Lecture slides, updated 16.04.2009

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  • Allow terminals (e.g., portable computers or PDAs) to create temporary, wireless networks Terminals transmit and receive data over air, using electromagnetic waves. Terminals communicate directly with each other, not via base stations (like in cellular systems)

Transcript

  • 1. OTHER NETWORKS c@Irek Defée MULTIMEDIA SYSTEMS
  • 2. CABLE MODEMS c@Irek Defée MULTIMEDIA SYSTEMS
  • 3.
    • CABLE TV DOES NOT SUFFER FROM
    • THE TELEHONE CABLE PROBLEM
    • TV CABLE IS VERY BROADBAND,
    • BANDWIDTH AT LEAST TO 1 GHz,
    • SIGNAL TRANSMISSION IS
    • EXCELLENT
    • CABLE TV NETWORK ARCHITECTURE IS A PROBLEM
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 4.
    • ALL USERS SHARE THE SAME CABLE
    • CABLE BANDWIDTH IS DIVIDED INTO ’TV’ CHANNELS
    • A TV CHANNEL CAN BE USED AS A DATA CHANNEL USING DIGITAL MODULATION, SUCH CHANNEL CAN
    • CAN HAVE E.G. 50 Mb/s CAPACITY
    • THE MORE USERS WOULD SHARE IT
    • THE LESS BANDWIDTH THEY GET
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 5.
    • SECOND PROBLEM: TV CHANNELS ARE USED FOR RECEIVING SIGNALS
    • HOW USERS CAN SEND THEIR
    • DATA?
    • CABLE NETWORK MUST BE REDESIGNED TO
    • ALLOW DATA SENDING USING CABLE MODEM
    • ALLOW SEPARATE STREAM FOR EACH USER
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 6.
    • STANDARDS WERE DEFINED FOR
    • THIS
    • FOR RECEIVING DATA ANY TV CHANNEL CAN BE ALLOCATED
    • IN THE BAND 70-130 MHz AND
    • 300-862 MHz
    • FOR SENDING DATA THE BAND 5-65 MHz IS ALLOCATED
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 7.
    • SIGNAL MODULATION IN CABLE MODEMS
    • QPSK - QUADRATURE PHASE SHIFT
    • KEYING
    • QAM – QUADRATURE AMPLITUDE
    • MODULATION
    c@Irek Defée MULTIMEDIA SYSTEMS . PHASE OF THE SIGNAL IS CHANGED (HERE FOUR VALUES ARE USED) 00 01 11 10
  • 8.
    • PHASE AND AMPLITUDE CAN BE
    • CHANGED – QAM
    c@Irek Defée MULTIMEDIA SYSTEMS HERE WE CAN ASSIGN 3 BITS TO EACH VALUE OF AMPLITUDE AND PHASE 000 THE MORE AMPLITUDE AND PHASE VALUES THE MORE INFORMATION CAN BE SEND, BUT SIGNAL IS MORE SENSITIVE TO NOISE
  • 9. c@Irek Defée MULTIMEDIA SYSTEMS 16-QAM BIT ASSIGNMENT
  • 10.
    • FOR THE UPSTREAM CHANNEL
    • (FROM THE USER) 0.2, 1 OR 2 MHz
    • CHANNELS CAN BE USED, THEY
    • ARE QPSK MODULATED. DATA RATE
    • IS 256 kb/s, 1.5 Mb/s, 3 Mb/s, 6 Mb/s
    • FOR THE DOWNSTREAM CHANNEL
    • THE TV CHANNEL IS USED. 64 OR
    • 256 QAM MODULATION, DATA RATE
    • 30-50 Mb/s
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 11.
    • A SIMPLE SYSTEM IS THE ONE IN WHICH ALL USERS SHARE THE SAME
    • CHANNEL, IT IS LIKE THE ETHERNET
    • BANDWIDTH DEPENDS ON THE NUMBER OF USERS AND NETWORK
    • LOAD.
    • THIS SYSTEM IS A KIND OF LAN AND
    • IS RELATIVELY VERY CHEAP FOR
    • ITS BANDWIDTH
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 12.
    • MORE COMPLICATED SYSTEM IS THE ONE IN WHICH USERS GET THEIR OWN STREAMS
    • HOW THIS CAN BE DONE?
