c@irek deféemultimedia systems other networks. c@irek deféemultimedia systems cable modems

c@Irek Defée MULTIMEDIA SYSTEMS

OTHER NETWORKS


CABLE MODEMS


• 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


• 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


• 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


• 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


• SIGNAL MODULATION IN CABLE MODEMS

QPSK - QUADRATURE PHASE SHIFT

KEYING

QAM – QUADRATURE AMPLITUDE

MODULATION

. PHASE OF THE SIGNAL IS CHANGED (HERE FOUR VALUES ARE USED)

00

01

1110


• PHASE AND AMPLITUDE CAN BE

CHANGED – QAM

HERE WE CAN ASSIGN3 BITS TO EACH VALUEOF AMPLITUDE AND PHASE

000

THE MORE AMPLITUDE AND PHASE VALUES THE MOREINFORMATION CAN BE SEND, BUT SIGNAL IS MORE SENSITIVE TO NOISE


16-QAM BIT ASSIGNMENT


• 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


• 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


• 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


• CABLE TV NETWORK CAN BE

SPLIT AROUND HEADEND

AMPLIFIERS

USERS (100-200 PER HEADEND)

DISTRIBUTION (FIBER OPTICS)


• 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


WIRLESS SYSTEMS

CELLULAR NETWORKS


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 Accessto the reception and systems are called CDMA, FDMA,...


THESE ACCESS SYSTEMS CAN BE USED IN ALL KINDOF 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

TRANSMITTERIN THE CENTEROF EACH CELL


• 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


- IN ADDITION GSM THE SYSTEM HAS ALSO A KIND OF CDMA – FREQUENCY HOPPING:FREQUENCY BAND CAN BE CHANGED FROMTIME SLOT TO TIME SLOT ACCORDING TOSPECIFIC 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). MINIMUMCELL SIZE IS 100-500M(?). SO WE CAN GETHIGH DENSITY OF USERS/km2


• 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


• GSM UPGRADES

- GPRS – PACKET SWITCHING,

CONNECTIONLESS SERVICE

- HSCSD – HIGH SPEED CIRCUIT

SWITCHED DATA

- EDGE – BANDWIDTH INCREASE WITH NEW MODULATION BASED ON 8-PSK


144 kbps 144 kbpsISDN

Standards Implementation

2048 kbps 384 kbpsWCDMA

Maximum Data Rate for New Systems

470 kbps < 470 kbpsEDGE

171 kbps 57.6 kbpsGPRS

57.6 kbps 28.8 kbpsHSCSD

9.6 kbps 9.6 kbpsGSM Data


• 1. GPRS

- PACKET SWITCHING RUNNING IN

FREE CAPACITY OF GSM SLOTS

- VERY FLEXIBLE

- SEVERAL CODING SCHEMES

- FLEXIBLE USE OF TIME SLOTS


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

TDMA frame

TRX : GPRS & GSM

0 7TS number

GPRS onlyGSM only GSM or GPRS


Coding schemes in GPRS• 4 coding schemes for packet transfers

thus data rates increase

CS

information protection

data rates (Kbits/s)

CS4 : no protection21.4

CS1 : same as GSM measurements reporting

13.4

15.6

9. 05

CS2 CS3


GPRS coverage• New design thresholds

– depending on coding scheme– due to decreasing protection / interferences

• On existing networks– "concentric" GPRS coverage

GSM only cellenabling

GPRSGSM

coverage

CS1

CS2

CS3CS4


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 CS2There is no significant change in coverage from GSM to GPRS CS1 and CS2

Cell Radius


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


BTSMSC/VLR

SGSN GGSN

BSC

PCU

GMSC

GPRS BackboneIP Network

BG CG DNS

BG = Border GatewayCG = Charging GatewayDNS = Domain Name SystemsPCU = Packet Control UnitSGSN = Serving GPRS Support NodeGGSN = Gateway GPRS Support NodeBTS = Base Transceiver StationBSC = Base Station ControllerMSC = Mobile Services Switching CentreGMSC = Gateway MSC

