2001/10/5 Prof. Huei-Wen Ferng 1 Chapter 3 Mobile Data Services and Technologies

2001/10/52001/10/5 Prof. Huei-Wen FerngProf. Huei-Wen Ferng 11

Chapter 3Chapter 3

Mobile Data Services and Mobile Data Services and TechnologiesTechnologies


Mobile Data ServicesMobile Data Services


ContentsContents

The RAM/Mobitex mobile data serviceThe RAM/Mobitex mobile data service The ARDIS/Modacom mobile data serviceThe ARDIS/Modacom mobile data service Cellular Digital Packet Data (CDPD)Cellular Digital Packet Data (CDPD) Data over analog and digital cellularData over analog and digital cellular Competing mobile data servicesCompeting mobile data services Paging and two-way pagingPaging and two-way paging Comparison of paging and cellularComparison of paging and cellular


The RAM/Mobitex Mobile Data ServiceThe RAM/Mobitex Mobile Data Service

This service is owned jointly by This service is owned jointly by Bell Bell SouthSouth and and RAMRAM in the US in the US

Protocol was developed by Protocol was developed by EricssonEricsson Data rateData rate

• 8 Kbps in the US ->19.2 Kbps (CDPD)8 Kbps in the US ->19.2 Kbps (CDPD)• 9.6 Kbps in the other parts of the world9.6 Kbps in the other parts of the world


Some of early applicationsSome of early applications Point of sale where dial-up is not available: Point of sale where dial-up is not available:

MasterCardMasterCard Inventory control of rental cars: National Car Inventory control of rental cars: National Car

RentalRental Train exchange yards: ConrailTrain exchange yards: Conrail Passenger check-in: British AirwayPassenger check-in: British Airway Field service: GE consumer serviceField service: GE consumer service Public safety: Chicago Parking AuthorityPublic safety: Chicago Parking Authority Insurance claimsInsurance claims TransportationTransportation E-mailE-mail


Countries that installed Mobitex netCountries that installed Mobitex networksworks

AustraliaAustralia CanadaCanada FinlandFinland NetherlandsNetherlands NorwayNorway SwedenSweden UKUK USUS

Rest of Europe (later)Rest of Europe (later) Latin America (later)Latin America (later) The Pacific Rim (lateThe Pacific Rim (late

r)r)


What would you need to use the RWhat would you need to use the RAM/Mobitex networkAM/Mobitex network

HardwareHardware• RadioRadio• ModemModem• TerminalTerminal

Application SWApplication SW• System integratorsSystem integrators• Software companiesSoftware companies

Network usageNetwork usage• MobitexMobitex

Remark: the combinRemark: the combination unit of radio anation unit of radio and modem is called d modem is called MMobidemobidem


Specifications of MobidemSpecifications of Mobidem

Portable wireless modem and radioPortable wireless modem and radio Connectible to RS-232 serial portConnectible to RS-232 serial port 8 Kbps migrating to 19.2 Kbps8 Kbps migrating to 19.2 Kbps 1 pound1 pound 3.3X2.68X7.87 in3.3X2.68X7.87 in Max transmit power: 2 WMax transmit power: 2 W >10 hours per battery charge>10 hours per battery charge Support for nationwide roamingSupport for nationwide roaming


Operations of MobitexOperations of Mobitex The Mobidem automatically registers with the The Mobidem automatically registers with the

nearest base stationnearest base station The network is a store-and-forward networkThe network is a store-and-forward network The Mobidem scans the network for incoming The Mobidem scans the network for incoming

messagesmessages It alerts the user’s of incoming messagesIt alerts the user’s of incoming messages The Mobidem stores the messages if the termiThe Mobidem stores the messages if the termi

nal is not availablenal is not available The network stores the messages if the MobidThe network stores the messages if the Mobid

em is not availableem is not available


Subscription Type for the HostsSubscription Type for the Hosts

CCITT X.25CCITT X.25 ISO/HDLCISO/HDLC SNA 3270SNA 3270 Mobitex asynchronous communicationsMobitex asynchronous communications