    • - EACH 40 Mb/s CHANNEL IS ENOUGH
    • FOR 8-10 USERS
    • - MORE TV CHANNELS CAN BE
    • ALLOCATED TO DATA TRANSMISSION
    • FOR EXAMPLE WITH 20 CHANNELS ONE CAN GET 200 USERS
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 13.
    • CABLE TV NETWORK CAN BE
    • SPLIT AROUND HEADEND
    • AMPLIFIERS
    c@Irek Defée MULTIMEDIA SYSTEMS USERS (100-200 PER HEADEND) DISTRIBUTION (FIBER OPTICS)
  • 14.
    • THUS FROM EACH CABLE HEADEND
    • USERS CAN BE SUPPLIED BY THEIR
    • OWN STREAMS
    • CABLE TV NETWORK IS THUS ABLE
    • TO SUPPLY VERY MANY USERS WITH
    • HIGH BANDWIDTH NETWORKING SERVICE
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 15. WIRLESS SYSTEMS CELLULAR NETWORKS c@Irek Defée MULTIMEDIA SYSTEMS
  • 16. c@Irek Defée MULTIMEDIA SYSTEMS
    • THERE ARE SEVERAL METHODS FOR EFFICIENT
    • MANAGEMENT OF RADIO TRANSMISSION:
    • FDM, FREQUENCY DIVISION MULTIPLEX
    • TRANSMITTERS USE DIFFERENT FREQUENCY
    • BANDS (example: television, radio)
    • TDM, TIME DIVISION MULTIPLEX,
    • TRNSMITTERS ARE USED AT DIFFERENT TIMES
    • SDM, SPATIAL DIVISION MULTIPLEX, TRNSMITTERS
    • OPERATE IN SEPARATED AREAS (mobile phones)
    • CDM, CODE DIVISION MULTIPLEX, TRANSMITTERS
    • OPERATE WITH DIFFERENT ACCESS CODES
    • WHICH MINIMIZE INTERFERENCE (mobile phones)
    • If we have transmitters and receivers we can talk about Access
    • to the reception and systems are called CDMA, FDMA,...
  • 17. c@Irek Defée MULTIMEDIA SYSTEMS
    • THESE ACCESS SYSTEMS CAN BE USED IN ALL KIND
    • OF COMBINATIONS, TDMA/FDMA/SDMA ETC.
    • SYSTEMS CAN BE DESIGNED FOR OPTIMAL USE OF
    • RADIO WAVES WITH THOSE ACCESS SYSTEMS:
    • SDMA – IS A BASIS FOR CELLULAR SYSTEMS ,
    • FREQUENCIES CAN BE REUSED IN
    • SEPARATED CELLS
    THERE IS A TRANSMITTER IN THE CENTER OF EACH CELL
  • 18.
    • THE COST OF THIS IS THAT ONE NEEDS TO IMPLEMENT HANDOVER WHEN MOVING BETWEEN THE CELLS AND ALSO TRACK THE LOCATION USERS
    • WITHIN THE CELLS TDMA/FDMA, CDMA CAN BE REUSED IN DIFFERENT COMBINATIONS
    • EXAMPLE: THE GSM SYSTEM: OPERATES IN TWO BANDS
    • 900 AND 1800 MHz, WIDTH 25 AND 75 MHz,
    • WIDTH OF ONE CHANNEL – 200 kHz FDMA
    • CHANNEL DIVIDED INTO 8 time slots - TDMA
    • WHY? IT SAVES THE NUMBER OF TRANSMITTERS
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 19. c@Irek Defée MULTIMEDIA SYSTEMS
    • - IN ADDITION GSM THE SYSTEM HAS ALSO
    • A KIND OF CDMA – FREQUENCY HOPPING:
    • FREQUENCY BAND CAN BE CHANGED FROM
    • TIME SLOT TO TIME SLOT ACCORDING TO
    • SPECIFIC PATTERN. THIS LEADS TO
    • STATISTICALLY BETTER USE.
    • HOW MANY USERS CAN BE SUPPORTED?
    • IF ONE BASE STATION TAKES 5 MHz IT
    • CAN SUPPORT 200 USERS (175). MINIMUM
    • CELL SIZE IS 100-500M(?). SO WE CAN GET
    • HIGH DENSITY OF USERS/km 2
  • 20.
