Presentation on theme: "Gunawan Wibisono Dept Teknik Elektro FTUI"— Presentation transcript:
1 Gunawan Wibisono Dept Teknik Elektro FTUI Chapter 2Wireless Network(Review)Gunawan WibisonoDept Teknik Elektro FTUI
2 Agenda Introduction GSM UMTS/IMT-2000 3G and 4G Satellite Communications
3 Wireless Communication System Channel code wordSourceEncoderChannelMod-ulatorMessage SignalModulatedTransmitted SignalCommunication ChannelUserSourceDecoderChannelDemod-ulatorEstimate ofMessage signalchannel code wordReceivedSignalZ. Ghassemlooy
4 Communication Channels A channel is a path between two communication devicesChannel capacity: How much data can be passed through the channel (bit/sec)Also called channel bandwidthThe smaller the pipe the slower data transfer!Consists of one or more transmission mediaMaterials carrying the signalTwo types:Physical: wire cableWireless: Airdestination network serverT1 linesT3 lines
5 Physical Transmission Media A tangible mediaExamples: Twisted-pair cable, coaxial cable, Fiber-optics, etc.Twisted-pair cable:One or more twisted wires bundled together (why?)Made of copperCoax-Cable:Consists of single copper wire surrounded by three layers of insulating and metal materialsTypically used for cable TVFiber-optics:Strands of glass or plastic used to transmit lightVery high capacity, low noise, small size, less suitable to natural disturbances
6 Physical Transmission Media plastic outer coatingwoven or braided metalinsulating materialcopper wiretwisted-pair cabletwisted-pair wireprotective coatingglass claddingoptical fiber core
7 Wireless Transmission Media Broadcast RadioDistribute signals through the air over long distanceUses an antennaTypically for stationary locationsCan be short rangeCellular RadioA form of broadcast radio used for mobile communicationHigh frequency radio waves to transmit voice or dataUtilizes frequency-reuse
8 Wireless Transmission Media MicrowavesRadio waves providing high speed transmissionThey are point-to-point (can’t be obstructed)Used for satellite communicationInfrared (IR)Wireless transmission media that sends signals using infrared light- waves - Such as?
9 Physical Transmission Media Wireless channel capacity:100 Mbps is how many bits per sec?Which is bigger:10,000 Mbps, 0.01Tbps or 10Gbps?
10 Networks Collection of communication systems connected together used to transfer information (voice, data, datagram, video), share resources, etc.What is the largest network?Characterized based on their geographical coverage, speed, capacitiesNetworks are categorized based on the following characteristics:Network coverage: LAN, MAN, WANNetwork topologies: how the communication systems are connected togetherNetwork technologiesNetwork architecture
11 Network Coverage Segmentasi Pengguna Wireless Segmentation of wireless user
12 Network Coverage Local Area Networks: Used for small networks (school, home, office)Examples and configurations:Wireless LAN or Switched LANATM LAN, Frame Ethernet LANPeer-2-PEER: connecting several computers together (<10)Client/Server: The serves shares its resources between different clientsMetropolitan Area NetworkBackbone network connecting all LANsCan cover a city or the entire countryWide Area NetworkTypically between cities and countriesTechnology:Circuit Switch, Packet Switch, Frame Relay, ATMExamples:Internet P2P: Networks with the same network software can be connected together (Napster)
13 LAN v.s WANLAN - Local Area Network a group of computers connected within a building or a campus (Example of LAN may consist of computers located on a single floor or a building or it might link all the computers in a small company.WAN - A network consisting of computers of LAN's connected across a distance WAN can cover small to large distances, using different topologies such as telephone lines, fiber optic cabling, satellite transmissions and microwave transmissions.
14 Network TopologiesConfiguration or physical arrangement in which devices are connected togetherBUS networks: Single central cable connected a number of devicesEasy and cheapPopular for LANsRING networks: a number of computers are connected on a closed loopCovers large distancesPrimarily used for LANs and WANsSTAR networks: connecting all devices to a central unitAll computers are connected to a central device called hubAll data must pass through the hubWhat is the problem with this?Susceptible to failure
15 Network Topologies personal computer personal computer host computer printerfile serverpersonal computer
16 Network ArchitectureRefers to how the computer or devices are designed in a networkBasic types:Centralized – using mainframesPeer-2-Peer:Each computer (peer) has equal responsibilities, capacities, sharing hardware, data, with the other computers on the peer-to-peer networkGood for small businesses and home networksSimple and inexpensiveClient/Server:All clients must request service from the serverThe server is also called a hostDifferent servers perform different tasks: File server, network server, etc.clientserverlaser printer
17 (Data) Network Technologies Vary depending on the type of devices we use for interconnecting computers and devices togetherEthernet:LAN technology allowing computers to access the networkSusceptible to collisionCan be based on BUS or STAR topologiesOperates at 10Mbps or 100Mbps, (10/100)Fast Ethernet operates at 100 MbpsGigabit Ethernet (1998 IEEE 802.3z)10-Gigabit Ethernet (10GE or 10GbE or 10 GigE)10GBASE-R/LR/SR (long range short range, etc.)Physical layerGigabit Ethernet using optical fiber, twisted pair cable, or balanced copper cable
18 (Data) Network Technologies Token RingLAN technologyOnly the computer with the token can transmitNo collisionTypically devices can be connected togetherTCP/IP and UDPUses packet transmission802.11Standard for wireless LANWi-Fi (wireless fidelity) is used to describe that the device is in family or standardsTypically used for long range ( feet)Variations include: .11 (1-2 Mbps); .11a (up to 54 Mbps); .11b (up to 11 Mbps); .11g (54 Mbps and higher
19 (Data) Network Technologies Next generation wireless LAN technologyImproving network throughput (600 Mbps compared to 450 Mbps) – thus potentially supporting a user throughput of 110 Mbit/sWiMAXWorldwide Interoperability for Microwave AccessProvides wireless transmission of data from point-to-multipoint links to portable and fully mobile internet access (up to 3 Mbit/s)The intent is to deliver the last mile wireless broadband access as an alternative to cable and DSLBased on the IEEE (d/e) standard (also called Broadband Wireless Access)
20 Network Technologies Personal area network (PAN) A low range computer networkPANs can be used for communication among the personal devices themselvesWired with computer buses such as USB and FireWire.Wireless personal area network (WPAN)Uses network technologies such as IrDA, Bluetooth, UWB, Z-Wave and ZigBeeInternet Mobile ProtocolsSupporting multimedia Internet trafficIGMP & MBONE for multicastingRTP, RTCP, & RSVP (used to handle multimedia on the Internet)VoIPRTP: Real-time Transport Protocol
