Download - What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture

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  • What is Mobile Computing?Wireless Communication SystemsMobile Communication Systems ArchitectureKey Technologies of Mobile ComputingApplications

  • Heterogeneous Wireless Communication WorldDAB: Digital Audio BroadcastVHE: Virtual Home Environment DVB-T: Digital Video Broadcast TerrestrialUMTS: Universal Mobile Telecommunication System

  • Wireless NetworksWireless communication networksIEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20Mobile communication networksGSMGPRSWCDMAHSPA+LTE

  • IEEE 802Refers to a family of IEEE standards dealing with local area networks and metropolitan area networksThe services and protocols specified in IEEE 802 map to the lower two layersData LinkLogical Link Control (LLC) Media Access Control (MAC)PhysicalIEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20

  • IEEE 802 Standards

  • WWAN / WMAN / WLAN / WPAN

  • Note: NFC (Near Field Communication)A short-range high frequency wireless communication technology which enables the exchange of data between devices over about a 10 centimetre (around 4 inches) distanceThe technology is a simple extension of the ISO/IEC 14443 proximity-card standard (contactless card, RFID) that combines the interface of a smartcard and a reader into a single device

  • An NFC device can communicate with both existing ISO/IEC 14443 smartcards and readers, as well as with other NFC devices, and is thereby compatible with existing contactless infrastructure already in use for public transportation and paymentNFC technology is currently mainly aimed at being used with mobile phones

  • Three main use cases for NFCcard emulation: the NFC device behaves like an existing contactless cardreader mode: the NFC device is active and read a passive RFID tag, for example for interactive advertisingP2P mode: two NFC devices are communicating together and exchanging information

  • ApplicationsMobile ticketing in public transport an extension of the existing contactless infrastructureMobile payment the device acts as a debit/ credit payment cardSmart poster the mobile phone is used to read RFID tags on outdoor billboards in order to get info on the moveBluetooth pairing pairing of Bluetooth devices with NFC bringing them close together and accepting the pairing

  • Other applicationsElectronic ticketing airline tickets, concert/event tickets, and othersElectronic moneyTravel cardsIdentity documentsMobile commerceElectronic keys car keys, house/office keys, hotel room keys, etc.NFC can be used to configure and initiate other wireless network connections such as Bluetooth, Wi-Fi or Ultra-wideband

  • IEEE 802.11 Standard and AmendmentsIEEE 802.11 - The WLAN standard was original 1 Mbit/s and 2 Mbit/s, 2.4 GHz RF and infrared [IR] standard (1997), all the others listed below are Amendments to this standard, except for Recommended Practices 802.11F and 802.11T.IEEE 802.11a - 54 Mbit/s, 5 GHz standard (1999, shipping products in 2001)IEEE 802.11b - Enhancements to 802.11 to support 5.5 and 11 Mbit/s, 2.4 GHz (1999)IEEE 802.11c Bridge operation procedures; included in the IEEE 802.1D standard (2001)IEEE 802.11d - International (country-to-country) roaming extensions (2001)IEEE 802.11e - Enhancements: QoS, including packet bursting (2005)IEEE 802.11f - Inter-Access Point Protocol (2003) Withdrawn February 2006IEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20

  • IEEE 802.11g - 54 Mbit/s, 2.4 GHz standard (backwards compatible with b) (2003)IEEE 802.11h - Spectrum Managed 802.11a (5 GHz) for European compatibility (2004)IEEE 802.11i - Enhanced security (2004)IEEE 802.11j - Extensions for Japan (2004)IEEE 802.11-2007 - A new release of the standard that includes amendments a, b, d, e, g, h, i & j. (July 2007)IEEE 802.11k - Radio resource measurement enhancements (2008)IEEE 802.11n - Higher throughput improvements using MIMO (multiple input, multiple output antennas) (September 2009)IEEE 802.11p - WAVE Wireless Access for the Vehicular Environment (such as ambulances and passenger cars) (working June 2010)IEEE 802.11r - Fast roaming Working "Task Group r" - (2008)IEEE 802.11s - Mesh Networking, Extended Service Set (ESS) (working September 2010)

