SMARTPHONES AND MOBILE PHONE TECHNOLOGY MOBILE TECHNOLOGY BASICS. Lecture: 2 Instructor Mazhar Hussain

Transcription

1 SMARTPHONES AND MOBILE PHONE TECHNOLOGY MOBILE TECHNOLOGY BASICS Lecture: 2 Instructor Mazhar Hussain

2 WIRELESS AND MOBILE COMMUNICATION Blog 2

3 WHAT ARE WE TALKING ABOUT?? The world is flat! Bringing people together...? Changing the way things work.

4 "TEXT MESSAGES ARE LIKE LITTLE SUGAR RUSHES OF CONTACT, POSTCARDS FROM THE PEOPLE'S CYBERSPACE, THE REAL REASON GOD GAVE US THUMBS AND THE CAPACITY FOR LANGUAGE"

5 HISTORY - The first official mobile phone used in Sweden by the Swedish police in 1946; could make 6 phone calls before car's battery was drained - development of first cell phone (creation of towers/cells at Bell Labs in FCC? Motorola DynaTAC 8000X made commercially available: 2 lbs, $3, Motorola MicroTac Lite the lightest phone: $1,000

6 HISTORY CONT. - 2nd generation: from the early 1990's - smaller, better batteries, huge increase in popularity - 3rd generation: include 2 Megabits of maximum data rate indoors and 384 kbits for outdoor use - include internet access and other modern innovations IBM developed first smartphone, Simon

7 USES - Smartphones provide portable use of IT - Entertainment Uses: games, music (mp3 player), books (e-book), and digital television broadcast - Social Uses: phone call, text message, wireless internet (access to , social networking websites) - Organization Uses: calendar, finance manager, address book, storage for data

8 USES CONT. - Hospital Uses: used to view image (x-ray, MRI, etc). means of communication between nurses and clinicians. - Museum Uses: audio guide is provided through cell phones. - China: mobile learning provides access to lectures and test preps.

9 BENEFITS Mobile technology is key to keeping in touch in the modern world. Text messaging Smart Phones aren't only used for communication, but for organizing schedules, jotting down notes, playing music, games, checking the weather, and other applications.

10 BENEFITS CONT. Cell Phones "revolutionized long distance calling", making it much more inexpensive for long distance communication. Cell phone logs have also been helpful in court cases where they can be used as evidence. (You may also consider this a disadvantage)

11 CRITICISMS - negative health affects (increases resting blood pressure, reduces production of melatonin, related to Altzeimers's Disease, linked to cancer) -increased stress level (fatigue, headache, difficulty in concentration, disturbance in sleep) - effect on children; the "blackberry father" - risk in driving - reduced privacy - effects on language

12 SUMMARY/OPINION Mobile technology and smart phones play a major role in every day life, and their importance is expected to continue, and even increase in the future.

13 CELLULAR NETWORK BASICS There are many types of cellular services; before delving into details, focus on basics (helps navigate the acronym soup ) Cellular network/telephony is a radio-based technology; radio waves are electromagnetic waves that antennas propagate Most signals are in the 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz frequency bands 13 Cell phones operate in this frequency range (note the logarithmic scale)

14 EVOLUTION TO CELLULAR NETWORKS COMMUNICATION ANYTIME, ANYWHERE radio communication was invented by Nikola Tesla and Guglielmo Marconi: in 1893, Nikola Tesla made the first public demonstration of wireless (radio) telegraphy; Guglielmo Marconi conducted long ditance (over see) telegraphy 1897 in 1940 the first walkie-talkie was used by the US military in 1947, John Bardeen and Walter Brattain from AT&T s Bell Labs invented the transistor (semiconductor device used to amplify and switch electronic signals) AT&T introduced commercial radio comm.: car phone two way radio link to the local phone network in 1979 the first commercial cellular phone service was launched by the Nordic Mobile Telephone (in Finland, Sweden, Norway, Denmark).

