 1992 first paying customers were signed up for service.
 By 1993 there were 36 GSM networks in 22 countries
 Early 1994 there were 1.3 million subscribers worldwide
 By 1996 there were more than 25 million subscribers worldwide
 By October 1997 it had grown to more than 55 million subscribers worldwide
 System Architecture
 System Architecture
 System Architecture
Mobile Station (MS)
Mobile Equipment

 Produced by many different manufacturers
 Must obtain approval from the standardization body
 Uniquely identified by an IMEI (International Mobile Equipment Identity
Subscriber Identity Module (SIM)
 Smart card containing the International Mobile Subscriber Identity (IMSI)
 Allows user to send and receive calls and receive other subscribed services
 Encoded network identification details
 Protected by a password or PIN
 Can be moved from phone to phone – contains key information to activate the phone
Base Station Subsystem is composed of two parts that communicate across the standardized Abis interface allowing operation between components made by different suppliers
 Base Transceiver Station (BTS)
 Base Station Controller (BSC)
Base Transceiver Station (BTS)
 Houses the radio transceivers that define a cell
 Handles radio-link protocols with the Mobile Station
 Speech and data transmissions from the MS are recoded
 Requirements for BTS:
• ruggedness
• reliability
• portability
• minimum costs
Base Station Controller (BSC)
 Manages Resources for BTS
 Handles call set up
 Location update
 Handover for each MS
 System Architecture
Network Subsystem
Mobile Switching Center (MSC)

 Switch speech and data connections between:
• Base Station Controllers
• Mobile Switching Centers
• GSM-networks
• Other external networks
 Heart of the network
 Three main jobs:
 1) connects calls from sender to receiver
 2) collects details of the calls made and received
 3) supervises operation of the rest of the network components
Home Location Registers (HLR)
 Contains administrative information of each subscriber
 Current location of the mobile
Visitor Location Registers (VLR)
 contains selected administrative information from the HLR
 authenticates the user
 tracks which customers have the phone on and ready to receive a call
 periodically updates the database on which phones are turned on and ready to receive calls
Authentication Center (AUC)
 Mainly used for security
 Mata storage location and functional part of the network
 Ki is the primary element
Equipment Identity Register (EIR)
 Database that is used to track handsets using the IMEI (International Mobile Equipment Identity)
 Made up of three sub-classes: The White List, The Black List and the Gray List
 Optional database
Basic Features Provided by GSM
Advanced Features Provided by GSM
Present scenario

 2.5G is a stepping stone between 2G and 3G cellular wireless technologies.
 2.5G provides some of the benefits of 3G (e.g. it is packet-switched) and can use some of the existing 2G infrastructure such as GSM networks.
 GPRS and EDGM services got introduced due to the increase in the demand of internet. Currently we are in 2.5G which comprises of GSM, EDGM and GPRS.
GPRS

 Stand for General Packet Radio Service
 packet oriented Mobile Data Service available to users of Global System for Mobile Communications (GSM).
 Provide Internet communication services such as email and World Wide Web access.
 Always connected and send data immediately
 higher speeds: typically 32-48 kbps.
 GPRS data is handled as a series of "packets" that can be routed over several paths through the network, rather than as a continuous bit-stream.
 the information is split into separate but related "packets" before being transmitted and reassembled at the receiving end.
EDGE
 Stands for Enhanced Data rates for GSM Evolution.
 maximum data transfer rate of 384 kbps
 EDGE offers the best that can be achieved with a 2.5G network
Future -- UMTS (Universal Mobile Telephone System)
 Reasons for innovations
 new service requirements
 availability of new radio bands
 User demands
 seamless Internet-Intranet access
 wide range of available services
 compact, lightweight and affordable terminals
 simple terminal operation
 open, understandable pricing structures for the whole spectrum of available services
3rd Generation
 3G was introduced in the United States early in 2002.
 send data up to 40 times the rates of earlier digital networks.
 Applicable to mobile as well as fixed wireless systems.
 Should be operational on, above and below the earth.
 Example: UMTS
Potential for 3G
Possibilities with 3G

 Mobile internet connectivity.
 Mobile e-mail.
 Multimedia services such as digital photos.
 Wireless application downloading.
 Video on demand.
 Real-time multiplayer gaming.
 Enhanced emergency and location based service.
 Push to talk & push to video message.
 Voice/high quality audio.
 E-Commerce
Evolution of 3G
I.T.U.
 I.T.U.
 Leading UN agency for Information & Communication.
 Organizes Telecom events.
 Includes 191 member states and more than 700 sector members and associates.
 Made a 3G standard called IMT-2000
IMT 2000
 Single global wireless standard.
 linking of diverse systems of terrestrial and/or satellite based networks.
Various 3G services used across the world
 Mobile T.V. based on video streaming, T-Mobile (Germany).
 Mobile Earth for navigation, Vodafone (Germany).
 Mobile Radio based on audio streaming, TELUS Mobility (Canada).
 Banking & Finance services, Telstra (Australia).
Network Architecture
W-CDMA