21 Network Technologies Zigbee Bluetooth IrDA RFID WAP High level communication protocols using small, low-power digital radios based on the IEEEWireless mesh networking proprietary standardBluetoothUses radio frequencyTypically used for close distances (short range- 33 feet or so)Transmits at 1MbpsUsed for handheld computers to communicate with the desktopIrDAInfrared (IR) light wavesTransfers at a rate of 115 Kbps to 4 MbpsRequires light-of-sight transmissionRFIDRadio frequency identificationUses tags which are places in itemsExample: merchandises, toll-tags, courtesy calls, sensors!WAPWireless application protocolData rate of kbps depending on the service typeUsed for smart phones and PDAs to access the Internet ( , web, etc)
22 Network Examples IEEE 802.15.4 Intranets Home networks Low-rate wireless personal area networks (LR-WPANs)Bases for e ZigBee, WirelessHART, and MiWi specificationAlso used for 6LoWPAN and standard Internet protocols to build a Wireless Embedded Internet (WEI)IntranetsUsed for private networksMay implement a firewallHardware and software that restricts access to data and information on a networkHome networksEthernetPhone lineHomeRF (radio frequency- waves)Intelligent home networkVehicle-to-Vehicle (car2Car) -A wireless LAN based communication system to guarantee European-wide inter-vehicle operabilityCar2Car Technology:
24 Network Example: Telephone Networks Called the Public Switched Telephone Network (PSTN)World-wide and voice oriented (handles voice and data)Data/voice can be transferred within the PSTN using different technologies (data transfer rate bps)Dial-up lines:Analog signals passing through telephone linesRequires modems (56 kbps transfer rate)ISDN lines:Integrated Services Digital NetworkDigital transmission over the telephone linesCan carry (multiplex) several signals on a single lineDSLDigital subscribe lineADSL (asymmetric DSL)receiver operated at 8.4 Mbps, transmit at 640 kbpsT-Carrier lines: carries several signals over a single line: T1,T3Frame RelayATM:Asynchronous Transfer ModeFast and high capacity transmitting technologyPacket technologySwitching Technologies:Technologies:Circuit SwitchingPacket SwitchingMessage SwitchingBurst Switching
30 Cellular Network Examples 0GSingle, powerful base station covering a wide area, and each telephone would effectively monopolize a channel over that whole area while in use (developed in 40’s)No frequency use or handoff (basis of modern cell phone technology)1GFully automatic cellular networksintroduced in the early to mid 1980s2GIntroduced in 1991 in Finland on the GSM standardOffered the first data service with person-to-person SMS text messaging
31 Cellular Network Examples 3G:Faster than PCS; Used for multimedia and graphicsCompared to 2G and 2.5G services, 3G allows simultaneous use of speech and data services and higher data rates (up to 14.4 Mbit/s on the downlink and 5.8 Mbit/s.4G:Fourth generation of cellular wireless;providing a comprehensive and secure IP based service to users "Anytime, Anywhere" at high data rates
32 GSM: Overview GSM formerly: Groupe Spéciale Mobile (founded 1982) now: Global System for Mobile CommunicationPan-European standard (ETSI, European Telecommunications Standardisation Institute)simultaneous introduction of essential services in three phases (1991, 1994, 1996) by the European telecommunication administrations (Germany: D1 and D2) seamless roaming within Europe possibletoday many providers all over the world use GSM (more than 130 countries in Asia, Africa, Europe, Australia, America)more than 100 million subscribers
33 Performance characteristics of GSM Communicationmobile, wireless communication; support for voice and data servicesTotal mobilityinternational access, chip-card enables use of access points of different providersWorldwide connectivityone number, the network handles localizationHigh capacitybetter frequency efficiency, smaller cells, more customers per cellHigh transmission qualityhigh audio quality and reliability for wireless, uninterrupted phone calls at higher speeds (e.g., from cars, trains)Security functionsaccess control, authentication via chip-card and PIN
34 Disadvantages of GSM There is no perfect system!! no end-to-end encryption of user datano full ISDN bandwidth of 64 kbit/s to the user, no transparent B-channelreduced concentration while drivingelectromagnetic radiationabuse of private data possibleroaming profiles accessiblehigh complexity of the systemseveral incompatibilities within the GSM standards
35 GSM: Mobile Services GSM offers Three service domains several types of connectionsvoice connections, data connections, short message servicemulti-service options (combination of basic services)Three service domainsBearer ServicesTelematic ServicesSupplementary Servicesbearer servicesMSGSM-PLMNtransitnetwork(PSTN, ISDN)source/destinationnetworkTEMTTER, SUm(U, S, R)tele services
36 Bearer ServicesTelecommunication services to transfer data between access pointsSpecification of services up to the terminal interface (OSI layers 1-3)Different data rates for voice and data (original standard)data service (circuit switched)synchronous: 2.4, 4.8 or 9.6 kbit/sasynchronous: bit/sdata service (packet switched)asynchronous: bit/s
37 Tele Services ITelecommunication services that enable voice communication via mobile phonesAll these basic services have to obey cellular functions, security measurements etc.Offered servicesmobile telephony primary goal of GSM was to enable mobile telephony offering the traditional bandwidth of 3.1 kHzEmergency number common number throughout Europe (112); mandatory for all service providers; free of charge; connection with the highest priority (preemption of other connections possible)Multinumbering several ISDN phone numbers per user possible
38 Tele Services II Additional services Non-Voice-Teleservices group 3 faxvoice mailbox (implemented in the fixed network supporting the mobile terminals)electronic mail (MHS, Message Handling System, implemented in the fixed network)...Short Message Service (SMS) alphanumeric data transmission to/from the mobile terminal using the signaling channel, thus allowing simultaneous use of basic services and SMS
39 Supplementary services Services in addition to the basic services, cannot be offered stand-aloneSimilar to ISDN services besides lower bandwidth due to the radio linkMay differ between different service providers, countries and protocol versionsImportant servicesidentification: forwarding of caller numbersuppression of number forwardingautomatic call-backconferencing with up to 7 participantslocking of the mobile terminal (incoming or outgoing calls)...