HLR

New GPRS Network Elements

Existing Elements

New Elements


ApplicationApplication

IP / X.25IP / X.25

SNDCPSNDCP

LLCLLC

RLCRLC

MACMAC

GSM PLGSM PL

SNDCPSNDCP

BSSGPBSSGP

L1bisL1bis

RLCRLC

MACMAC

GSM PLGSM PL

LLC RelayLLC Relay

L2L2

L1L1

L2L2

L1L1

IPIP

GTPGTP

IP / X.25IP / X.25

UmUm GbGb GnGn GiGiMSMS BSSBSS SGSNSGSN GGSNGGSN

FrameFrameRelayRelay

FrameFrameRelayRelay

BSSGPBSSGP

L1bisL1bis

LLCLLC

GTPGTP

IPIP

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

TLLITLLI

TIDTID

IPIP


X25 end to end

GGSNSGSN

GPRS IP backbone

GTP tunnel layerLLC tunnel layer

IP end to end

RADIO specificL2

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


• 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?


up- / downlink 100% coverage 95% coverage 100% coverage 95% coverage1 + 1 9.6 14.4 9.6 13.22 + 2 19.2 28.8 19.2 26.41 + 3 --- ---- 28.8 39.61 + 4 --- ---- 38.4 53.8

HSCSD User Data Ratetransparent service non transparent service

GPRS User Data Rate

Coding # of timeslotsScheme 1 2 3 4 5 6 7 8

CS-1 9,05 18,1 27,15 36,2 45,25 54,3 63,35 72,4CS-2 13,4 26,8 40,2 53,6 67 80,4 93,8 107,2CS-3 15,6 31,2 46,8 62,4 78 93,6 109,2 124,8CS-4 21,4 42,8 64,2 85,6 107 128,4 149,8 171,2


GSM Wireless Data Development Steps

High Speed Data CircuitsHSCSD n*14.4 (3*14.4 = 43.2)

High Speed Packet CapabilitiesGPRS (e.g. 3* 13.4 = 40.2)

3Q 1999

3Q 2000


High Speed data circuitsHSCSD n*14.4 (3*14.4 = 43.2)

MSCBSC

BTS

BTS

UDIISDN

GSM

IWE

PSTN

Internet

CorporateNetworks

LAN


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: 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.


MSCBSS

BTSGSM

HLR

GPRS backboneFR / ATM

GGSN

GGSN

GGSN

SGSN Border GW

CorporateNetworks

otherPLMN

Internet

High Speed Packet CapabilitiesGPRS (e.g. 3* 13.4 = 40.2)


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.


New Mobile Applications


SmartMessaging

BankingTraffic info & guidanceNewsWeatherTicket orderingInfo- & Entertainment-ServicesFleet management

HSCSD

File transferCorporate access / tele workingOnline e-mailReal-time applicationsE-cash & paymentsAudio & video on demandVideo surveillance services(e.g. taxi, money transport)Remote healthcare

GPRS

InternetIntranetE-mailScheduler AccessRemote controlMonitoring

WAP / WMLHTTP / HTML


APPLICATION AREAS

Business Private

• Intranet access• Tele working• Online e-mail / fax

• Websurfing• Electronic payment

services• Mobile banking

With focus on• Reliability• Sufficient data rates• Ease of Use

With focus on• Price• Price• Price

Best addressed by

HSCSDHSCSD

Best addressed by

GPRSGPRS


• THIRD GENERATION CELLULAR SYSTEMS

THESE SYSTEMS ARE BEING

DESIGNED FROM GROUND UP FOR

MULTIMEDIA APPLICATIONS:

- HIGH BANDWIDTH STREAMING

SERVICES

- PACKET BASED APPLICATIONS


• 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


What is UMTS? Called popularly 3G

•Universal Mobile Telecommunications Service

•Member of IMT-2000 family

•Global multimedia

•Replacement (complement) for GSM


Spectrum allocation for UMTS

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


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

UTRA – UMTS TERRESTRIAL RADIO ACCESS


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


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.