    • THE GSM WIRELESS CELLULAR
    • SYSTEM STARTED AS FOR TELEPHONE APPLICATIONS
    • THIS SYSTEM IS QUICKLY
    • EVOLVING AND WILL CONTINUE TO
    • DO SO IN THE FUTURE DATA
    • TRANSMISSION AND MULTIMEDIA WILL
    • BE MOST IMPORTANT
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 21.
    • GSM UPGRADES
    • - GPRS – PACKET SWITCHING,
    • CONNECTIONLESS SERVICE
    • - HSCSD – HIGH SPEED CIRCUIT
    • SWITCHED DATA
    • - EDGE – BANDWIDTH INCREASE WITH NEW MODULATION BASED ON 8-PSK
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 22. c@Irek Defée MULTIMEDIA SYSTEMS 144 kbps 144 kbps ISDN Standards Implementation 2048 kbps 384 kbps WCDMA Maximum Data Rate for New Systems 470 kbps < 470 kbps EDGE 171 kbps 57.6 kbps GPRS 57.6 kbps 28.8 kbps HSCSD 9.6 kbps 9.6 kbps GSM Data
  • 23.
    • 1. GPRS
    • - PACKET SWITCHING RUNNING IN
    • FREE CAPACITY OF GSM SLOTS
    • - VERY FLEXIBLE
    • - SEVERAL CODING SCHEMES
    • - FLEXIBLE USE OF TIME SLOTS
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 24. GPRS PACKETS ALLOCATION
    • Radio resources allocation
      • either to Circuit Switched service
      • or to Packet Switched service
    • Priority can be given to one service while ensuring minimum capacity for the other one
    c@Irek Defée MULTIMEDIA SYSTEMS TDMA frame TRX : GPRS & GSM 0 7 TS number GPRS only GSM only GSM or GPRS
  • 25. Coding schemes in GPRS
    • 4 coding schemes for packet transfers
    c@Irek Defée MULTIMEDIA SYSTEMS
      • thus data rates increase
    CS information protection data rates (Kbits/s) CS4 : no protection 21.4 CS1 : same as GSM measurements reporting 13.4 15.6 9. 05 CS2 CS3
  • 26. GPRS coverage
    • New design thresholds
      • depending on coding scheme
      • due to decreasing protection / interferences
    • On existing networks
      • &quot;concentric&quot; GPRS coverage
    c@Irek Defée MULTIMEDIA SYSTEMS GSM only cell enabling GPRS GSM coverage CS1 CS2 CS3 CS4
  • 27. c@Irek Defée MULTIMEDIA SYSTEMS Coverage of GPRS GSM Voice (1) CS1 (1.06) CS2 (0.82) CS3 (0.72) CS4 (0.42) Base Station There is no significant change in coverage from GSM to GPRS CS1 and CS2 Cell Radius
  • 28. Traffic management
    • GSM & GPRS cell :
      • allocation of radio resources (time slots) to the services
      • then allocation of GPRS resources to the users
    • Radio resources management efficiency depends on :
      • target for qualities of service
      • operator strategy and parameters set
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 29. c@Irek Defée MULTIMEDIA SYSTEMS BTS MSC/ VLR SGSN GGSN BSC PCU GMSC GPRS Backbone IP Network BG CG DNS BG = Border Gateway CG = Charging Gateway DNS = Domain Name Systems PCU = Packet Control Unit SGSN = Serving GPRS Support Node GGSN = Gateway GPRS Support Node BTS = Base Transceiver Station BSC = Base Station Controller MSC = Mobile Services Switching Centre GMSC = Gateway MSC HLR New GPRS Network Elements Existing Elements New Elements
  • 30. c@Irek Defée MULTIMEDIA SYSTEMS Application IP / X.25 SNDCP LLC RLC MAC GSM PL SNDCP BSSGP L1bis RLC MAC GSM PL LLC Relay L2 L1 L2 L1 IP GTP IP / X.25 Um Gb Gn Gi MS BSS SGSN GGSN Frame Relay Frame Relay BSSGP L1bis LLC GTP IP In order to reach their final destination, data coming from external network are tunnelled twice: into GTP packets in the Core Network and into LLC frames (SNDCP allows multi-protocol) in the Access Network. THE GPRS TRANSPORT PLANE TLLI TID IP
  • 31. c@Irek Defée MULTIMEDIA SYSTEMS X25 end to end GGSN SGSN GPRS IP backbone GTP tunnel layer LLC tunnel layer IP end to end RADIO specific L2 One of the requirements in the original GPRS design was providing a system being able to support in the same way IP and X25 data. Consequently GPRS backbone was not fully optimized for IP data and a general purpose tunneling protocol was designed for this. As a result the GPRS transport plane is characterized by an heavy 3 layer protocol stack. (e.g. the use of IP over TCP over GTP over TCP over IP is allowed in the GPRS backbone) 3 layer stack THE THREE LAYER TRANSPORT PLANE IN GPRS BACKBONE
  • 32.