40 Architecture of the GSM system GSM is a PLMN (Public Land Mobile Network)several providers setup mobile networks following the GSM standard within each countrycomponentsMS (mobile station)BS (base station)MSC (mobile switching center)LR (location register)subsystemsRSS (radio subsystem): covers all radio aspectsNSS (network and switching subsystem): call forwarding, handover, switchingOSS (operation subsystem): management of the network
42 GSM: elements and interfaces radio cellBSSMSMSUmradio cellMSRSSBTSBTSAbisBSCBSCAMSCMSCNSSVLRVLRsignalingHLRISDN, PSTNGMSCPDNIWFOOSSEIRAUCOMC
43 GSM: system architecture radio subsystemnetwork and switching subsystemfixed partner networksMSMSISDN PSTNUmMSCAbisBTSBSCEIRBTSSS7HLRVLRBTSBSCISDN PSTNBTSAMSCBSSIWFPSPDN CSPDN
44 System architecture: radio subsystem network and switching subsystemMSMSComponentsMS (Mobile Station)BSS (Base Station Subsystem): consisting ofBTS (Base Transceiver Station): sender and receiverBSC (Base Station Controller): controlling several transceiversInterfacesUm : radio interfaceAbis : standardized, open interface with 16 kbit/s user channelsA: standardized, open interface with 64 kbit/s user channelsUmAbisBTSBSCMSCBTSABTSMSCBSCBTSBSS
45 System architecture: network and switching subsystem network subsystemfixed partner networksComponentsMSC (Mobile Services Switching Center):IWF (Interworking Functions)ISDN (Integrated Services Digital Network)PSTN (Public Switched Telephone Network)PSPDN (Packet Switched Public Data Net.)CSPDN (Circuit Switched Public Data Net.)DatabasesHLR (Home Location Register)VLR (Visitor Location Register)EIR (Equipment Identity Register)ISDN PSTNMSCEIRSS7HLRVLRISDN PSTNMSCIWFPSPDN CSPDN
46 Radio subsystemThe Radio Subsystem (RSS) comprises the cellular mobile network up to the switching centersComponentsBase Station Subsystem (BSS):Base Transceiver Station (BTS): radio components including sender, receiver, antenna - if directed antennas are used one BTS can cover several cellsBase Station Controller (BSC): switching between BTSs, controlling BTSs, managing of network resources, mapping of radio channels (Um) onto terrestrial channels (A interface)BSS = BSC + sum(BTS) + interconnectionMobile Stations (MS)
47 GSM: cellular network segmentation of the area into cells possible radio coverage of the cellidealized shape of the celluse of several carrier frequenciesnot the same frequency in adjoining cellscell sizes vary from some 100 m up to 35 km depending on user density, geography, transceiver power etc.hexagonal shape of cells is idealized (cells overlap, shapes depend on geography)if a mobile user changes cells handover of the connection to the neighbor cell
48 Base Transceiver Station and Base Station Controller Tasks of a BSS are distributed over BSC and BTSBTS comprises radio specific functionsBSC is the switching center for radio channels
49 Mobile station Terminal for the use of GSM services A mobile station (MS) comprises several functional groupsMT (Mobile Terminal):offers common functions used by all services the MS offerscorresponds to the network termination (NT) of an ISDN accessend-point of the radio interface (Um)TA (Terminal Adapter):terminal adaptation, hides radio specific characteristicsTE (Terminal Equipment):peripheral device of the MS, offers services to a userdoes not contain GSM specific functionsSIM (Subscriber Identity Module):personalization of the mobile terminal, stores user parametersRSUmTETAMT
50 Network and switching subsystem NSS is the main component of the public mobile network GSMswitching, mobility management, interconnection to other networks, system controlComponentsMobile Services Switching Center (MSC) controls all connections via a separated network to/from a mobile terminal within the domain of the MSC - several BSC can belong to a MSCDatabases (important: scalability, high capacity, low delay)Home Location Register (HLR) central master database containing user data, permanent and semi-permanent data of all subscribers assigned to the HLR (one provider can have several HLRs)Visitor Location Register (VLR) local database for a subset of user data, including data about all user currently in the domain of the VLR
51 Mobile Services Switching Center The MSC (mobile switching center) plays a central role in GSMswitching functionsadditional functions for mobility supportmanagement of network resourcesinterworking functions via Gateway MSC (GMSC)integration of several databasesFunctions of a MSCspecific functions for paging and call forwardingtermination of SS7 (signaling system no. 7)mobility specific signalinglocation registration and forwarding of location informationprovision of new services (fax, data calls)support of short message service (SMS)generation and forwarding of accounting and billing information
52 Operation subsystemThe OSS (Operation Subsystem) enables centralized operation, management, and maintenance of all GSM subsystemsComponentsAuthentication Center (AUC)generates user specific authentication parameters on request of a VLRauthentication parameters used for authentication of mobile terminals and encryption of user data on the air interface within the GSM systemEquipment Identity Register (EIR)registers GSM mobile stations and user rightsstolen or malfunctioning mobile stations can be locked and sometimes even localizedOperation and Maintenance Center (OMC)different control capabilities for the radio subsystem and the network subsystem
54 Security in GSM Security services 3 algorithms specified in GSM access control/authenticationuser SIM (Subscriber Identity Module): secret PIN (personal identification number)SIM network: challenge response methodconfidentialityvoice and signaling encrypted on the wireless link (after successful authentication)anonymitytemporary identity TMSI (Temporary Mobile Subscriber Identity)newly assigned at each new location update (LUP)encrypted transmission3 algorithms specified in GSMA3 for authentication (“secret”, open interface)A5 for encryption (standardized)A8 for key generation (“secret”, open interface)“secret”:A3 and A8 available via the Internetnetwork providers can use stronger mechanisms
55 Data services in GSM IData transmission standardized with only 9.6 kbit/sadvanced coding allows 14,4 kbit/snot enough for Internet and multimedia applicationsHSCSD (High-Speed Circuit Switched Data)already standardizedbundling of several time-slots to get higher AIUR (Air Interface User Rate) (e.g., 57.6 kbit/s using 4 slots, 14.4 each)advantage: ready to use, constant quality, simpledisadvantage: channels blocked for voice transmission
56 Data services in GSM II GPRS (General Packet Radio Service) packet switchingusing free slots only if data packets ready to send (e.g., 115 kbit/s using 8 slots temporarily)standardization 1998, introduction 2000?advantage: one step towards UMTS, more flexibledisadvantage: more investment neededGPRS network elementsGSN (GPRS Support Nodes): GGSN and SGSNGGSN (Gateway GSN)interworking unit between GPRS and PDN (Packet Data Network)SGSN (Serving GSN)supports the MS (location, billing, security)GR (GPRS Register)user addresses