Subscription Types for the Mobile Subscription Types for the Mobile TerminalTerminal

Continuous linkage to a particular Continuous linkage to a particular terminalterminal

Personal subscription that is linked to Personal subscription that is linked to a person, not a terminal, in which a person, not a terminal, in which case the user logs in via name and case the user logs in via name and passwordpassword

Group subscriptions that can consists Group subscriptions that can consists of mobile and fixed usersof mobile and fixed users


Mobitex PartnersMobitex Partners

IBMIBM HPHP MotorolaMotorola IntelIntel FujitsuFujitsu EricssonEricsson AT&TAT&T


Developer and System Integrator Developer and System Integrator PartnersPartners

DECDEC LotusLotus NovellNovell WordPerfectWordPerfect


The ARDIS/Modacom Mobile Data The ARDIS/Modacom Mobile Data ServiceService

Countries have installed ModacomCountries have installed Modacom• USUS• GermanyGermany• UKUK• Hong KongHong Kong

Data rateData rate• US: 4.8 Kbps -> 19.2 Kbps (CDPD)US: 4.8 Kbps -> 19.2 Kbps (CDPD)• The other parts of the world: 9.6 KbpsThe other parts of the world: 9.6 Kbps


Applications of ModacomApplications of Modacom Field techniques can Field techniques can

accessaccess• Dispatch info.Dispatch info.• Diagnostic info.Diagnostic info.• Service historyService history• Parts availabilityParts availability

Messenger serviceMessenger service• Receive and dispatch Receive and dispatch

messages while making messages while making deliveriesdeliveries

• Notify customer that Notify customer that delivery was donedelivery was done

Salesperson canSalesperson can• Obtain latest product Obtain latest product

specificationsspecifications• Provide accurate price Provide accurate price

quotequote• Check product availabilityCheck product availability• Make the orderMake the order

Additional applicationsAdditional applications• Fleet managementFleet management• Insurance and financial Insurance and financial

servicesservices• Real time data Real time data

applicationsapplications• Point of sale (POS)Point of sale (POS)• TelemetryTelemetry• E-mailE-mail


InfoTACInfoTAC

The radio and modem The radio and modem combinationcombination

Specifications:Specifications:• Connects through RS-Connects through RS-

232 port232 port• Receives, stores, and Receives, stores, and

responds to messagesresponds to messages• Canned responses can Canned responses can

be programmedbe programmed• 10 KB buffer10 KB buffer• Transmit power: 3 WTransmit power: 3 W

• 6.8X3.3X3.3 inches6.8X3.3X3.3 inches• 18 ounces18 ounces• 4X20 line backlit LCD displ4X20 line backlit LCD displ

ayay• 8 hours battery life8 hours battery life• Compatible withCompatible with

ARDIS/ModacomARDIS/Modacom RAM/MobitexRAM/Mobitex


Cellular Digital Packet DataCellular Digital Packet Data Consortium of companiesConsortium of companies

• IBMIBM• 6 of the 7 ROBCs (Regional Bell Operating Compani6 of the 7 ROBCs (Regional Bell Operating Compani

es)es) Ameritech Mobile CommunicationsAmeritech Mobile Communications Bell Atlantic Mobile SystemsBell Atlantic Mobile Systems NYNEX Mobile CommunicationsNYNEX Mobile Communications Pac Tel CellularPac Tel Cellular Southwestern Bell Mobile SystemsSouthwestern Bell Mobile Systems US West New Vector GroupUS West New Vector Group

• McCaw Cellular CommunicationsMcCaw Cellular Communications• Contel CellularContel Cellular• GTE Mobile Communications GTE Mobile Communications


Four CDPD ApplicationsFour CDPD Applications

Transaction applicationsTransaction applications Interactive applicationsInteractive applications Broadcast applicationsBroadcast applications Multicast applicationsMulticast applications


