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					               OTHER NETWORKS




c@Irek Defée       MULTIMEDIA SYSTEMS
               CABLE MODEMS




c@Irek Defée      MULTIMEDIA SYSTEMS
•      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
• 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
• 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
• 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
• SIGNAL MODULATION IN CABLE
  MODEMS
 QPSK - QUADRATURE PHASE SHIFT
        KEYING
 QAM – QUADRATURE AMPLITUDE
        MODULATION
               10
                 .            PHASE OF THE SIGNAL
         11          00
                              IS CHANGED (HERE FOUR
                              VALUES ARE USED)
               01

c@Irek Defée              MULTIMEDIA SYSTEMS
• PHASE AND AMPLITUDE CAN BE
  CHANGED – QAM

                           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

c@Irek Defée   MULTIMEDIA SYSTEMS
               16-QAM BIT ASSIGNMENT




c@Irek Defée        MULTIMEDIA SYSTEMS
• 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
• 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
• 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
• CABLE TV NETWORK CAN BE
  SPLIT AROUND HEADEND
  AMPLIFIERS
        DISTRIBUTION (FIBER OPTICS)




                USERS (100-200 PER HEADEND)

c@Irek Defée        MULTIMEDIA SYSTEMS
• 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
               WIRLESS SYSTEMS

        CELLULAR NETWORKS




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,...

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:

1. SDMA – IS A BASIS FOR CELLULAR SYSTEMS,
          FREQUENCIES CAN BE REUSED IN
          SEPARATED CELLS
                               THERE IS A
                               TRANSMITTER
                               IN THE CENTER
                               OF EACH CELL


c@Irek Defée    MULTIMEDIA SYSTEMS
• 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
- 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/km2


c@Irek Defée   MULTIMEDIA SYSTEMS
 •       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
•     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
Maximum Data Rate for New Systems




                Standards                 Implementation

 GSM Data         9.6 kbps                    9.6 kbps

  HSCSD           57.6 kbps                   28.8 kbps

  GPRS            171 kbps                    57.6 kbps

  EDGE            470 kbps                   < 470 kbps

  WCDMA           2048 kbps                   384 kbps

   ISDN           144 kbps                    144 kbps




 c@Irek Defée        MULTIMEDIA SYSTEMS
•     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
GPRS PACKETS ALLOCATION
   Radio resources allocation
        – either to Circuit Switched service
        – or to Packet Switched service

                                            TDMA frame

               TRX : GPRS & GSM
                          TS number    0                    7
               GSM only      GPRS only        GSM or GPRS

   Priority can be given to one service while
   ensuring minimum capacity for the other one
c@Irek Defée                  MULTIMEDIA SYSTEMS
           Coding schemes in GPRS
• 4 coding schemes for packet transfers
                       information         data rates (Kbits/s)
                       protection


  thus data rates
 increase                                         15.6
                                           13.4
                                                         CS4 : no protection
                                                                21.4
                              9. 05
                                                            CS
                                          CS2 CS3
                 CS1 : same as GSM
                 measurements reporting

  c@Irek Defée                MULTIMEDIA SYSTEMS
                GPRS coverage
• New design thresholds
  – depending on coding scheme
  – due to decreasing protection / interferences
• On existing networks
  – "concentric" GPRS coverage
                                                      CS3
                                             CS4
                                                       CS2
                                                        CS1
                       enabling
      GSM only cell                          GSM
                        GPRS
                                           coverage

 c@Irek Defée         MULTIMEDIA SYSTEMS
Coverage of GPRS


                                                           Cell Radius
Base Station
                                                           CS1 (1.06)
                                                           GSM Voice (1)
                                                           CS2 (0.82)
                                                           CS3 (0.72)
                                                           CS4 (0.42)




There is no significant change in coverage from GSM to GPRS CS1 and CS2


   c@Irek Defée           MULTIMEDIA SYSTEMS
               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
 New GPRS Network Elements