60 DECTDECT (Digital European Cordless Telephone) standardized by ETSI (ETS x) for cordless telephonesstandard describes air interface between base-station and mobile phoneDECT has been renamed for international marketing reasons into „Digital Enhanced Cordless Telecommunication“Characteristicsfrequency: MHzchannels: 120 full duplexduplex mechanism: TDD (Time Division Duplex) with 10 ms frame lengthmultplexing scheme: FDMA with 10 carrier frequencies, TDMA with 2x 12 slotsmodulation: digital, Gaußian Minimum Shift Key (GMSK)power: 10 mW average (max. 250 mW)range: ca 50 m in buildings, 300 m open space
61 DECT system architecture reference model VDBD2PAPTFTlocalnetworkHDBPAPTD1globalnetworkFTlocalnetwork
62 UMTS and IMT-2000Proposals for IMT-2000 (International Mobile Telecommunications)UWC-136, cdma2000, WP-CDMAUMTS (Universal Mobile Telecommunications System) from ETSIUMTSUTRA (UMTS Terrestrial Radio Access)enhancements of GSMEDGE (Enhanced Data rates for GSM Evolution): GSM up to 384 kbit/sCAMEL (Customized Application for Mobile Enhanced Logic)VHE (virtual Home Environment)fits into GMM (Global Multimedia Mobility) initiative from ETSIrequirementsmin. 144 kbit/s rural (goal: 384 kbit/s)min. 384 kbit/s suburban (goal: 512 kbit/s)up to 2 Mbit/s city
64 UMTS FDD frame structure W-CDMAMHz uplinkMHz downlinkchipping rate: Mchip/ssoft handoverlocalization of MS (ca. 20 m precision)complex power control (1600 power control cycles/s)superframe720 ms12...697071frame10 ms12...131415slot625 µspilotTPCTFIuplink DPCCH625 µsdatauplink DPDCH625 µspilotTPCTFIdatadownlink DPCHDPCCHDPDCHTPC: Transmit Power ControlTFI: Transport Format IdentifierDPCCH: Dedicated Physical Control ChannelDPDCH: Dedicated Physical Data ChannelDPCH: Dedicated Physical Channel
65 UMTS TDD frame structure 10 ms12...131415slot625 µsdatamidampledataGPtraffic burstGP: Guard PeriodW-TDMA/CDMA2560 chips per slotsymmetric or asymmetric slot assignment to up/downlinktight synchronization neededsimpler power control ( power control cycles/s)
68 BackgroundWiMAXStandar IEEE Broadband Wireless AccessDelivers > 1 Mbps per userJarak jangkauan hingga 50 kmPenggunaan adaptive modulation dapat mengatasi data rate yang bervariasiDapat beroperasi pada non-line of site (NLOS)1.5 to 20 MHz channelsMendukung sessions per channel yang efisienBeroperasi pada licensed and unlicensed spectrumQoS untuk voice, video, and T1/E1
71 BackgroundWhy WiMAXTingginya permintaan akses internet kecepatan tinggiInfrastruktur yang ada masih belum mencukupiPenggunaan GPRS/3G, user memerlukan perangkat yang lebih canggihPenggelaran WiMAX yang relatif murah
72 Mendukung coverage yang luas, outdoors maupun indoor BackgroundMengapa WiMAXSolusi BWA pada harga yang murah (satu standar global, beroperasi pada lisensi dan non lisensi)Mendukung coverage yang luas, outdoors maupun indoorMenghasilkan “new business opportunities” untuk BWA di negara berkembang dan rural areaKomplemen solusi jaringan selular 2G/3GKomplemen solusi jaringan Wireless LAN & WAN
75 Evolution WiMAX Technologies LOS & NLOSMobileSeamlessHandoverPortableHot ZoneSession continuityNomadicHot ZoneNo HandoverFixedWireless DSLWireless PCPortability with Simple MobilityFeederSME/SOHO AccessWireless DSLWirelessDSLHot ZoneNomadicityWireless PCFull-Mobility
76 Standards for Business Evolution WiMAX TechnologiesProtocol test suiteContributions to air interface base specsDefine regulatory requirementsWiMax ForumStandards for BusinessAir interface base specsMobility extensionManagement specsMarketing and promotionCertificationNetwork interface specs
77 Evolution WiMAX Technologies a line-of-sight (LOS) capabilitypoint to multipoint Broadband WirelessLMDS (Local Multipoint Distribution Service)(10–66 GHz band)a single carrier (SC) physical (PHY) standarda non-line-of-sight (NLOS) capabilityMobile WiMAXpoint to multipoint capability in the 2–11 GHz bandOrthogonal Frequency Division Multiplex (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA)Scalable OFDMA (SOFDMA)Advanced antenna diversity schemes, and hybrid automatic repeat-request (HARQ)Adaptive Antenna Systems (AAS) and MIMO technologyDenser sub-channelization, thereby improving indoor penetrationIntroducing Turbo Coding and Low-Density Parity Check (LDPC)
78 Evolution WiMAX Technologies StandardDescriptionStatusFixed Broadband Wireless Access (10–63 GHz)SupersededRecommended practice for coexistence802.16c-2002System profiles for 10–63 GHz802.16a-2003Physical layer and MAC definitions for 2–11 GHzP802.16bLicense-exempt frequencies (Project withdrawn)WithdrawnP802.16dMaintenance and System profiles for 2–11 GHz (Project merged into )MergedAir Interface for Fixed Broadband Wireless Access System (rollup of , a, c and P802.16d)P aCoexistence with 2–11 GHz and 23.5–43.5 GHz (Project merged into )Recommended practice for coexistence (Maintenance and rollup of and P a)CurrentEvolution WiMAX Technologies
79 Evolution WiMAX Technologies 802.16f-2005 StandardDescriptionStatus802.16f-2005Management Information Base (MIB) forSuperseded/CorCorrections for fixed operations (co-published with e-2005)802.16e-2005Mobile Broadband Wireless Access System802.16k-2007Bridging of (an amendment to IEEE 802.1D)Current802.16g-2007Management Plane Procedures and ServicesP802.16iMobile Management Information Base (Project merged into )MergedAir Interface for Fixed and Mobile Broadband Wireless Access System (rollup of , /Cor 1, e, f, g and P802.16i)802.16j-2009Multihop relay802.16h-2010Improved Coexistence Mechanisms for License-Exempt OperationP802.16mAdvanced Air Interface with data rates of 100 Mbit/s mobile & 1 Gbit/s fixedIn ProgressP802.16nHigher Reliability NetworksEvolutionWiMAX Technologies
81 Universität Karlsruhe Institut für Telematik WiMAX ArchitecturePhysical layerMobilkommunikationSS 1998A pre-WiMAX CPE of a 26 km (16 mi) connection mounted 13 metres (43 ft) above the ground (2004, Lithuania).WiMAX base station equipment with a sector antenna and wireless modem on topA WiMAX Gateway which provides VoIP, Ethernet and WiFi connectivityA WiMAX USB modem for mobile internetIllustration of a WiMAX MIMO boardProf. Dr. Dr. h.c. G. KrügerE. Dorner / Dr. J. Schiller
82 OFDM – Modulation for High Data Rate 85WiMAX ForumTechnologyOFDM – Modulation for High Data Rate
85 WiMAX Architecture MAC (data link) layer- Technology The WiMAX MAC uses a scheduling algorithm for which the subscriber station needs to compete only once for initial entry into the network.In addition to being stable under overload and over-subscription, the scheduling algorithm can also be more bandwidth efficient.The scheduling algorithm also allows the base station to control Quality of service (QoS) parameters by balancing the time-slot assignments among the application needs of the subscriber stations.