Transaction ApplicationsTransaction Applications

Credit card Credit card authorization/transactiauthorization/transactionon

Package pickup, Package pickup, delivery, and trackingdelivery, and tracking

Fleet managementFleet management POSPOS Inventory controlInventory control Emergency servicesEmergency services

M-ES/vehicle theft M-ES/vehicle theft recoveryrecovery

Display of calling party Display of calling party name and numbername and number

Notice of voice mailNotice of voice mail E-mailE-mail Information retrieval Information retrieval

servicesservices TelemetryTelemetry


Examples of TelemetryExamples of Telemetry

Location serviceLocation service Vehicle statisticsVehicle statistics

• MileageMileage• SpeedSpeed• Engine statusEngine status

Burglar or fire alarm reportingBurglar or fire alarm reporting Vending machine statusVending machine status Weather statisticsWeather statistics Traffic statisticsTraffic statistics Field measurementsField measurements


Examples of Information RetrievalExamples of Information Retrieval

Weather report for a particular placeWeather report for a particular place Traffic report for a specific areaTraffic report for a specific area Directory assistance: White pagesDirectory assistance: White pages Local service assistance: Yellow Local service assistance: Yellow

pagespages Location and direction informationLocation and direction information Restaurant reservation serviceRestaurant reservation service


Interactive and Broadcast Apps.Interactive and Broadcast Apps.

Interactive: Remote access via direct Interactive: Remote access via direct network connection or via a packet network connection or via a packet assembly/disassemblyassembly/disassembly

BroadcastBroadcast• NewsNews• SportsSports• WeatherWeather• Advertising Advertising


Multicast ApplicationsMulticast Applications

A subscription to A subscription to obtain:obtain:• Market info.Market info.• Business newsBusiness news• News related to a News related to a

specific areaspecific area• Classifieds for a Classifieds for a

particular areaparticular area• Recreational info.Recreational info.

A subscription to a A subscription to a private bulletin to private bulletin to obtain:obtain:• Service bulletinsService bulletins• Company functionsCompany functions• Product info.Product info.• Fraud warningsFraud warnings


Data over Analog and Digital Data over Analog and Digital CellularCellular

Data over analog cellularData over analog cellular• Data rate: up to 14.4 KbpsData rate: up to 14.4 Kbps

Data over digital cellularData over digital cellular• Data rate:Data rate:

Voice grade channel: 9.6 KbpsVoice grade channel: 9.6 Kbps GSM: 270 KbpsGSM: 270 Kbps Digital TDMA: 30 KbpsDigital TDMA: 30 Kbps


Competing Mobile Data ServicesCompeting Mobile Data Services


Paging and Two-Way PagingPaging and Two-Way Paging

Paging stepsPaging steps• Someone dialing the page numberSomeone dialing the page number• Central controller broadcasts the page Central controller broadcasts the page

to local controllerto local controller• Local controller broadcasts to base Local controller broadcasts to base

stationsstations• Base station broadcasts to end usersBase station broadcasts to end users


One-Way PagingOne-Way Paging


One-Way PagingOne-Way Paging


Two-Way PagingTwo-Way Paging

Two kindsTwo kinds• Two-way asymmetrical paging networksTwo-way asymmetrical paging networks• Two-way symmetrical paging networksTwo-way symmetrical paging networks

Spectrum: 900 MHzSpectrum: 900 MHz Bandwidth: 50 MHzBandwidth: 50 MHz


Asymmetrical Two-Way PagingAsymmetrical Two-Way Paging

Two separate networks: Two separate networks: • One for outgoing trafficOne for outgoing traffic• The other for incoming trafficThe other for incoming traffic