  • IEEE 802.11T Wireless Performance Prediction (WPP) - test methods and metrics Recommendation cancelledIEEE 802.11u - Interworking with non-802 networks (for example, cellular) (working September 2010)IEEE 802.11v - Wireless network management (working June 2010)IEEE 802.11w - Protected Management Frames (September 2009)IEEE 802.11y - 3650-3700 MHz Operation in the U.S. (2008)IEEE 802.11z - Extensions to Direct Link Setup (DLS) (August 2007 - December 2011)IEEE 802.11aa - Robust streaming of Audio Video Transport Streams (March 2008 - June 2011)IEEE 802.11mb Maintenance of the standard. Expected to become 802.11-2011. (ongoing)IEEE 802.11ac - Very High Throughput < 6 GHz (September 2008 - December 2012)IEEE 802.11ad - Extremely High Throughput 60 GHz (December 2008 - December 2012)

  • IEEE 802.11 / Wi-Fi [/WaFa/]Wireless Fidelity ()A wireless-technology brand owned by the Wi-Fi alliancePromotes standards with the aim of improving the interoperability of wireless local area network products based on the IEEE 802.11 standards

  • Common applications for Wi-FiInternet and VoIP phone access, gamingnetwork connectivity for consumer electronics such as televisions, DVD players, and digital camerasWi-Fi Alliancea consortium of separate and independent companiesagrees on a set of common interoperable products based on the family of IEEE 802.11 standards

  • IEEE 802.11 Infrastructure ModeUses fixed base stations (infrastructure) which are responsible for coordinating communication between the mobile hosts (nodes)

  • IEEE 802.11 Ad Hoc ModeMobile nodes communicate with each other through wireless medium without any fixed infrastructure

  • Mobile Ad Hoc Networks (MANET)Host moves frequentlyTopology changes frequently

    No cellular infrastructureMulti-hop wireless links Data must be routed via intermediate nodes

  • 802.11 /11a/11b/11g/11n

  • IEEE 802.11nImprove network throughput over 802.11a and 802.11gwith a significant increase in the maximum raw data rate from 54 Mbit/s to 600 Mbit/s with the use of four spatial streams at a channel width of 40 MHzIn spatial multiplexinga high rate signal is split into multiple lower rate streamseach stream is transmitted from a different transmit antenna in the same frequency channel

  • 802.11n uses MIMO (Multiple Input Multiple Output)

    WirelessTransmitter

    ADC&Tx/Rx

    ADC&Tx/Rx

    ADC&Tx/Rx

    ADC&Tx/Rx

    WirelessReceiver

    Signal 1

    Signal 2

    High Data Rate

    High Data Rate

    Analog Front End duplication

    Analog Front End duplication

    Basic two-antenna MIMO system with two-stream SDM(Spatial Division Multiplexing) example

  • IEEE 802.11p (VANET) MotivationVehicular Ad hoc NETwork (VANET)Safetyon US highways (2004)42,800 fatalities, 2.8 million injuries~$230.6 billion cost to societyEfficiencytraffic jams waste time and fuelin 2003, US drivers lost a total of 3.5 billion hours and 5.7 billion gallons of fuel to traffic congestionProfitsafety features and high-tech devices have become product differentiators

  • VANET-based Emergency Vehicle Warning System http://www.youtube.com/watch?v=yqtLvZrz2qE Ford's "Talking" Vehicles - Car-to-Car Communication Demo http://www.youtube.com/watch?v=XBqCAVwQv0E BMW Car-to-X Communication http://www.youtube.com/watch?v=JzgwlXzO6v0 InfoFueling network http://www.youtube.com/watch?v=Cc19mcnzvpE* Ford Demonstrates Vehicle-to-Vehicle Communication for Increased Safety http://www.youtube.com/watch?v=RrCyl6pOAC0

  • What is VANET?

  • Components in a VANETMoving vehicles with On-Board Unit (OBU)Road Side Units (RSU)local broadcasting informationIEEE 802.11 access point

  • On-Board Unit (OBU)Vehicle OBUWinXP devicesWindows mobile PDAsGPS tracker without user interfaceText-based OBUsPedestrian OBUGPS phonePersonal tracker

  • Smart VehicleA modern vehicle is a network of sensors/actuators on wheels !