86 Comparison of Mobile Internet Access methods Standard Family Primary UseRadio TechDownlink (Mbit/s)Uplink (Mbit/s)NotesLTEUMTS/4GS MGeneral 4GOFDMA/MIMO/SC- FDMA36080LTE-Advanced update expected to offer peak rates of at least 1 Gbit/s fixed speeds and 100 Mbit/s to mobile users.WiMAX802.16eMobile InternetMIMO-SOFDMA14435WiMAX update IEEE m expected offer up to 1 Gbit/s fixed speeds.Flash-OFDMFlash- OFDMMobile Internet mobility up to 200mph (350km/h)Mobile range 18miles (30km) extended range 34 miles (55km)HIPERMANOFDM56.9Wi-Fi(11n)Mobile InternetOFDM/MIMO(Supports 40MHz channel width)Antenna, RF front end enhancements and minor protocol timer tweaks have helped deploy long range P2P networks compromising on radial coverage, throughput and/or spectra efficiency (310km & 382km).iBurst802.20HC- SDMA/TDD/MIMO9536Cell Radius: 3–12 km Speed: 250kmph Spectral Efficiency: 13 bits/s/Hz/cell Spectrum Reuse Factor: "1"EDGE EvolutionGSMTDMA/FDD1.90.93GPP Release 7UMTS W-CDMA HSDPA+HSUPA HSPA+UMTS/3GS MGeneral 3GCDMA/FDD CDMA/FDD/MIMOHSDPA widely deployed. Typical downlink rates today 2 Mbit/s, ~200 kbit/s uplink; HSPA+ downlink up to 56 Mbit/s.UMTS-TDDCDMA/TDD16Reported speeds according to IPWireless using 16QAM modulation similar to HSDPA+HSUPA1xRTTCDMA2000Mobile phoneCDMA0.144Succeeded by EV-DOEV-DO 1x Rev. 0 EV-DO 1x Rev.A EV-DO Rev.BCDMA/FDDxNxNRev B note: N is the number of 1.25 MHz chunks of spectrum used.
87 LTE performance requirements MobilityOptimized for low mobility(0-15km/h) but supports high speedLatencyuser plane < 5mscontrol plane < 50 msImproved spectrum efficiencyCost-effective migration from Release 6 Universal Terrestrial Radio Access (UTRA) radio interface and architectureImproved broadcastingIP-optimizedScalable bandwidth of 20MHz, 15MHz, 10MHz, 5MHz and <5MHzCo-existence with legacy standards (users can transparently start a call or transfer of data in an area using an LTE standard, and, when there is no coverage, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS)
88 3GPP Long Term Evolution (LTE) 3GPP (LTE) is Adopting:OFDMA in DL with 64QAMAll IP e2e NetworkChannel BWs up to 20 MHzBoth TDD and FDD profilesFlexible Access NetworkAdvanced Antenna TechnologiesUL: Single-Carrier FDMA (SC-FDMA), (64QAM optional)LTE is adopting technology & features already available with Mobile WiMAXCan expect similar long-term performance benefits and trade-offs
89 Other Key Parameter Comparisons LTEMobile WiMAX Rel 1.5DuplexFDD and TDDFrequency Band for Performance Analysis2000 MHz2500 MHzChannel BWUp to 20 MHzDownlinkOFDMAUplinkSC-FDMADL Spectral Efficiency11.57 bps/Hz/Sector (2x2) MIMO21.59 bps/Hz/Sector (2x2) MIMOUL Spectral Efficiency10.64 bps/Hz/Sector (1x2) SIMO20.99 bps/Hz/Sector (1x2) SIMOMobility SupportTarget: Up to 350 km/hrUp to 120 km/hrFrame Size1 millisec5 millisecHARQIncremental RedundancyChase CombiningLink BudgetTypically limited by Mobile DeviceAdvanced Antenna SupportDL: 2x2, 2x4, 4x2, 4x4 UL: 1x2, 1x4, 2x2, 2x41. Spectral efficiency is based on NGMN Alliance recommended evaluation methodology2. Reference for LTE Spectral Efficiency: Motorola website, “LTE in Depth”.
90 Key Features of LTE Multiple access scheme Downlink: OFDMA Uplink: Single Carrier FDMA (SC-FDMA)Adaptive modulation and codingDL modulations: QPSK, 16QAM, and 64QAMUL modulations: QPSK and 16QAMRel-6 Turbo code: Coding rate of 1/3, two 8-state constituent encoders, and a contention- free internal interleaver.Bandwidth scalability for efficient operation in differently sized allocated spectrum bandsPossible support for operating as single frequency network (SFN) to support MBMS
91 Key Features of LTE(contd.) Multiple Antenna (MIMO) technology for enhanced data rate and performance.ARQ within RLC sublayer and Hybrid ARQ within MAC sublayer.Power control and link adaptationImplicit support for interference coordinationSupport for both FDD and TDDChannel dependent scheduling & link adaptation for enhanced performance.Reduced radio-access-network nodes to reduce cost,protocol-related processing time & call set-up time
92 Key LTE radio access features Downlink: OFDMUplink: SC-FDMAAdvanced antenna solutionsDiversityBeam-formingMulti-layer transmission (MIMO)Spectrum flexibilityFlexible bandwidthNew and existing bandsDuplex flexibility: FDD and TDDSC-FDMAOFDMATX20 MHz1.4 MHz
93 LTE: Not a Simple 3G Upgrade LTE Represents a Major Upgrade from CDMA-Based HSPA (or EV-DO)No longer a “simple” SW upgrade:CDMA to OFDMA, represent different technologiesCircuit switched to IP e2e networkAlso requires new spectrum to take full advantage of wider channel BWs and …Requires dual-mode user devices for seamless internetwork connectivity
95 OFDMLTE uses OFDM for the downlink – that is, from the base station to the terminal. OFDM meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates. OFDM uses a large number of narrow sub-carriers for multi-carrier transmission. The basic LTE downlink physical resource can be seen as a time-frequency grid. In the frequency domain, the spacing between the subcarriers, Δf, is 15kHz. In addition, the OFDM symbol duration time is 1/Δf + cyclic prefix. The cyclic prefix is used to maintain orthogonality between the sub-carriers even for a time-dispersive radio channel. One resource element carries QPSK, 16QAM or 64QAM. With 64QAM, each resource element carries six bits. The OFDM symbols are grouped into resource blocks. The resource blocks have a total size of 180kHz in the frequency domain and 0.5ms in the time domain. Each 1ms Transmission Time Interval (TTI) consists of two slots (Tslot). In E-UTRA, downlink modulation schemes QPSK, 16QAM, and 64QAM are available.