15 CELLULAR NETWORK GENERATIONS It is useful to think of cellular Network/telephony in terms of generations: 0G: Briefcase-size mobile radio telephones 1G: Analog cellular telephony 2G: Digital cellular telephony 3G: High-speed digital cellular telephony (including video telephony) LTE (4G): IP-based anytime, anywhere voice, data, and multimedia telephony at faster data rates than 3G

16 CELLULAR SYSTEMS GENERATIONS 1G (first generation) voice-oriented systems based on analog technology; ex.: Advanced Mobile Phone Systems (AMPS) and cordless systems 2G (second generation) - voice-oriented systems based on digital technology; more efficient and used less spectrum than 1G; ex.: Global System for Mobile (GSM) and US Time Division Multiple Access (US-TDMA) 3G (third generation) high-speed voice-oriented systems integrated with data services; ex.: General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA) 4G (fourth generation) still experimental, not deployed yet; based on Internet protocol networks and will provide voice, data and multimedia service to

17 FREQUENCY REUSE is a method used by service providers to improve the efficiency of a cellular network and to serve millions of subscribers using a limited radio spectrum is based on the fact that after a distance a radio wave gets attenuated and the signal falls bellow a point where it can no longer be used or cause any interference a transmitter transmitting in a specific frequency range will have only a limited coverage area beyond this coverage area, that frequency can be reused by another transmitter

18 NETWORK CELLS the entire network coverage area is divided into cells based on the principle of frequency reuse a cell = basic geographical unit of a cellular network; is the area around an antenna where a specific frequency range is used; is represented graphically as a hexagonal shape, but in reality it is irregular in shape when a subscriber moves to another cell, the antenna of the new cell takes over the signal transmission a cluster is a group of adiacent cells, usually 7 cells; no frequency reuse is done within a cluster the frequency spectrum is divided into subbands and each subband is used within one cell of the cluster in heavy traffic zones cells are smaller, while in

19 NETWORK CELLS (2)

20 TYPES OF CELLS macrocell their coverage is large (aprox. 6 miles in diameter); used in remote areas, high-power transmitters and receivers are used microcell their coverage is small (half a mile in diameter) and are used in urban zones; lowpowered transmitters and receivers are used to avoid interference with cells in another clusters picocell covers areas such as building or a tunnel

21 OTHER CELLULAR CONCEPTS handover = moving a call from one zone (from the transmitter-receiver from one zone) to another zone due to subscriber s mobility roaming = allowing the subscriber to send/receive calls outside the service provider s coverage area

22 MULTIPLE ACCESS SCHEMES Frequency Division Multiple Access - when the subscriber enters another cell a unique frequency is assigned to him; used in analog systems Time Division Multiple Access - each subscriber is assigned a time slot to send/receive a data burst; is used in digital systems Code Division Multiple Access - each subscriber is assigned a code which is used to multiply the signal sent or received by the subscriber

23 THE CONTROL CHANNEL this channel is used by a cellular phone to indicate its presence before a frequency/time slot/code is allocated to him

24 CELLULAR SERVICES voice communication Short Messaging Service (SMS) Multimedia Messaging Service (MMS) Global Positioning System (GPS) Wireless Application Protocol (WAP) to access the Internet

25 SIMPLIFIED VIEW OF 3G 25 NodeB & Base Mobile Station switching Serving GPRS Support Node: Controller: center: Gateway GPRS Support Node: Move IP packets to/from radio Converts RF Analog to wiredto digital Route to/from the Interet network

26 CELLULAR NETWORK COMPONENTS

27 CELLULAR NETWORK COMPONENTS (2) BTS (Base Transceiver Station) main component of a cell and it connects the subscribers to the cellular network; for transmission/reception of information it uses several antennas spread across the cell BSC (Basic Station Controller) it is an interface between BTSs and it is linked to BTSs by cable or microwave links; it routes calls between BTSs; it is also connected to the MSC MSC (Mobile Switching Center) the coordinator of a cellular network, it is connected to several BSCs, it routes calls between BSCs; links the cellular network with other networks like PSTN through fiber optics, microwave or copper cable

28 COMPONENTS OF A CELLULAR PHONE (MSU MOBILE SUBSCRIBER UNIT) radio transceiver low power radio transmitter and receiver antenna, usually located inside the phone control circuitry formats the data sent to and from the BTS; controls signal transmission and reception man-machine interface consists from a keypad and a display; is managed by the control circuitry Subscriber Identity Module (SIM) integrated circuit card that stores the identity information of subscriber battery, usually Li-ion, the power unit of the phone