                           MSC/
  BTS          BSC                     GMSC
                           VLR
                                                                Existing Elements
                            HLR


                                       GPRS Backbone
               PCU         SGSN          IP Network      GGSN

                                                                 New Elements
BG = Border Gateway
CG = Charging Gateway
DNS = Domain Name Systems              BG     CG   DNS
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




    c@Irek Defée                      MULTIMEDIA SYSTEMS
                    THE GPRS TRANSPORT PLANE

     Application


                                                                                    IP
      IP / X.25                                                        IP / X.25

                                                                 TID
      SNDCP                                     SNDCP    GTP             GTP
                            TLLI
        LLC                                      LLC        IP            IP
                          LLC Relay
        RLC              RLC     BSSGP          BSSGP
                                 Frame          Frame       L2            L2
        MAC              MAC     Relay          Relay
      GSM PL            GSM PL     L1bis         L1bis      L1            L1
                   Um                      Gb                    Gn                Gi
        MS                     BSS                   SGSN               GGSN


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.


    c@Irek Defée                      MULTIMEDIA SYSTEMS
          THE THREE LAYER TRANSPORT PLANE
                 IN GPRS BACKBONE
                                 X25 end to end
                               IP end to end
    LLC tunnel layer           GTP tunnel layer
                                                               L2
    RADIO specific           GPRS IP backbone

                                 3 layer
                                 stack
                        SGSN                   GGSN


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)

   c@Irek Defée                MULTIMEDIA SYSTEMS
•      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
                                HSCSD User Data Rate
                          transparent service            non transparent service
       up- / downlink 100% coverage 95% coverage 100% coverage 95% coverage
            1+1            9.6          14.4          9.6          13.2
            2+2           19.2          28.8         19.2          26.4
            1+3            ---           ----        28.8          39.6
            1+4            ---           ----        38.4          53.8




                                  GPRS User Data Rate
 Coding # of timeslots
 Scheme       1           2         3            4       5         6          7       8
  CS-1     9,05          18,1     27,15         36,2   45,25     54,3       63,35   72,4
  CS-2     13,4          26,8     40,2          53,6     67      80,4       93,8    107,2
  CS-3     15,6          31,2     46,8          62,4     78      93,6       109,2   124,8
  CS-4     21,4          42,8     64,2          85,6    107      128,4      149,8   171,2




c@Irek Defée                      MULTIMEDIA SYSTEMS
                   GSM Wireless Data Development Steps




                                         High Speed Data Circuits
3Q 1999                                  HSCSD n*14.4 (3*14.4 = 43.2)




              High Speed Packet Capabilities
3Q 2000       GPRS (e.g. 3* 13.4 = 40.2)



    c@Irek Defée                MULTIMEDIA SYSTEMS
High Speed data circuits
HSCSD n*14.4 (3*14.4 = 43.2)

                                                               Corporate
                                                               Networks
                                       GSM                                 LAN
                                BTS


                                      BSC   MSC IWE


                               BTS
                                                               ISDN
                                                       UDI




                                                             PSTN


                                            Internet




    c@Irek Defée               MULTIMEDIA SYSTEMS
                       HSCSD: Pros and Cons
  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.

 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.


c@Irek Defée                MULTIMEDIA SYSTEMS
High Speed Packet Capabilities
GPRS (e.g. 3* 13.4 = 40.2)

                                 GSM
                       BTS

                                              HLR               other
                                                                PLMN
                             BSS        MSC




                                                    Border GW
                                         SGSN




                         GGSN      GPRS backbone
                                     FR / ATM
         Corporate                                     GGSN        Internet
         Networks
                                 GGSN



     c@Irek Defée                MULTIMEDIA SYSTEMS
                   GPRS: Pros and Cons
 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.
 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.




c@Irek Defée           MULTIMEDIA SYSTEMS
New Mobile Applications




c@Irek Defée   MULTIMEDIA SYSTEMS
            Smart                     HSCSD                             GPRS
            Messaging