HSDPA data ratesCategory Max. number of

HS-DSCH codesModulation Max. data rate

[Mbit/s]

1 5 QPSK and 16-QAM 1.2









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 range1-2 Mb/s


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 7 (3GPP Rel7) 11.5 Mbit/s


PERSONAL WIRELESS (Ad-Hoc) NETWORKS


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.


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


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

1 2 3 4 5

Frequency

80

60

40

20

10

Time


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

One

Zero


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


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.

Who Is Bluetooth?Harald Blaatand “Bluetooth” II,

King of Denmark 940-981Son of Gorm the Old (King of Denmark)

and Thyra Danebod (daughter of King Ethelred of England)

This is one of two Runic stones This is one of two Runic stones erected in his capitol city erected in his capitol city of Jelling (central Jutland)of Jelling (central Jutland)This is the front of the stone This is the front of the stone

depicting the chivalry of Haralddepicting the chivalry of HaraldThe stone’s inscription (“runes”) say:The stone’s inscription (“runes”) say:

Harald christianized the DanesHarald christianized the DanesHarald controlled Denmark Harald controlled Denmark

and Norwayand NorwayHarald thinks notebooks and Harald thinks notebooks and

cellular phones should cellular phones should seamlessly communicateseamlessly communicate

Personal Ad Hoc Personal Ad Hoc NetworksNetworks

Cable Cable ReplacementReplacement

LandlineLandline

Data/Voice Data/Voice Access Access PointsPoints

What Does Bluetooth Do?


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)

O neSlot

Packet

Three S lot Packet

Fram e

M aster

S lave

625 usO ne S lo t

fk fk+1

O neSlot

Packet

Fram e

M aster

S lave

625 usO ne S lo t

fk fk+1

O neSlot

Packet

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)


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)


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)

A

D

C

B

E

ID b

ID a

ID c

ID d

ID e

M

P

S

S

sb

ID a

ID c

ID d

ID a

IDa

IDa

ID e

ID b

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)

ID a

P

M Soror

sb

MM

S

S S

S

P

sb

sb

P

P

Network Topology• Radio Designation

– Connected radios can be master or slave

– Radios are symmetric (same radio can bemaster 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!


Bluetooth Baseband Protocol

• There are altogether 7 states a Bluetooth device can have:

• 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

• 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.

Standby

Inquiry Page

Transmit Connected

Park Hold

InquiryInquiry PagePage

ConnectedConnectedAMAAMA

TransmitTransmitdatadataAMAAMA

TTtypical=0.6stypical=0.6s

TTtypical=2stypical=2s

HOLDHOLDAMAAMA

PARKPARKPMAPMA

TTtypical=2 mstypical=2 ms TTtypical=2 mstypical=2 ms

ReleasesReleasesAMAAMA

AddressAddressLow PowerLow Power

StatesStates

ActiveActiveStatesStates

StandbyStandby

ConnectingConnectingStatesStates

UnconnectedUnconnectedStandbyStandby

Det

ach

Det

ach

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


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

Baseband

Link Manager

L2CAPAudio

TCP / IP,WAP,SDP,RFCOMMetc.

CONTROL

Applications• 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).

Application Framework Application Framework and Supportand Support

Link Manager and Link Manager and L2CAPL2CAP

Radio & BasebandRadio & Baseband

Host Controller Host Controller InterfaceInterface

RFRF

BasebandBaseband

AudioAudioLink ManagerLink Manager LMPLMPL2CAPL2CAP

TCP/IPTCP/IP HIDHID RFCOMMRFCOMM

ApplicationsApplications

DataDataC

ontr

ol

Con

trol

What Is Bluetooth?

• 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


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)


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.


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.



PAYING FOR TICKETS AND ACCESS IN TRAIN STATION


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 deféemultimedia systems other networks. c@irek deféemultimedia systems cable modems

Documents

access systems

cellular systems

bandwidth slide

mbs slide

problem slide

allocated slide

user slide

cell slide