  • VANET Architecture

  • Differences between VANET and MANET

    VANETsMANETsHighly mobile nodes moving in the same or opposite directionsNodes move randomlyNetwork shape can be best described by either a one-dimensional line or a stripA square or torus shapeWith location information and mapWithout location informationRely heavily on broadcast transmission to disseminate traffic related information to all reachable nodes (one to all & all to all)A query for a route to a certain host (one to one & one to all)Energy supported by carEnergy supported by battery(Energy conservation)EmergencyNon-emergencyTopology changes frequentlyTopology changes slowly

  • Vehicle Communication (VC) VC promises safer roads

  • more efficient driving

  • more fun

  • VANET ApplicationsCongestion detectionVehicle platooningRoad conditions warningCollision alertStoplight assistantEmergency vehicle warningDeceleration warningToll collectionBorder clearanceAdaptive cruise controlDrive-through paymentMerge assistance

  • A Taxonomy of Vehicular Communication Systems

  • Communication TypesRoadside-to-Vehicle Communications (RVC)Inter-Vehicle Communications (IVC)Hybrid-Vehicle Communications (HVC)+

  • Inter-vehicle communication (IVC) SystemsCompletely infrastructure-freeOnly onboard units (OBUs) are needed

  • IVC systemsSIVC (Single-hop Inter-Vehicle Communication)applications of short-range communicationse.g., lane merging, automatic cruise controlMIVC (Multihop Inter-Vehicle Communication)applications of long-range communicationse.g., traffic monitoring(a) SIVC(b) MIVC

  • Roadside-to-Vehicle Communication (RVC) SystemsCommunication between roadside infrastructure (RSU) and OBU Two types of infrastructures Sparse RVC (SRVC) systemUbiquitous RVC (URVC) system

  • RVC Systems - SRVCProvide communication services at hot spotsExamplesa busy intersection scheduling its traffic lighta gas station advertising its existence (and prices)parking availability at an airport

  • RVC Systems - URVCProvide all roads with high-speed communication Require considerable investments for providing full (even significant) coverage of existing roadways

  • Hybrid Vehicular Communication (HVC) SystemsExtend the transmission range of RVC systemsVehicles communicate with roadside infrastructure even when they are not in direct wireless range by using other vehicles as mobile routers

  • HVC Adv. & Disadv.Advantageless roadside infrastructureDisadvantagenetwork connectivity may not be guaranteed in scenarios with low vehicle density

  • Vehicular Ad Hoc Network (VANET)Message propagates to destination using a number of intermediate links

  • If vehicle mobility causes links to break, message rerouted using a different path

  • ChallengesPhysical layerlimited bandwidthLink layercongestion control, latency, throughput, fairness and scalabilityNetwork (routing) layerrapid topology changes and network fragmentation

  • WAVE (IEEE 1609) / DSRC (802.11p)

  • WAVE (Wireless Access in Vehicular Environments)

  • WAVEIEEE 1609Mode of operation used by IEEE 802.11 devices to operate in the DSRC band (5.850-5.925 GHz)Definesarchitecturecommunications modelmanagement structure security and physical accessPrimary architecture components are OBU, RSU, and WAVE interface

  • P1609.1 Resource ManagerP1609.2 Security Services for Applications and Management MessagesP1609.3 Networking ServicesP1609.4 Multi-Channel OperationsVAVE Standard Components

  • WAVE (IEEE 1609) / DSRC (802.11p)

  • DSRC(Dedicated Short Range Communications)ASTM Standard E2213-03, based on IEEE 802.11aName of the 5.9 GHz Band allocated for the ITS communications5.855-5.925 GHz rangedivided into 7 licensed channels (each 10 MHz)Short range radio300m (1000m max)High data rate6-27 MbpsASTM: American Society for Testing and Materials

  • Half-duplexstation can only send or transmit, but not both at the same timeLatency200 sCommunication modesvehicle to roadside & vehicle to vehicleDSRC devicesIEEE 802.11 systems using the WAVE mode of operation in the DSRC band