96 SC-FDMAThe LTE uplink transmission scheme for FDD and TDD mode is based on SC-FDMA (Single Carrier Frequency Division Multiple Access). This is to compensate for a drawback with normal OFDM, which has a very high Peak to Average Power Ratio (PAPR). High PAPR requires expensive and inefficient power amplifiers with high requirements on linearity, which increases the cost of the terminal and also drains the battery faster. SC-FDMA solves this problem by grouping together the resource blocks in such a way that reduces the need for linearity, and so power consumption, in the power amplifier. A low PAPR also improves coverage and the cell-edge performance. Still, SC-FDMA signal processing has some similarities with OFDMA signal processing, so parameterization of downlink and uplink can be harmonized.
97 … FDMA OFDM Power Power Multiple orthogonal carriers Channel Frequency TDMA…TimeUser 1User 2User 3User 4User 5
98 OFDMA is more frequency efficient than FDMA FDMA vs. OFDMAOFDMA is more frequency efficient than FDMAEach station is assigned a set of subcarriers, eliminating frequency guard bands between usersChannelGuard bandFDMAOFDMA
99 WiMAX LTE Dynamic OFDMA Fixed OFDMA Power Time Frequency Frequency Frequency allocation per user is continuous vs. timeFrequency allocation per user is dynamically allocated vs. time slotsUser 1User 2User 3User 4User 5
100 LTE-Downlink (OFDM) Improved spectral efficiency Reduce ISI effect by multipathAgainst frequency selective fadingfrequency selective fading在正交分頻多工系統中，原來的寬頻通道被分割成N 個子通道，透過使用串列至並行轉換器，將資料送至各個子載波上，由於資料區間被拉長為原本的N倍，所以這些子載波有著較低的傳輸速率，當子通道數目足夠多時，每個子載波可以視具有平坦的通道頻率響應，進而可以有效的對抗頻率選擇性衰減通道所造成的失真
101 LTE Uplink (SC-FDMA)SC-FDMA is a new single carrier multiple access technique which has similar structure and performance to OFDMAA salient advantage of SC-FDMA over OFDM is low to Peak to Average Power Ratio (PAPR) :Increasing battery life
102 SDMA = Smart Antenna Technologies BeamformingUse multiple-antennas to spatially shape the beam to improve coverage and capacitySpatial Multiplexing (SM) or Collaborative MIMOMultiple streams are transmitted over multiple antennasMulti-antenna receivers separate the streams to achieve higher throughputIn uplink single-antenna stations can transmit simultaneouslySpace-Time Code (STC)Transmit diversity such as Alamouti code [1,2] reduces fading2x2 Collaborative MIMO increases the peak data rate two-fold by transmitting two data streams.
103 Multiple Antenna Techniques MIMO employs multiple transmit and receive antennas to substantially enhance the air interface. It uses spacetime coding of the same data stream mapped onto multiple transmit antennas, which is an improvement over traditional reception diversity schemes where only a single transmit antenna is deployed to extend the coverage of the cell. MIMO processing also exploits spatial multiplexing, allowing different data streams to be transmitted simultaneously from the different transmit antennas, to increase the end-user data rate and cell capacity. In addition, when knowledge of the radio channel is available at the transmitter (e.g. via feedback information from the receiver), MIMO can also implement beam-forming to further increase available data rates and spectrum efficiency
104 Advanced Antenna Techniques Single data stream / userBeam-formingCoverage, longer battery lifeSpatial Division Multiple Access (SDMA)Multiple users in same radio resourceMultiple data stream / user DiversityLink robustnessSpatial multiplexingSpectral efficiency, high data rate supportBeamforming increases the user data rates by focusing the transmit power in the direction of the user, effectively increasing the signal at the user. Beamforming provides the most benefits to the users in areas with weaker signal strength, like the edge of the cell coverage.SDMA is another advanced technique, which increases sector capacity by allowing simultaneous transmissions of the same physical resources to different users, who are spatially separated. This technique can be combined with MIMO to offer higher data rates simultaneously.
105 Beamforming & SDMAEnhances signal reception through directional array gain, while individual antenna has omni-directional gain • Extends cell coverage • Suppresses interference in space domain • Enhances system capacity • Prolongs battery life • Provides angular information for user trackingSource: Key Features and Technologies in 3G Evolution, /sessionspeaker /file/atdownload
106 LTE spectrum (bandwidth and duplex) flexibility
107 Evolution of LTE-Advanced Asymmetric transmission bandwidthLayered OFDMAAdvanced Multi-cell Transmission/Reception TechniquesEnhanced Multi-antenna Transmission TechniquesSupport of Larger Bandwidth in LTE-Advanced
108 Asymmetric transmission bandwidth voice transmission : UE to UEAsymmetric transmissionstreaming video : the server to the UE (the downlink)
109 Layered OFDMA The bandwidth of basic frequency block is, 15–20 MHz Layered OFDMA radio access scheme in LTE-A will have layered transmission bandwidth, support of layered environments and control signal formats
110 Advanced Multi-cell Transmission/Reception Techniques In LTE-A, the advanced multi-cell transmission/reception processes helps in increasing frequency efficiency and cell edge user throughputEstimation unitCalculation unitDetermination unitFeedback unit
111 Enhanced Multi-antenna Transmission Techniques In LTE-A, the MIMO scheme has to be further improved in the area of spectrum efficiency, average cell through put and cell edge performancesIn LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned
112 Enhanced Techniques to Extend Coverage Area Remote Radio Requirements (RREs) using optical fiber should be used in LTE-A as effective technique to extend cell coverage
113 Support of Larger Bandwidth in LTE-Advanced Peak data rates up to 1Gbps are expected from bandwidths of 100MHz. OFDM adds additional sub-carrier to increase bandwidth
115 LTE Network Architecture The LTE architecture consists of E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) on the access side and EPC (Evolved Packet Core) on the core side.A typical LTE/SAE network will have two types of network elements.The first is the new enhanced base station, so called “Evolved NodeB (eNodeB)” per 3GPP standards. This enhanced BTS provides the LTE air interface and performs radio resource management for the evolved access system.The second is the new Access Gateway (AGW). The AGW provides termination of the LTE bearer. It also acts as a mobility anchor point for the user plane. It implements key logical functions including MME (Mobility Management Entity) for the Control Plane and for the User Plane. These functions may be split into separate physical nodes, depending on the vendor-specific implementation.[Source:Technical Overview of 3GPP Long Term Evolution (LTE) Hyung G. Myung