    • HSCSD
    • - CIRCUIT SWITCHING BY RESERVATION OF SEVERAL TIME
    • SLOTS (UP TO 4) IN GSM
    • - IT IS SIMPLE AND PROVIDES MUCH
    • MORE BANDWIDTH BUT IT TAKES
    • TIME FOR CONNECTION
    • - HOW HSCSD COMPARE FOR
    • DATA RATES?
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 33. c@Irek Defée MULTIMEDIA SYSTEMS
      • HSCSD User Data Rate
      • transparent service non transparent service
      • GPRS User Data Rate
  • 34. c@Irek Defée MULTIMEDIA SYSTEMS GSM Wireless Data Development Steps 3Q 1999 3Q 2000 High Speed Data Circuits HSCSD n*14.4 (3*14.4 = 43.2) High Speed Packet Capabilities GPRS (e.g. 3* 13.4 = 40.2)
  • 35. c@Irek Defée MULTIMEDIA SYSTEMS High Speed data circuits HSCSD n*14.4 (3*14.4 = 43.2) MSC BSC BTS BTS UDI ISDN GSM IWE PSTN Internet Corporate Networks LAN
  • 36.
    • HSCSD is available and offers four times higher bandwidth than the today‘s GSM data service thus being very well compatible to the standard fix network connection.
    • HSCSD requires minor network upgrades only. No new network elements are required at all. The invest is about a fifth of the one for GPRS.
    • HSCSD charging principles are well introduced in the network and well accepted by the customers.
    • HSCSD has a well defined QoS and can thus be used to address the high expectation market segment.
    c@Irek Defée MULTIMEDIA SYSTEMS HSCSD: Pros and Cons
    • HSCSD is still circuit switched, i.e. the network load is not as efficiently handled as with GPRS and thus an always on service is hard to deliver.
    • HSCSD is not the service to address the mass market with.
  • 37. c@Irek Defée MULTIMEDIA SYSTEMS MSC BSS GSM HLR High Speed Packet Capabilities GPRS (e.g. 3* 13.4 = 40.2) BTS GPRS backbone FR / ATM GGSN GGSN GGSN SGSN Border GW Corporate Networks other PLMN Internet
  • 38. c@Irek Defée MULTIMEDIA SYSTEMS
    • GPRS offers up from mid 2000 a four times higher bandwidth than the today‘s GSM data service.
    • GPRS offers optimal network resource usage and optimized mobile Internet access by introducing the packet switched principle into GSM.
    • GPRS allows to address the mass market with an always on data service.
    GPRS: Pros and Cons
    • Due to the IP character the GPRS QoS can not be guaranteed.
    • GPRS requires major network upgrades and totally new network elements. GPRS is expensive.
    • Charging principles of GPRS are unclear and thus appropriate interfaces to the billing systems do not exist.
  • 39. c@Irek Defée MULTIMEDIA SYSTEMS New Mobile Applications
  • 40. c@Irek Defée MULTIMEDIA SYSTEMS Smart Messaging Banking Traffic info & guidance News Weather Ticket ordering Info- & Entertainment- Services Fleet management GPRS Internet Intranet E-mail Scheduler Access Remote control Monitoring HTTP / HTML HSCSD File transfer Corporate access / tele working Online e-mail Real-time applications E-cash & payments Audio & video on demand Video surveillance services (e.g. taxi, money transport) Remote healthcare WAP / WML
  • 41.