Incoming networks receives more Incoming networks receives more dense than the outgoing dense than the outgoing transmitters, transmitters, • e.g., a simple query may receive a much e.g., a simple query may receive a much

longer responselonger response


Asymmetrical Two-Way PagingAsymmetrical Two-Way Paging


Comparison of Paging to CellularComparison of Paging to Cellular

Paging is inexpensive, ubiquitous, Paging is inexpensive, ubiquitous, but with limited applicationsbut with limited applications

It may become very powerful when It may become very powerful when combined with a PDA because of its combined with a PDA because of its simplicitysimplicity


Comparison of Paging to CellularComparison of Paging to Cellular


Mobile Data Mobile Data TechnologiesTechnologies


ContentsContents

RAM/Mobitex network technologiesRAM/Mobitex network technologies Motorola ARDIS/Modacom network techMotorola ARDIS/Modacom network tech

nologiesnologies CDPD network technologiesCDPD network technologies Cell size classificationCell size classification


RAM/Mobitex Network TechnologieRAM/Mobitex Network Technologiess

It offered by Ericsson in most parts of It offered by Ericsson in most parts of the world. In the US, it is jointly the world. In the US, it is jointly owned by RAM and Bell Southowned by RAM and Bell South

The Network Control Center is the The Network Control Center is the heart of the networkheart of the network

Its protocol was developed by Its protocol was developed by Ericsson and is openEricsson and is open


Parameters (in the US)Parameters (in the US)

Tx. Frequency: 896-902 GHzTx. Frequency: 896-902 GHz Rx. Frequency: 935-941 GHzRx. Frequency: 935-941 GHz 10-30 channel pairs in each metropolita10-30 channel pairs in each metropolita

n arean area Channel spacing: 12.5 KHzChannel spacing: 12.5 KHz


Air InterfaceAir Interface ROSI: RadiO SignalingROSI: RadiO Signaling 0.3 GMSK: Gaussian Minimum Shift Keying wit0.3 GMSK: Gaussian Minimum Shift Keying wit

h BT=0.3h BT=0.3 Block interleavingBlock interleaving 16-bit CRC for error detection16-bit CRC for error detection Reduced Hamming code for error correctionReduced Hamming code for error correction Selective Automatic Repeat RequestSelective Automatic Repeat Request Channel access mechanism: reservation slotteChannel access mechanism: reservation slotte

d ALOHAd ALOHA Collisions are detected by the lack of ACKCollisions are detected by the lack of ACK


The Terminal Interface (DLC)The Terminal Interface (DLC)

MASC: RAM/Mobitex Asynchronous ComMASC: RAM/Mobitex Asynchronous Communicationsmunications

Handles data between the terminal and Handles data between the terminal and MobidemMobidem

Provides control and status monitoring Provides control and status monitoring of the Mobidemof the Mobidem


The Network LayerThe Network Layer

MPAKMPAK Max packet size of 512 bytes of info., pluMax packet size of 512 bytes of info., plu

s headers header 24-bit addressing for the Mobitex numbe24-bit addressing for the Mobitex numbe

rr The transport layer protocolThe transport layer protocol

• MTP/1MTP/1


Mobitex PacketMobitex Packet


Mobitex Protocol LayerMobitex Protocol Layer


Gateway ServiceGateway Service Available viaAvailable via

• Mobitex directly: MobigateMobitex directly: Mobigate• The third partyThe third party

Mobigate to hostsMobigate to hosts• TCP/IPTCP/IP• X.25X.25• SNA 3270SNA 3270

Third party gateways to hostsThird party gateways to hosts• SNASNA• AS 400AS 400• DECNetDECNet


ARDIS/Modacom Network TechnolARDIS/Modacom Network Technologiesogies

In most parts of world provided by Motorola: called MIn most parts of world provided by Motorola: called Modacomodacom