116 System Architecture Evolution(SAE) System Architecture Evolution (aka SAE) is the core network architecture of 3GPP's future LTE wireless communication standard.SAE is the evolution of the GPRS Core Network, with some differences.The main principles and objectives of the LTE-SAE architecture include :A common anchor point and gateway (GW) node for all access technologiesIP-based protocols on all interfaces;Simplified network architectureAll IP networkAll services are via Packet Switched domainSupport mobility between heterogeneous RATs, including legacy systems as GPRS, but also non-3GPP systems (say WiMAX)Support for multiple, heterogeneous RATs, including legacy systems as GPRS, but also non-3GPP systems (say WiMAX)RAT – Radio Access Technology
117 SAES1: provides access to Evolved RAN radio resources for the transport of user plane and control plane traffic. The S1 reference point enables MME and UPE separation and also deployments of a combined MME and UPES2: mobility support between WLAN 3GPP IP access or non 3GPP IP access and Inter AS AnchorS3: Enables user and bearer information exchange for inter 3GPP access systemS4 : Mobility support between GPRS Core and Inter AS AnchorS5a: Provides the user plane with related control and mobility support between MME/UPE and 3GPP anchor.S6: Provides transfer of subscription and authentication data for user access to the evolved system .S7: provides transfer of (QoS) policy and charging rules from PCRF (Policy and Charging Rule Function ) to Policy and Charging Enforcement Function (PCEF)GERAN-GSM EDGE Radio Access NetworkUTRAN-UMTS Terrestrial Radio Access NetworkSGSN Serving GPRS Support Node[Source:http://www.3gpp.org/Highlights/LTE/LTE.htm]
118 Evolved Packet Core (EPC) MME (Mobility Management Entity): -Manages and stores the UE control plane context, generates temporary Id, provides UE authentication, authorization, mobility management UPE (User Plane Entity): -Manages and stores UE context, ciphering, mobility anchor, packet routing and forwarding, initiation of paging 3GPP anchor: -Mobility anchor between 2G/3G and LTE SAE anchor: -Mobility anchor between 3GPP and non 3GPP (I-WLAN, etc)
119 LTE and WiMAX Modulation and Access CDMA (code division multiple access) is a coding and access schemeCDMA, W-CDMA, CDMA-2000SDMA (space division multiple access) is an access schemeMIMO, beamforming, sectorized antennasTDMA (time division multiple access) is an access schemeAMPS, GSMFDMA (frequency division multiple access) is an access schemeOFDM (orthogonal frequency division multiplexing) is a modulation schemeOFDMA (orthogonal frequency division multiple access) is a modulation and access scheme
120 3G W-CDMA Architecture 4G LTE Architecture Data Core (SGSN/GGSN) Iub interfaceIu PS interfaceATM/IPIu CS interfaceVoice Core(MSC)Iub interfaceATM/IP4G LTE ArchitectureIPMajor changes:IP interfaces mandatoryFewer nodes.X2 interface between base stations.Point to multipoint network connections.Lower latencyS1 interfaceX2 interfaceEvolvedPacket CoreIPS1 interface
121 Session 3: Fujitsu Packet Optical Solutions Technology Options For Connection-Oriented Ethernet (COE) Significant Differences Among Number of Layers to Manage4/20/2017RoutedNon-RoutedStaticPW/MPLST-MPLSMPLS-TPPBB-TEVLAN TagSwitchingIP/MPLSIP/MPLS-Based COEIS-IS, OSPF, BGP, IP addressing, BFDPWMPLS-TP LSPEthBFD, Protection ProtocolBFD, VCCV802.1ag, 802.3ah, Y.1731MPLS-TP-based COEMPLS LSPPWPWEthernet-based COEEthernet+PW+LSPEthEthEthernet+PW+LSPS-VLAN or PBB-TE TunnelBFD, RSVP-TE/LDP, FRREthEthernetEthT-LDP/BFD, VCCVG.8031, 802.1ag, 802.3ah, Y.1731802.1ag, 802.3ah, Y.1731(3) Data Plane LayersEthernetPseudowire (PW)LSP(1) Control Plane LayerIP(3) Data Plane LayersEthernetPseudowire (PW)LSP(1) Data Plane LayerEthernetKey messagesLTE service layer is IP. Backhaul network need not be service awareCOE is ideally suited to meet backhaul network’s stringent QoS and high availability requirementsWhile taking advantage of Ethernet’s statistical multiplexing and higher BW capabilitiesMPLS-TP is similar philosophically as the Ethernet-centric approach but adds addition data encapsulation layersCircuit emulation not neccessary for LTEBackhaul network is a key area to reduce OpExOpEx reduction is key to maintain or improve margins due to flat rate data service plansEthernet-based COE simplifies OAM&POnly 1 Layer to manage: Ethernet
122 Proposed LTE Architecture Example 3Backhaul for LTEEVPL for S1 interfaceE-LAN for X2 interfaceRAN BSCarrier Ethernet Aggregation NetworkRAN NCCarrier Ethernet Access NetworkRAN BSUNIENNIUNIUNIRAN BSEVPL 1ENNIEVPL 2EVPL 3EVPLANCarrier Ethernet Access Network
123 L2/L3 Backhaul Challenges Wholesale backhaul providers typically prefer L2:Simpler to provisionScalable BW “pipes” for unpredictable needsStrong Ethernet OAM mechanisms offer SLASub 50ms failover with 802.3ad and G.8032Pseudowire helps support 2G/3G services, in addition to LTEPowerful diagnostic tools“Pure-Play” wireless operators typically prefer L2:Simple / automatic provisioningEthernet circuit validation, PM, fault detection and analysisTraffic engineering oversubscribe link bandwidthIntegrated carriers may prefer L3 (skill sets)Mesh, alternate routing, but less developed OAM
124 Evolution From Sonet To Packet-Based Ethernet MBH Session 3: Fujitsu Packet Optical Solutions4/20/2017FMO Step 1:Add COE over Sonet to increase bandwidth efficiencyFMO Step 2:Begin Migration to EoF packet network.Existing services unaffectedPMO: SonetMSPPPacket Optical NetworkingPacket Optical NetworkingSonetSonetSonetEoFTDMEoSTDMCOETDMCOEDS1sEthernetDS1sEthernetDS1sEthernet2G/3G2G/3GLTE2G/3G3G/LTEPacket-optical networking platform with COE facilitatesMBH network migration of multi-generation 2G/3G/LTE services
125 LTE Backhaul Requirements (…and the radio perspective) DetailsHigh CapacitiesMbit/s per sitePeak rate & average173 Mbit/s vs. 35 Mbit/sLow latency<10msecHandover interface (X2)E-LAN for eNBs CommunicationEnhanced servicesService-aware networksDeployment paradigmsHotspot the size of a city/rural BBMigration strategiesTDM Ethernet 2G3GLTESynchronizationE1/T1 for legacy. 1588V2 & SyncEConvergenceTrue multiplay operators