 Technology behind UMTS
 Closely linked to GSM standard
 It was evolved by 3GPP
 Was finalized in 1999
W-CDMA layers
W-CDMA Spreading
Technical Specifications

 Chip Rate 3.84 Mcps.
 UMTS uses 15 slots per frame.
 Adaptive power control based on SIR.
 Smart antennas can be used to increase capacity and coverage.
 QPSK Modulation
 Frequency band 1920-1980 MHz and 2110-2170 MHz.
 Channel Bit Rate 5.76 Mbps.
 Frame length is 10 ms(38400 chips).
 Number of Chips per slot is 2560
W-CDMA has Two modes of Operation
TDD

 Time-division duplexing (TDD) is the application of time-division multiplexing to separate outward and return signals. It emulates full-duplex communication over a half-duplex communication link
 In this method uplink and downlink transmission are carried over the same frequency band using synchronized time intervals.
FDD
 The uplink and downlink transmissions employ two different frequency band. A pair of frequency band with specified separation is assigned for a connection
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Mobile Communications
Chapter 1: Introduction
Computers for the next century?
Computers are integrated

 small, cheap, portable, replaceable - no more separate devices
Technology in the background
 computer are aware of their environment and adapt (“location awareness”)
 computer recognize the location of the user and react appropriately (e.g., call forwarding, fax forwarding)
Advances in technology
 more computing power in smaller devices
 flat, lightweight displays with low power consumption
 new user interfaces due to small dimensions
 more bandwidth per cubic meter
 multiple wireless interfaces: wireless LANs, wireless WANs, regional wireless telecommunication networks etc. („overlay networks“)
Mobile communication
Aspects of mobility:
 user mobility: users communicate (wireless) “anytime, anywhere, with anyone”
 device portability: devices can be connected anytime, anywhere to the network
Wireless vs. mobile Examples
û û stationary computer
û ü notebook in a hotel
ü û wireless LANs in historic buildings
ü ü Personal Digital Assistant (PDA)
The demand for mobile communication creates the need for integration of wireless networks into existing fixed networks:
 local area networks: standardization of IEEE 802.11,
ETSI (HIPERLAN)
 Internet: Mobile IP extension of the internet protocol IP
 wide area networks: e.g., internetworking of GSM and ISDN
Applications
Vehicles
 transmission of news, road condition, weather, music via DAB
 personal communication using GSM
 position via GPS
 local ad-hoc network with vehicles close-by to prevent accidents, guidance system, redundancy
 vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for maintenance
Emergencies
 early transmission of patient data to the hospital, current status, first diagnosis
 replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc.
crisis, war,
Travelling salesmen
 direct access to customer files stored in a central location
 consistent databases for all agents
 mobile office
Replacement of fixed networks
 remote sensors, e.g., weather, earth activities
 flexibility for trade shows
 LANs in historic buildings
Entertainment, education, ...
 outdoor Internet access
 intelligent travel guide with up-to-date location dependent information
 ad-hoc networks for multi user games
Location dependent services
Location aware services
 what services, e.g., printer, fax, phone, server etc. exist in the local environment
Follow-on services
 automatic call-forwarding, transmission of the actual workspace to the current location
Information services
 „push“: e.g., current special offers in the supermarket
 „pull“: e.g., where is the Black Forrest Cherry Cake?
Support services
 caches, intermediate results, state information etc. „follow“ the mobile device through the fixed network
Privacy
 who should gain knowledge about the location
Wireless networks in comparison to fixed networks
Higher loss-rates due to interference
 emissions of, e.g., engines, lightning
Restrictive regulations of frequencies
 frequencies have to be coordinated, useful frequencies are almost all occupied
Low transmission rates
 local some Mbit/s, regional currently, e.g., 9.6kbit/s with GSM
Higher delays, higher jitter
 connection setup time with GSM in the second range, several hundred milliseconds for other wireless systems
Lower security, simpler active attacking
 radio interface accessible for everyone, base station can be simulated, thus attracting calls from mobile phones
Always shared medium
 secure access mechanisms importantEarly history of wireless communication Many people in history used light for communication
 heliographs, flags („semaphore“), ...
 150 BC smoke signals for communication;(Polybius, Greece)
 1794, optical telegraph, Claude Chappe
Here electromagnetic waves are of special importance:
 1831 Faraday demonstrates electromagnetic induction
 J. Maxwell (1831-79): theory of electromagnetic Fields, wave equations (1864)
 H. Hertz (1857-94): demonstrateswith an experiment the wave character of electrical transmission through space(1886, in Karlsruhe, Germany, at the location of today’s University of Karlsruhe)