  • Based on ASTM Standard E2213-03IEEE 802.11a PHY: OFDM modulation IEEE 802.11 MAC: CSMA/CA IEEE 802.11e MAC enhancement: message prioritizationIEEE 802.11p Basis

  • Longer ranges of operation (up to ~1000 meters)High speed vehicles (up to ~500 km/h)Extreme multipath environment (many reflections with long delays)Need multiple overlapping ad-hoc networks to operate with extremely high quality of serviceSupport automotive applications (e.g. reliable broadcast)IEEE 802.11p Requirements

  • Control Channel (CCH)broadcast communication dedicated to short, high-priority, data and management framessafety-critical communication with low latenciesinitialization of two-way communication on SCHService Channel (SCH)two-way communication between RSU and OBU or between OBUsspecific applications, e.g. tolling, internet accessdifferent kinds of applications can be executed in parallel on different service channelsIEEE 802.11p Multi-Channel

  • DSRC Channel Allocation7 licensed channels (each 10 MHz)

  • DSRC Channel Allocation

  • DSRC

  • How DSRC Works?RSUannounces to OBUs 10 times per second the applications it supportsOBUlistens on channel 172authenticates RSU digital signatureexecutes safety apps firstthen, switches channelsexecutes non-safety appsreturns to channel 172 and listens

  • IEEE 1609.4 Extension for multi-channel coordination

  • Channel CoordinationEach Universal Time Coordinated (UTC) second is split into 10 Sync Intervals (each 100ms)Every Sync Interval is composed of alternatingCCH Interval (50ms): all WAVE devices have to monitor the CCH SCH Interval (50ms): nodes may switch to a SCH (RX or TX) Synchronization is performed via GPS

  • IEEE 802.11p Media Access Control (MAC)Based on Distributed Control Function (DCF) with CSMA/CACSMA/CAif the channel is sensed busy before transmission then the transmission is deferred for a random intervalBasic access mode and RTS/CTS mode are used on SCH

  • DCF: basic access modeA node transmits a DATA packet if it senses the channel to be idleThe receiverupon receiving an error-free packet, returns an ACKThe senderif the transmitting node does not get an ACK back, it enters into back-off and retransmits after the back-off periodBasic access mode suffers from hidden node problem

  • ABCHidden Node problemA is sending to BC is ready to transmit to Bit does not detect carrier and thus begins transmissionthis produces a collision at B Cs carrier sense did not provide the necessary information since station A was hidden from itRTS/CTS solves the hidden terminal problem!

  • DCF: RTS/CTS modeWhen a node A wants to send a packet to node B, it initially sends a Request-to-Send (RTS)A

  • Upon correctly receiving the RTS, node B responds with Clear-to-Send (CTS) B

  • After receiving the CTS, node A sends the DATA packet to node BBA

  • If node B receives the DATA packet correctly, it sends an Acknowledgment (ACK) back to node AAny node that hears an RTS or a CTS is prohibited from transmitting any signal for a period that is encoded in the duration field of the received RTS or CTS

  • The duration fields in RTS and CTS are set such that nodes A and B will be able to complete their communication within the prohibited period (Network Allocation Vector, NAV)Finally, if a node does not get a response to an RTS or a DATA packet, it enters into an exponential backoff mode

  • The dark bars below node C and D indicates their NAV

  • Backoff IntervalWhen channel is busy, choose a backoff interval in the range [0, cw]Count down the backoff interval when medium becomes idleCount down is suspended if medium becomes busy againWhen backoff interval reaches 0, transmit RTSBinary exponential backoff in 802.11 DCFwhen a node fails to receive CTS, cw is doubled up (up to an upper bound, cwmax)when a data transfer completes successfully, cw is reset to cwmin

  • IEEE 802.11p MAC Channel Access

  • IEEE 802.15The 15th working group of the IEEE 802 and specializes in Wireless PAN (Personal Area Network) standardsIEEE 802.15.1IEEE 802.15.1-2002a Wireless PAN standard based on Bluetooth v1.1 specifications including a media access control and physical layer specificationIEEE 802.15.1-2005based upon the additions incorporated into Bluetooth v1.2

    IEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20

  • the IEEE Study Group discontinues their relationship with the Bluetooth SIG (the later versions of Bluetooth will not become future IEEE standards)Bluetooth specificationsBluetooth 1.0 and 1.0BBluetooth 1.1Bluetooth 1.2 (data rate: 1Mbps)[not IEEE standard]Bluetooth 2.0 + EDR (Extended Data Rate)Bluetooth 2.1 + EDR (data rate: 3Mbps)Bluetooth 3.0 + HS (High Speed) (data rate: perhaps 24Mbps)Bluetooth V4.0 (Ble; Bluetooth low energy) (data rate: perhaps 24Mbps)

  • IEEE 802.16 Standards (WiMAX)IEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20

  • 802.16 WiMAX (Worldwide Interoperability for Microwave Access)WirelessMANA telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access Enable the delivery of last mile wireless broadband access as an alternative to cable and DSL

  • Intel WiMAX Vision*

  • WiMAX for Fixed and Mobile Access*CPE (Customer Premise Equipment)/

  • WiMAX Consumer Last Mile*

  • WiMAX Backhaul for Business*

  • WiMAX Nomadic / Portable*

  • 2008.11.13 HTC Max 4GGSM / WiMAX*

  • IEEE 802.16 Operation Modes / TopologiesPoint to MultiPoint (PMP) / star topologyMesh mode / mesh topologyMobile Multihop Relay (MMR) / tree topology

  • IEEE 802.16 EntitiesBS Base Stationcentral role in PMP modecoordination role in resource managementconnection/gateway point to other networks (backhaul, core IP, Internet)SS Subscriber Stationfixed stationMS mobile stationMSS - Multiple Subscriber Station (playing role of an AP for LAN/WLAN)in-door or out-doorRS Relay stationused in Mobile Multihop Relay (MMR)*

  • 802.16 Relevant Standards802.16d (2004) basic fixed mode- standardPMP / mesh modes, 70 Mbps802.16e (2005) (Mobile WiMAX)lower data rate, 15 Mbpsfull nomadic and mobile use including handoverenhancements to 802.16-2004better support for QoSscalable OFDMAsupports devices : mobile smart phones, PDAs, notebooks, laptops*

  • 802.16j Mobile Multihop Relay (MMR)enhance the normal PMP frame structurebackward compatible with PMP modenew relay networking protocolsmulti-hop relay connections between SS/MS and BScoverage extensionsthroughput enhancementactually not mesh mode but tree topology*

  • 802.16mamendment for advanced air interfacebased on IEEE 802.16e-2005expected data rates100 Mbps for mobile applications 1 Gbps for fixed applicationsspectral efficiency, improve voice capacity, reduce latencysupport for location-based servicesimprove multicast broadcast services*

  • IEE 802.16 Relevant Standards Evolution*

  • *Mobile WiMAX (IEEE 802.16e)To enable low-cost mobile Internet applicationsTo realize the convergence of mobile and fixed broadband access in a single air interface and network architecture

  • Mobile WiMAX enabling a variety of usage models in the same network

  • Mobile WiMAX Technology and Network Evolution Roadmap

  • WiMAX Network Reference Model

  • WiMAX Logical Network EntitiesMobile Station (MS)generalized user equipment set providing wireless connectivity between a single or multiple hosts and the WiMAX networkin this context the term MS is used more generically to refer to both mobile and fixed device terminals

  • Access Service Network (ASN)a complete set of network functions required to provide radio access to MSlayer 2 (L2) connectivity with the MS according to IEEE 802.16 standards and WiMAX system profiletransfer of authentication, authorization, and accounting (AAA) messages to the home network service provider (HNSP)preferred NSP discovery and selectionrelay functionality for establishing layer 3 (L3) connectivity with MS (i.e., IP address allocation)radio resource managementto enable mobility, the ASN may also support ASN and CSN anchored mobility, paging and location management, and ASN-CSN tunneling

  • Base station (BS)primarily consists of radio related functions of an ASN interfacing with an MS over-the-air link according to MAC and PHY specificationsASN gateway (ASN-GW)an aggregation of centralized functions related to QoS, security, and mobility management for all the data connections served by its association with BSs through R6hosts functions related to IP layer interactions with CSN through R3interacts with other ASNs through R4 in support of mobility