            Banking                   File transfer                     Internet
            Traffic info & guidance   Corporate access / tele working   Intranet
            News                      Online e-mail                     E-mail
            Weather                   Real-time applications            Scheduler Access
            Ticket ordering           E-cash & payments                 Remote control
            Info- & Entertainment-    Audio & video on demand           Monitoring
            Services                  Video surveillance services
            Fleet management          (e.g. taxi, money transport)
                                      Remote healthcare




                                                                         WAP / WML
HTTP / HTML




  c@Irek Defée                        MULTIMEDIA SYSTEMS
                APPLICATION AREAS

 Business                              Private
 • Intranet access                     • Websurfing
 • Tele working                        • Electronic payment
 • Online e-mail / fax                   services
                                       • Mobile banking
 With focus on                         With focus on
 • Reliability                         • Price
 • Sufficient data rates               • Price
 • Ease of Use                         • Price


 Best addressed by                      Best addressed by

         HSCSD                                   GPRS

c@Irek Defée             MULTIMEDIA SYSTEMS
• 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
• SIGNAL MODULATION TECHNOLOGY
 IS WIDEBAND WCDMA,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
What is UMTS? Called popularly 3G

  •Universal Mobile Telecommunications
  Service

  •Member of IMT-2000 family

  •Global multimedia

  •Replacement (complement) for GSM

 c@Irek Defée   MULTIMEDIA SYSTEMS
Spectrum allocation for UMTS

   • 2x60MHz paired spectrum + 20 MHz
   and 15 MHz unpaired = 155 MHz




 c@Irek Defée   MULTIMEDIA SYSTEMS
 UTRA – UMTS TERRESTRIAL RADIO ACCESS

UTRA Key Parameters


                             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

c@Irek Defée             MULTIMEDIA SYSTEMS
       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
                     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
                                      HSDPA data rates
 Category            Max. number of                      Modulation                    Max. data rate
                      HS-DSCH codes                                                        [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

    The maximum data rate is theoretical peak rate for single user, effective data rate is in the range
    1-2 Mb/s



c@Irek Defée                            MULTIMEDIA SYSTEMS
                                   HSUPA
    • High Speed Uplink Packet Access
    • Information is sent from the users
     HSUPA is similar to HSDPA, speed lower
       HSUPA Category           Max Uplink Speed
       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




c@Irek Defée                    MULTIMEDIA SYSTEMS
               PERSONAL WIRELESS
                (Ad-Hoc) NETWORKS




c@Irek Defée        MULTIMEDIA SYSTEMS
                      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
                             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
               Frequency Hopping Spread Spectrum

     • FHSS uses narrowband
       carrier
           – Carrier changes frequency           F   80
             between time slices                 r
                                                 e   60
     • The receiver must know the                q
                                                 u   40
       pattern according to which                e
       the frequency is changing                 n   20
                                                 c
     • To an unintended receiver                 y   10
       the signal appears to be
                                                          1   2    3     4   5
       short duration impulse
                                                                  Time
       noise


c@Irek Defée                MULTIMEDIA SYSTEMS
                Direct Sequence Spread Spectrum

     • DSSS generates a redundant bit
       pattern for each bit to be
       transmitted                                  One

     • The longer the pattern,
                                                          Zero
           – 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
               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
                              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
                 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
           What Does Bluetooth Do?