    • Intranet access
    • Tele working
    • Online e-mail / fax
    • Websurfing
    • Electronic payment services
    • Mobile banking
    c@Irek Defée MULTIMEDIA SYSTEMS APPLICATION AREAS Business Private With focus on
    • Reliability
    • Sufficient data rates
    • Ease of Use
    With focus on
    • Price
    • Price
    • Price
    Best addressed by HSCSD Best addressed by GPRS
  • 42.
    • THIRD GENERATION CELLULAR SYSTEMS
    • THESE SYSTEMS ARE BEING
    • DESIGNED FROM GROUND UP FOR
    • MULTIMEDIA APPLICATIONS:
    • HIGH BANDWIDTH STREAMING
    • SERVICES
    • PACKET BASED APPLICATIONS
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 43.
    • SIGNAL MODULATION TECHNOLOGY
    • IS WIDEBAND W CDMA,WHY?
    • SPECIFIC PROBLEM IN MOBILE
    • STREAMING IS CELL SWITCHING, OR
    • HANDOVER. HANDOVER IS CRITICAL
    • BECAUSE DATA MIGHT BE LOST.
    • IN CDMA ”SOFT” HANDOVER IS
    • POSSIBLE BECAUSE BANDS
    • CAN BE SHARED BY BASE STATIONS
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 44. c@Irek Defée MULTIMEDIA SYSTEMS
    • What is UMTS? Called popularly 3G
      • Universal Mobile Telecommunications Service
      • Member of IMT-2000 family
      • Global multimedia
      • Replacement (complement) for GSM
  • 45. c@Irek Defée MULTIMEDIA SYSTEMS
    • Spectrum allocation for UMTS
      • 2x60MHz paired spectrum + 20 MHz and 15 MHz unpaired = 155 MHz
  • 46. c@Irek Defée MULTIMEDIA SYSTEMS UTRA Key Parameters UTRA – UMTS TERRESTRIAL RADIO ACCESS FDD TDD Multiple access scheme W-CDMA TD-CDMA Carrier spacing 4·4 – 5·2 MHz 5 MHz Chip rate 3·84 Mchip/s (Mcps) Spreading factor range 4–512 1–16 Modulation QPSK Pulse shaping root raised cosine, roll-off = 0·22 Frame length 10 ms Timeslots per frame 15
  • 47. Enhancements to 3G data capacity
    • The data rate of basic 3G network is in the
    • range of 128-384 kb/s which is not much for current demands
    • Upgrades were developed for significant increasing of the data rate. They are called in general
    • HSPA – High Speed Packet Access, two methods used are:
    • HSDPA - High Speed Downlink Packet Access
    • HSUPA – High Speed Uplink Packet Access
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 48. HSDPA
    • High Speed Download Packet Access
    • Information is sent to the users
    • HSDPA uses QPSK and 16-QAM modulation.
    • Users share data channel in 2 ms time frames
    • (several users may be served in one frame)
    • The data rate speed will depend on the type
    • of modulation, the number of users and priorities.
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 49. HSDPA data rates c@Irek Defée MULTIMEDIA SYSTEMS The maximum data rate is theoretical peak rate for single user, effective data rate is in the range 1-2 Mb/s Category Max. number of HS-DSCH codes Modulation Max. data rate [Mbit/s] 1 5 QPSK and 16-QAM 1.2 2 5 QPSK and 16-QAM 1.2 3 5 QPSK and 16-QAM 1.8 4 5 QPSK and 16-QAM 1.8 5 5 QPSK and 16-QAM 3.6 6 5 QPSK and 16-QAM 3.6 7 10 QPSK and 16-QAM 7.3 8 10 QPSK and 16-QAM 7.3 9 15 QPSK and 16-QAM 10.2 10 15 QPSK and 16-QAM 14.4 11 5 QPSK only 0.9 12 5 QPSK only 1.8
  • 50. HSUPA
    • High Speed Uplink Packet Access
    • Information is sent from the users
    • HSUPA is similar to HSDPA, speed lower
    • HSUPA Category Max Uplink Speed
    c@Irek Defée MULTIMEDIA SYSTEMS Category 1 0.73 Mbit/s Category 2 1.46 Mbit/s Category 3 1.46 Mbit/s Category 4 2.93 Mbit/s Category 5 2.00 Mbit/s Category 6 5.76 Mbit/s Category 7 (3GPP Rel7) 11.5 Mbit/s
  • 51. PERSONAL WIRELESS (Ad-Hoc) NETWORKS c@Irek Defée MULTIMEDIA SYSTEMS
  • 52. Mobile Ad-Hoc Networks
    • Temporary, wireless networks
    • Direct peer-to-peer connection (no base stations)
    • Connection created automatically when devices come close to each other
      • No a priori knowledge of other devices
      • No administration
      • No preconfiguration
    • Data transmitted over air using electromagnetic waves
      • Data is superimposed to a carrier signal
      • Once superimposed, signal occupies a frequency band instead of a single frequency
      • When there are many radio signals in the same space, the signals have to be separated somehow.