In US: called ARDISIn US: called ARDIS ARDIS: separate company from IBMARDIS: separate company from IBM The network intelligence is concentrated in the hubThe network intelligence is concentrated in the hub Hub is connected to the Radio Frequency Network CoHub is connected to the Radio Frequency Network Co

ntrol Points (RF NCP)ntrol Points (RF NCP) InfoTAC: the combination of radio and modemInfoTAC: the combination of radio and modem MAC protocol: slotted ALOHAMAC protocol: slotted ALOHA 25 KHz channel spacing25 KHz channel spacing


The Terminal InterfaceThe Terminal Interface

MDC 4800, the original protocolMDC 4800, the original protocol• 4.8 Kbps4.8 Kbps• FSKFSK

RD LAP 19.2RD LAP 19.2• 19.2 Kbps19.2 Kbps• Four level FSKFour level FSK

RAM/MobitexRAM/Mobitex• 8 Kbps8 Kbps• GMSKGMSK


The Terminal Interface (cont’d)The Terminal Interface (cont’d)

The MDC 4800 protocol is quite robust:The MDC 4800 protocol is quite robust:• Error detection and correction using 16 bits Error detection and correction using 16 bits

for 32 bits of info.for 32 bits of info.• Employing convolutional code: up 28% of erEmploying convolutional code: up 28% of er

ror correctionror correction• Bits are interleavedBits are interleaved


CDPD Network TechnologiesCDPD Network Technologies

The basic idea was proposed by a scientist at IBM, Dr. Vic MooreThe basic idea was proposed by a scientist at IBM, Dr. Vic Moore


The Services Provided by CDPD The Services Provided by CDPD

19.2 Kbps19.2 Kbps Connectionless serviceConnectionless service Point-to-pointPoint-to-point MulticastMulticast BroadcastBroadcast SecuritySecurity

• Authentication of usersAuthentication of users• AuthorizationAuthorization• Encryption of dataEncryption of data


CDPD Reference ModelCDPD Reference Model


Functions of the Air Link NetworkFunctions of the Air Link Network

Overlays existing cell site equipmentOverlays existing cell site equipment Accepts and forwards traffic to and from M-ESAccepts and forwards traffic to and from M-ES

ss Over the A-InterfaceOver the A-Interface At the PHY and MAC layersAt the PHY and MAC layers Manages channel allocationManages channel allocation Two types of air link channels (IS-533)Two types of air link channels (IS-533)

• MDBS to M-Es: forward/downlinkMDBS to M-Es: forward/downlink• M-Es to MDBS: reverse/uplinkM-Es to MDBS: reverse/uplink

Data stream is assigned a Channel Stream IdeData stream is assigned a Channel Stream Identifier (CSI)ntifier (CSI)


Functions of MD-ISFunctions of MD-IS

Uses and controls MDBSsUses and controls MDBSs Control mobile data linkControl mobile data link Manages mobilityManages mobility Does not perform complex routing decisDoes not perform complex routing decis

ions since they are included in the functiions since they are included in the function of the ISson of the ISs


Air Link NetworkAir Link Network


Functions of ISFunctions of IS

Perform network layer functionsPerform network layer functions Route datagrams among F-ESs MD-ISsRoute datagrams among F-ESs MD-ISs SupportSupport

• Internet protocol (IP)Internet protocol (IP)• Connectionless network protocol (CLNP)Connectionless network protocol (CLNP)

Can be composed of several administrative doCan be composed of several administrative domainsmains

Connection oriented communications are proConnection oriented communications are provided by transport layer in end systemvided by transport layer in end system


CDPD Switched NetworkCDPD Switched Network


Network ConfigurationNetwork Configuration


CDPD Data Carriage ProtocolCDPD Data Carriage Protocol

MDLP: Mobile Data Link ProtocolMDLP: Mobile Data Link Protocol SNDCP: Sub Network Dependent Convergence ProtocolSNDCP: Sub Network Dependent Convergence Protocol


Cell Size ClassificationCell Size Classification

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2001/10/5 Prof. Huei-Wen Ferng 1 Chapter 3 Mobile Data Services and Technologies