29 SETTING UP A CALL PROCESS when powered on, the phone does not have a frequency/ time slot/ode assigned to it yet; so it scans for the control channel of the BTS and picks the strongest signal then it sends a message (including its identification number) to the BTS to indicate its presence the BTS sends an acknowledgement message back to the cell phone the phone then registers with the BTS and informs the BTS of its exact location after the phone is registered to the BTS, the BTS assigns a channel to the phone and the phone is ready to receive or make calls

30 MAKING A CALL PROCESS the subscriber dials the receiver s number and sends it to the BTS the BTS sends to its BSC the ID, location and number of the caller and also the number of the receiver the BSC forwards this information to its MSC the MSC routes the call to the receiver s MSC which is then sent to the receiver s BSC and then to its BTS the communication with the receiver s cell phone is established

31 RECEIVING A CALL PROCESS when the receiver phone is in an idle state it listens for the control channel of its BTS if there is an incoming call the BSC and BTS sends a message to the cells in the area where the receiver s phone is located the phone monitors its message and compares the number from the message with its own if the numbers matches the cell phone sends an acknowledgement to the BTS after authentication, the communication is established between the caller and the receiver

32 GLOBAL SYSTEM FOR MOBILE COMMUNICATION (GSM)

33 GSM CHARACTERISTICS previous standard in cellular communication were restrictive GSM global digital standard for cellular phones that offered roaming facility first named Groupe Special Mobile and used in Europe; then usage extended to other continents GSM operate in frequency bands: 900MHz, 1800 MHz, 1900 MHz GSM provides voice and data services

34 SUBSCRIBER IDENTITY MODULE (SIM) CARD SIM a memory card (integrated circuit) holding identity information, phone book etc. GSM system support SIM cards other systems, like CDMA do not support SIM cards, but have something similar called Re-Usable Identification Module (RUIM)

35 INTERNATIONAL MOBILE EQUIPMENT IDENTITY (IMEI) KEY IMEI a unique 15 digit number identifying each phone, is incorporated in the cellular phone by the manufacturer IMEI ex.: when a phone tries to access a network, the service provider verifies its IMEI with a database of stolen phone numbers; if it is found in the database, the service provider denies the connection the IMEI is located on a white sticker/label under the battery, but it can also be displayed by typing *#06# on the phone

36 INTERNATIONAL MOBILE SUBSCRIBER IDENTITY (IMSI) KEY IMSI a 15-digit unique number provided by the service provider and incorporated in the SIM card which identifies the subscriber IMSI enables a service provider to link a phone number with a subscriber first 3 digits of the IMSI are the country code

37 GSM ARCHITECTURE

38 BASE STATION SUBSYSTEM (BSS)

39 HLR, VLR AND EIR REGISTERS Home Location Register (HLR) - is a database maintained by the service provider containing permanent data about each subscriber (i.e. location, activity status, account status, call forwarding preference, caller identification preference) Visitor Location Register (VLR) database that stores temporary data about a subscriber; it is kept in the MSC of the of the area the subscriber is located in; when the subscriber moves to a new area the new MSC requests this VLR from the HLR of the old MSC Equipment Identity Register (EIR) database located near the MSC and containing information identifying cell phones

40 AUTHENTICATION CENTER (AUC) 1 st level security mechanism for a GSM cellular network is a database that stores the list of authorized subscribers of a GSM network it is linked to the MSC and checks the identity of each user trying to connect also provides encryption parameters to secure a call made in the network

41 BIBLIOGRAPHY 1. "The Benefits of Cell Phones." Cell Phone and Wireless Service Plan Buying Guide (2008) 20 Sep "Mobile Phone Exposure Causes Brain Damage in Rats." EHP: Environmental Health Perspectives "Excessive Mobile Phone Use Affects Sleep In teens, Study Finds." Science Daily "Is Txt Mightier Than the Word." BBCNews "7 Disadvantages of Cell Phones." ControlYourImpact

42 QUESTIONS/COMMENTS? 42