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 53. Signal Separation
    • Narrowband technologies
      • one transmitter uses one frequency
      • receiver tunes into correct frequency
    • Wideband technologies
      • more advanced
      • use spread spectrum technology
    • There are two common types of spread spectrum technologies
      • FHSS : Frequency Hopping Spread Spectrum
      • DSSS : Direct Sequence Spread Spectrum
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 54. Frequency Hopping Spread Spectrum
    • FHSS uses narrowband carrier
      • Carrier changes frequency between time slices
    • The receiver must know the pattern according to which the frequency is changing
    • To an unintended receiver the signal appears to be short duration impulse noise
    c@Irek Defée MULTIMEDIA SYSTEMS 1 2 3 4 5 F r e q u e n c y 80 60 40 20 10 Time
  • 55. Direct Sequence Spread Spectrum
    • DSSS generates a redundant bit pattern for each bit to be transmitted
    • The longer the pattern,
      • the greater the probability that the original signal can be recovered
      • the more bandwidth is required
    • To and unintended receiver DSSS appears as low-power wideband noise
    c@Irek Defée MULTIMEDIA SYSTEMS One Zero
  • 56. RF Ad-Hoc Network Characteristics
    • Easy to install & configure compared to wired networks
    • Freedom to move the transmitter and receiver
    • Carrier signal typically 2.4 GHz (or 5 GHz)
    • Transmitter coverage typically 10 ... 100 m
      • Depends on transmitter power, receiver design and propagation path
    • Data rates 1 ...10 Mbps
      • Depends on number of users in the same space, interference from other sources and propagation factors
    • Security is provided with data encryption
      • Eavesdropping easier than in wired networks
    • Battery life limits use
    • Safety of radio waves
      • Transmitter power is small compared to cellular phones
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 57. Bluetooth
    • A specification for short-range RF communication
      • communication between portable devices
      • communication between computer and peripherals
    • Bluetooth chip characteristics:
      • small size
      • low power consumption
    • Developed in 1994 by Ericsson
    • 1997: Bluetooth SIG (Special Interest Group)
      • Original SIG: Ericsson, Nokia, IBM, Toshiba, Intel
      • Currently over 1600 members in the SIG
    • Before manufacturers can market their device as Bluetooth device, it must be approved by the SIG.
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 58. Who Is Bluetooth?