  • Connectivity Service Network (CSN)a set of network functions that provide IP connectivity services to WiMAX subscriber(s)the CSN may further comprises network elements such as routers, AAA proxy /servers, home agent, and user databases as well as interworking gateways or enhanced network servers to support multicast and broadcast services and location-based services

  • key functionsIP address managementAAA proxy or serverQoS policy and admission control based on user subscription profilesASN-CSN tunneling supportsubscriber billing and interoperator settlementinter-CSN tunneling for roamingCSN-anchored inter-ASN mobilityconnectivity to Internet and managed WiMAX services such as IP multimedia services (IMS), location-based services, peer-to-peer services, and broadcast and multicast servicesover-the-air activation and provisioning of WiMAX devices

  • *WiMAX Reference PointsR1SS/MSASN802.16eR2SS/MSCSNIPR3ASNCSNAAAR4ASNR5CSNAAABillingR6BSASNBSASNR8BS

  • WiMAX Network uses IP Based Simple Protocol StructureSS/MSASNCSNBSASN-GW

  • MAC / PHY Protocol Structure in Mobile WiMAX Release 1.0

  • WiMAX MAC Layer (IEEE Std. 802.16-2004)

  • Service Specific Convergence Sublayer (CS)MACMACCS(Service Access PointSAP)IEEE 802.16-2004sub-layer(SDU)sub-layer(PDU)Common Part Sublayer (CPS)CPSMACsublayerCPSMAC SAPCSQoS802.16 MACMAC CPSSecurity Sublayer (SS)Key/

  • *WiMAX Network Architecture and Evolution(Release 1.0)ASN and CSN mobility (for mobility support)Paging and location managementIPv4 and IPv6 connectivityPreprovisioned/static QoSOptional radio resource management (RRM)Network discovery/selectionIP/Ethernet CS supportFlexible credentials, pre- and postpaid accountingRoaming (RADIUS only)3GPP I-WLAN compatible interworking

  • *Over-the-air (OTA) activation and provisioningLocation-based services (LBS)Multicast broadcast service (MBS)IMS integrationDynamic QoS and policy and charging (PCC) compatible with 3GPP Release 7Telephony VoIP with emergency call services and lawful interceptionFull NAP sharing supportHandover data integrityMultihost supportEthernet services, VLANEnhanced open Internet servicesDiameter-based AAAWiMAX Network Architecture and Evolution(Release 1.5)

  • *Multimedia session continuity3GPP/2 interworking (optimized handover )Network management, including self-organized /optimized networks (SONs)Seamless WiFi-WiMAX handoverRoaming enhancementsSupport for multihop relay stationsSupport for femto-cellsDevice reported metricsWiMAX Network Architecture and Evolution(Release 2.0)

  • 802.20 MBWA (Mobile Broadband Wireless Access)IEEE 802.20 or Mobile Broadband Wireless Access (MBWA)an IEEE Standard to enable worldwide deployment of multi-vendor interoperable mobile broadband wireless access networksa packet-based air interface designed for IP-based serviceslow-cost, always-on, and mobile broadband wireless networks, nicknamed as Mobile-Fithe goals of 802.20 and 802.16e, the so-called "mobile WiMAX", are similarIEEE 802.11IEEE 802.15IEEE 802.16IEEE 802.20

  • Technical descriptionIP roaming & handoff (more than 1 Mbps)new MAC and PHY with IP and adaptive antennasoptimized for full mobility up to vehicular speeds of 250 km/hoperates in licensed bands (below 3.5 GHz)utilizes packet architecturelow latency

  • WWAN / WMAN / WLAN / WPAN

    *Fidelty: ;AllianceAllianceConsortium*ADCAnalog-to-Digital Converter****RSURoad Side Unit**************Amendment()

    ***Green fieldIn wireless engineering jargon, a greenfield is a project which lacks any constraints imposed by prior networks.Today any new network designed from scratch to enable new Radio Access Network technologies (i.e 3G, 4G, Wi-MAX, etc..) are also referred to as "greenfield networks" or "greenfield projects".*****