Landline

                                             Cable
                                          Replacement

           Data/Voice
            Access
            Points


                        Personal Ad Hoc
                           Networks
                        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
                                      Radio Protocol
                       Frame                                                    Frame
               fk              fk+1                                      fk             fk+1

               One
Master         Slot
              Packet                    Master              Three Slot Packet




                            One
                                                                                         One
    Slave                   Slot
                           Packet        Slave                                           Slot
                                                                                        Packet



             625 us                               625 us
            One Slot                             One Slot

•      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)
                    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
               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
                              The Piconet                                     IDa
                              IDd                                             IDd

                IDa               D                    IDa                        P

                  A                                      M

                       IDe                                        IDe
                              E                                              sb
                                                 IDa
          IDb     B                              IDb     S             IDa
                        IDc       C                                    IDc        S




• 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                                 IDa

• Non-piconet devices are in standby
• Piconet Addressing                                         sb

   –   Active Member Address (AMA, 3-bits)
   –   Parked Member Address (PMA, 8-bits)                   M    or     S

                                                             P
                    Network Topology
• Radio Designation
  – Connected radios can be master or              S
     slave                                M
                                                           P
                                                                    M
  – Radios are symmetric
     (same radio can be                           sb   P

     master or slave)
• Piconet                                 S
                                                               sb
                                              P
  – Master can connect to seven                    S                    S

     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!
                  Bluetooth Baseband Protocol
    • There are altogether 7 states a              Standby
      Bluetooth device can have:
    • Standby: Waiting to join a piconet           Inquiry           Page
    • Inquire: Ask about radios to connect to
    • Page: Connect to a specific radio
                                                   Transmit       Connected
    • Connected: Actively on a piconet
      (master or slave)
    • PARK / HOLD: Low power connected              Park             Hold
      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
               Functional Overview
• Standby
                                  Unconnected                   Standby
  –   Waiting to join a piconet     Standby
• Inquire
  –   Ask about radios
      to connect to                                                Ttypical=2s

• Page                            Connecting                Inquiry                     Page
  –   Connect to a specific         States

      radio
                                                                                     Ttypical=0.6s
• Connected                                     Transmit
                                                                        Connected
  –   Actively on a piconet         Active
                                    States
                                                  data
                                                  AMA
                                                                          AMA
      (master or slave)
• Park/Hold                                          Ttypical=2 ms                  Ttypical=2 ms
  –   Low Power connected
      states                                     Releases
                                  Low Power                 PARK                       HOLD
                                                  AMA
                                                            PMA                        AMA
                                    States       Address
                           Bluetooth Architecture
                                                                Applications
     •    RF: Radio transmitter/receiver,
          frequency hopping
                                                            TCP / IP,          C
     •    BASEBAND: Piconet and channel
          definition, low-level packet definition           WAP,SDP,           O
                                                            RFCOMM             N
     •    LINK MANAGER: Defines encryption,
          authentication, SCO mode, low-power               etc.               T
          mode                                                                 R
     •    L2CAP: Link Layer Control And                                        O
                                                               L2CAP
          Adaptation defines a simple data link     Audio                      L
          protocol on top of baseband                          Link Manager
     •    CONTROL: Host Controller Interface
          provides a common interface between               Baseband
          the Bluetooth host and a Bluetooth
          module (e.g., USB, UART, RS232).
                                                               RF
     •    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.

c@Irek Defée                  MULTIMEDIA SYSTEMS
                        What Is Bluetooth?
         Applications
TCP/IP HID   RFCOMM              Application Framework
                                      and Support

           Data                  Host Controller Interface

         L2CAP                       Link Manager and
Audio
         Link Manager     LMP             L2CAP

        Baseband
                                     Radio & Baseband
          RF

 • A hardware description
 • An application framework
                     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
                           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
                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
               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
               BLUETOOTH APPLICATIONS




c@Irek Defée         MULTIMEDIA SYSTEMS
               BLUETOOTH APPLICATIONS




c@Irek Defée         MULTIMEDIA SYSTEMS
               BLUETOOTH APPLICATIONS




c@Irek Defée         MULTIMEDIA SYSTEMS
                BLUETOOTH APPLICATIONS




PAYING FOR TICKETS AND ACCESS IN TRAIN STATION
 c@Irek Defée         MULTIMEDIA SYSTEMS
               BLUETOOTH APPLICATIONS




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….
 c@Irek Defée   MULTIMEDIA SYSTEMS

				
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