    • Harald Blaatand “Bluetooth” II, King of Denmark 940-981
      • Son of Gorm the Old (King of Denmark) and Thyra Danebod (daughter of King Ethelred of England)
    • This is one of two Runic stones erected in his capitol city of Jelling (central Jutland)
      • This is the front of the stone depicting the chivalry of Harald
      • The stone’s inscription (“runes”) say:
        • Harald christianized the Danes
        • Harald controlled Denmark and Norway
        • Harald thinks notebooks and cellular phones should seamlessly communicate
  • 59. What Does Bluetooth Do? Personal Ad Hoc Networks Cable Replacement Landline Data/Voice Access Points
  • 60. Bluetooth - Technology
    • Operates on 2,4 GHz ISM band
      • also microwave ovens, WLAN systems, baby monitors, garage door openers and cordless phones use this band
    • Normal coverage 10 m (1mW)
      • also 100 m possible (but conflicts with Bluetooth principle)
    • Uses FHSS
      • band 2,400 ... 2,500 GHz is divided into 79 subbands (1MHz each) (in some countries only 23 subbands)
      • transmission further divided into time slots (625  s)
      • clocks synchronised to master’s clock
      • 1 packet/slot, after that changes to new frequency
      • 1600 hops/sec
        • fast hopping, short packets  more reliable transmission (re-sending of one corrupted packet is not a demanding task)
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 61. Radio Protocol
    • Spread spectrum frequency hopping radio
      • 79/23 one MHz channels
      • Hops every packet
        • Packets are 1, 3 or 5 slots long
      • Frame consists of two packets
        • Transmit followed by receive
      • Nominally hops at 1600 times a second (one slot packets)
  • 62. Bluetooth - Data and Voice
    • Data & voice set different requirements for transmission
    • Data: speed & reliability (even one bit can’t change)
    • Voice: stream of packets must not be interrupted
      • speed & reliability not so important
    • To fulfill both requirements, Bluetooth uses ideas of both packet and circuit switched connection
    • Voice: SCO (Synchronous Connection Oriented)
      • time slots are reserved for the stream (  steady stream)
      • possible because only one device can transmit at a time & master can reserve time slots (max speed 64 kbps)
    • Data: ACL (Asynchronous Connectionless)
      • can be symmetric or asymmetric (432,6 kbps ; 721 kbps / 57,6 kbps respectively)
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 63. Bluetooth - Piconets and Scatternets
    • Bluetooth supports point-to-point and point-to-multipoint data and voice communication
    • Communicating devices (max 8) form a PICONET
    • Master can be any of the devices
      • clock, frequency hopping pattern
    • Devices can freely join and leave a piconet
    • Each device can simultaneously belong to several piconets
    • Combination of several piconets = SCATTERNET
      • each piconet has its own master & hopping pattern
      • piconets in a scatternet are not synchronized  collisions are rare, piconets can maintain good performance
    • Piconets are small (not meant to replace WLAN)
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 64. The Piconet
    • All devices in a piconet hop together
      • In forming a piconet, master gives slaves its clock and device ID
        • Hopping pattern determined by device ID (48-bit)
        • Phase in hopping pattern determined by Clock
    • Non-piconet devices are in standby
    • Piconet Addressing
      • Active Member Address (AMA, 3-bits)
      • Parked Member Address (PMA, 8-bits)
    or
  • 65. Network Topology
    • Radio Designation
      • Connected radios can be master or slave
      • Radios are symmetric (same radio can be master or slave)
    • Piconet
      • Master can connect to seven simultaneous or 200+ active slaves per piconet
      • Each piconet has maximum capacity (1 MSPS)
        • Unique hopping pattern/ID
    • Scatternet
      • High capacity system
        • Minimal impact with up to 10 piconets within range
      • Radios can share piconets!
  • 66. Bluetooth Baseband Protocol
    • There are altogether 7 states a Bluetooth device can have:
    • Standby: Waiting to join a piconet
    • I n quire: Ask about radios to connect to
    • Page: Connect to a specific radio
    • Connected: Actively on a piconet (master or slave)
    • PARK / HOLD: Low power connected states
    • In hold/park state modes the device consumes only 60 microAmperes. In active data mode 5mA and in active voice mode 8-30 mA.
    • The device can start participating from park/hold modes within 2 ms.
    • There can be more than 200 devices that are in park/hold modes connected to master.
    c@Irek Defée MULTIMEDIA SYSTEMS Standby Inquiry Page Transmit Connected Park Hold
  • 67. Functional Overview
    • Standby
      • Waiting to join a piconet
    • Inquire
      • Ask about radios to connect to
    • Page
      • Connect to a specific radio
    • Connected
      • Actively on a piconet (master or slave)
    • Park/Hold
      • Low Power connected states
    Inquiry Page Connected AMA Transmit data AMA T typical=0.6s T typical=2s HOLD AMA PARK PMA T typical=2 ms T typical=2 ms Releases AMA Address Low Power States Active States Standby Connecting States Unconnected Standby Detach
  • 68. Bluetooth Architecture
    • Protocol stack, which includes plenty of protocols, e.g., RFCOMM (Radio Frequency COM port), SDP (Service Discovery Protocol), TCP/IP and WAP.
    • The applications sit on top of the protocol stack.