127 Security With Connection-Oriented Ethernet COE uses few protocols. IP & MPLS require manyThe more protocols used, MBH network is more susceptible to attacksManagement VLANs isolated from user trafficSimilar to DCC isolation from user traffic in Sonet networksCOE has many security advantages over bridged solutionsCOE disables MAC address learning / floodingMAC address spoofing cannot occurMAC table overflow DOS attacks cannot occurCOE disables vulnerable Layer 2 control protocols (L2CPs)Protocol-based DOS attacks cannot occurCOE is immune to IP-based attacks & popular L2-based attacks
128 2G/3G/4G Backhaul Services over Ethernet/IP/MPLS Mobile Operator E2E T1 & Ethernet DiagnosticsMSCCT3/OC34G G/WMobileOperator AGigEE2E SLA Monitoring and DiagnosticsTest Equip.4G eNBTransport ProviderETH2G/3GFixedWirelessT1/E14G eNBWholesale Carrier EthernetMPLSETH2G/3GT1/E1MobileOperator BTest Equip.4G eNBCT3/OC3EthernetAccess Ring (50ms)2G/3GMSCETHT1/E14G G/WGigEPortalNMSData VLANs – Carry BH traffic, OAM and test data.Mgt VLAN – Management and SLA statistics
131 Satellite Broadband Wireless Use of satellites for personal wireless communication is fairly recentSatellite use falls into three broad categoriesSatellites are used to acquire scientific data and perform research in spaceSatellites look at Earth from spaceSatellites include devices that are simply reflectors
132 Satellite Technology Outlook Satellites can provide wireless communicationIn areas not covered by cellular or WiMAXSatellites today are enabling carriers to offerInternet access and voice calls to passengers and crews across large oceansAnd in high latitudes and remote corners of the EarthCan also make these services available in many other unpopulated areas
133 Satellite Broadband Wireless Rotate with the earth, usually over equator; 1/3 earth coverage
135 Satellite Transmissions Satellites generally send and receive on one of four frequency bandsFrequency band affects the size of the antennaL: GPSS: weather, NASA, Sirius/XM satellite radioC: open satellite communicationsKu: popular with remote locations transmitting back to TV studioKa: communications satellites
137 Satellite Transmissions (continued) Class and Type of ServiceSatellites can provide two classes of serviceConsumer class serviceShares the available bandwidth between the usersBusiness class serviceOffers dedicated channels with dedicated bandwidthTypes of connectivityPoint-to-point, point-to-multipoint, and multipoint-to-multipoint
140 Low Earth Orbit (LEO) Low earth orbit (LEO) satellites Circle the Earth at an altitude of 200 to 900 milesMust travel at high speedsSo that the Earth’s gravity will not pull them back into the atmosphereArea of Earth coverage (called the footprint) is smallLEO systems have a low latencyUse low-powered terrestrial devices (RF transmitters)Round trip time: 20 to 40 milliseconds
141 Orbits for typical LEO and MEO systems, e.g. GPS LEO and MEO satellites need to move or their orbits will decay;thus need >1 satellite to maintain connection.
142 LEO satellite systems UML: user mobile link GWL: gateway link ISL: intersatellite link
143 Low Earth Orbit (LEO) (continued) LEO satellites groupsBig LEOCarries voice and data broadband services, such as wireless Internet accessLittle LEOProvides pager, satellite telephone, and location services
144 LEO example: Iridium constellation Designed by Motorola during the 1990s, wentbankrupt in What cost $5 billion was soldfor $25 million.66 active satellites with a few spares at a heightof 781 km (485 miles).Sold to Iridium Communications Inc.Iridium plans to send up 66 new satellites and 6 sparesstarting in 2015, called IridiumNext. Data and voice.
145 Medium Earth Orbit (MEO) Medium earth orbit (MEO) satellitesOrbit the Earth at altitudes between 1,500 and 10,000 milesSome MEO satellites orbit in near-perfect circlesHave a constant altitude and constant speedOther MEO satellites revolve in elongated orbits called highly elliptical orbits (HEOs)AdvantagesMEO can circle the Earth in up to 12 hoursHave a bigger Earth footprint
147 Medium Earth Orbit (MEO) DisadvantageHigher orbit increases the latencyRound trip time: 50 to 150 millisecondsHEO satellitesHave a high apogee (maximum altitude) and a low perigee (minimum altitude)Can provide good coverage in extreme latitudesOrbits typically have a 24-hour period
148 MEO example: GPS (global positioning system) GPS was established in 1973 by U.S. andconsisted of 24 satellites (now ~32).Dual-use system – military and civilian. Civilianside used by commerce, science, banking, mobilephones, farmers, surveyors, power grids, you and me.GPS can provide absolute location, relative movement, andtime transfer.Inducted into Space Foundation Space Technology Hallof Fame in 1998.Three satellites gives you 2 points, but you can choose theone on the ground; 4 gives you 1 point and overcomes clockerrors; usually see at least 6; often see 8-10
149 MEO example: GPS (global positioning system) Each satellite continually transmits messagesthat include (1) the time the message wastransmitted, (2) precise orbital information (theephemeris), and (3) general system health andrough orbits of all GPS satellites (the almanac)Receiver takes messages, determines the transit time of eachmessage and computes the distances to each satellite.These distances along with satellites’ locations are usein determining receiver’s location (trilateration).(See Wikipedia GPS for cool image of satellite visibility.)
150 MEO example: GPS (global positioning system) GPS consists of 3 segments(1) Space segment – the space vehicles at ~20,200km(2) Control segment – a master control station, an alternatemaster control station, four dedicated ground antennas, andsix dedicated monitor stations(3) User segment – you and meAll satellites broadcast at two frequencies: GHz andGHz using CDMA spread-spectrum technologyWhat will you create?
151 Geosynchronous Earth Orbit (GEO) Geosynchronous earth orbit (GEO) satellitesStationed at an altitude of 22,282 milesOrbit matches the rotation of the EarthAnd moves as the Earth movesCan provide continuous service to a very large footprintThree GEO satellites are needed to cover the EarthHave high latencies of about 250 millisecondsRequire high-powered terrestrial sending devices
155 Example GEO satellite – Weather Weather satellites can watch more than weather. Can alsoobserve city lights, fires, pollution effects, auroras, sand anddust storms, snow cover, energy flows, volcano output, etc.Can observe both visible spectrum and infrared spectrumThe U.S. has two geostationary weather birds: GOES-11 andGOES GOES-12, or GOES-EAST, over the MississippiRiver, covers most of the U.S. weather. GOES-11 covers theeastern Pacific Ocean.