    • RF: Radio transmitter/receiver, frequency hopping
    • BASEBAND: Piconet and channel definition, low-level packet definition
    • LINK MANAGER: Defines encryption, authentication, SCO mode, low-power mode
    • L2CAP: Link Layer Control And Adaptation defines a simple data link protocol on top of baseband
    • CONTROL: Host Controller Interface provides a common interface between the Bluetooth host and a Bluetooth module (e.g., USB, UART, RS232).
    c@Irek Defée MULTIMEDIA SYSTEMS RF Baseband Link Manager L2CAP Audio TCP / IP, WAP,SDP, RFCOMM etc. C O N T R O L Applications
  • 69. What Is Bluetooth?
    • A hardware description
    • An application framework
    Application Framework and Support Link Manager and L2CAP Radio & Baseband Host Controller Interface RF Baseband Audio Link Manager LMP L2CAP TCP/IP HID RFCOMM Applications Data Control
  • 70. Bluetooth - Error Correction
    • Bluetooth uses three different error correction schemes: FEC, ARQ and CSVD
    • FEC (Forward Error Correction Code)
      • corrects the errors
      • purpose: reduce number of retransmissions
      • always used for packet headers
      • is effective, but in good conditions adds unnecessary overhead to packets
    • ARQ (Automatic Repeat Request)
      • If checksum of bits does not match, packet is retransmitted
      • Good in good conditions : seldom need for retransmitting
    • CSVD (Continuous Variable Slope Delta Modulation)
      • used when transmitting sound, because retransmitting of packets is not sensible
      • With help of CSVD speech is understandable even if 4% of packets are corrupted
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 71. Bluetooth - Security
    • Bluetooth hardware supports
      • user authentication (one-way / two-way / no authentication)
      • data encryption (secret key length 0 ; 40 or 64 bits)
      • session key generation
    • Three entities are used in the security algorithms:
      • Bluetooth unit address (public entity)
      • Private user key (secret entity)
      • Random number (different for each new transaction)
    • Users who need stronger protection can use upper layers of Bluetooth stack to do this (network transport protocol / application programs)
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 72. Bluetooth - Software
    • Piconets are controlled by software
    • Software can reside in any of the participating devices
    • Lot of software is needed to build sensible applications
    • Applications can use existing protocols like TCP/IP, WAP, RFCOMM, OBEX ...
    • E.g. Java-based JINI architecture by Sun Microsystems can handle the communication between participants in an ad-hoc network.
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 73. BLUETOOTH APPLICATIONS
    • PARK RIDGE, Ill. — Motorola Inc. will take Bluetooth a step closer to the automobile this week, as it demonstrates a new in-car communication system at the Convergence 2000 show in Detroit.
    • The demonstration, which involves moving data back and forth from consumer devices to automotive network buses, is believed to be the first of its kind in the automotive industry. It's also one that has been anxiously awaited by automotive engineers, many of whom foresee a vast array of potential applications for Bluetooth's wireless techniques.
    c@Irek Defée MULTIMEDIA SYSTEMS
  • 74. BLUETOOTH APPLICATIONS c@Irek Defée MULTIMEDIA SYSTEMS
  • 75. BLUETOOTH APPLICATIONS c@Irek Defée MULTIMEDIA SYSTEMS
  • 76. BLUETOOTH APPLICATIONS c@Irek Defée MULTIMEDIA SYSTEMS
  • 77. BLUETOOTH APPLICATIONS c@Irek Defée MULTIMEDIA SYSTEMS PAYING FOR TICKETS AND ACCESS IN TRAIN STATION
  • 78. BLUETOOTH APPLICATIONS c@Irek Defée MULTIMEDIA SYSTEMS
  • 79. c@Irek Defée MULTIMEDIA SYSTEMS Conclusions for this lecture:
    • THERE IS VERY WIDE RANGE OF
    • WIRELESS NETWORK SYSTEMS
    • SOME OF THEM WILL HAVE HIGH
    • BANDWIDTH, ALL WILL PROVIDE
    • MULTIMEDIA CAPABILTIES
    • TERMINALS WILL BECOME
    • MULTIMODAL AND MULTISYSTEM
    • GPRS+HSCSD+ EDGE + 3G UMTS + HSD
    • +WLAN+WiMAX + digital TV BROADCAST
    • + BLUETOOTH….