introduction to wireless cs 477. technologies tech. primary appl. data rates qos goals wlan: 802.11...
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Introduction to WirelessIntroduction to Wireless
CS 477CS 477
TechnologiesTechnologies
Tech.Tech. Primary Primary Appl.Appl.
Data RatesData Rates QoS GoalsQoS Goals
WLAN: WLAN: 802.11802.11
Wireless Wireless EthernetEthernet
Hot spot 11, Hot spot 11, 54 Mbps54 Mbps
Best Effort Best Effort ++
WLL:WLL:
LMDS/ LMDS/ MMDSMMDS
Wireless Wireless Cable: Cable: BusinessBusiness
50, 100, 50, 100, 150 Mbps150 Mbps
ATM classesATM classes
WPAN:WPAN:
BluetoothBluetoothTetherless Tetherless ComputingComputing
Master-Master-controlledcontrolled
CellularCellular Mobile Mobile Comm.Comm.
8, 144 kb/s 8, 144 kb/s - 2Mb/s- 2Mb/s
RT & Best RT & Best EffortEffort
Transmission TechniquesTransmission Techniques
Distributed/HierarchicalDistributed/Hierarchical
FDMA/TDMA/CDMAFDMA/TDMA/CDMA
TDD/FDDTDD/FDD
Network TypesNetwork Types
Distributed Network: Distributed Network: Users interface with Users interface with each othereach other• Ad Hoc Network: Self-Ad Hoc Network: Self-
creatingcreating
Hierarchical network: Hierarchical network: Users interface with Users interface with Base Station or Access Base Station or Access PointPoint• Polled: Master-SlavePolled: Master-Slave
MT MT
MT
BS
MT MT
MT MT
Hierarchical NetworksHierarchical Networks
Terminal Equipment
Base Station
DownlinkUplink
Time Division Duplex (TDD)Time Division Duplex (TDD)
Base Station & Terminal Equipment Base Station & Terminal Equipment alternate transmissionsalternate transmissions
Good when amount of downlink data Good when amount of downlink data > amount of uplink data> amount of uplink data
Frequency Division Multiple AccessFrequency Division Multiple AccessFrequency Division Duplex (FDD)Frequency Division Duplex (FDD)
Example: First Generation Cellular
Time Division Multiple AccessTime Division Multiple Access
TDMA - FDD
Time Division Multiple AccessTime Division Multiple Access
Channels allocated by Frequency & Channels allocated by Frequency & TimeslotTimeslot
A Multiframe defines who & what A Multiframe defines who & what transmits during a timeslot (E.g.:)transmits during a timeslot (E.g.:)• Broadcast / Paging / Synchronization Broadcast / Paging / Synchronization
ChannelChannel• Random Access ChannelRandom Access Channel• Signaling ChannelsSignaling Channels• Traffic ChannelTraffic Channel
Frequency Hopped Spread Frequency Hopped Spread Spectrum (FHSS)Spectrum (FHSS)
EDGE TechnologyEDGE Technology
EDGE TechnologyEDGE Technology
Finds Optimal Bit RateFinds Optimal Bit Rate• Selects modulation & coding scheme Selects modulation & coding scheme
based on environmentbased on environment • Uses Link Quality ControlUses Link Quality Control
Varies Modulation SchemeVaries Modulation Scheme• GMSK, 8-PSKGMSK, 8-PSK
Code Rate varies form .37 to 1.0Code Rate varies form .37 to 1.0
EDGE Modulation & CodingEDGE Modulation & Coding
MCS-9MCS-9 8PSK8PSK 11 59.2 kbps59.2 kbps
MCS-8MCS-8 8PSK8PSK 0.920.92 54.4 kbps54.4 kbps
MCS-7MCS-7 8PSK8PSK 0.760.76 44.8 kbps44.8 kbps
MCS-6MCS-6 8PSK8PSK 0.490.49 29.6 kbps29.6 kbps
MCS-5MCS-5 8PSK8PSK 0.370.37 22.4 kbps22.4 kbps
MCS-4MCS-4 GMSKGMSK 11 17.6 kbps17.6 kbps
MCS-3MCS-3 GMSKGMSK 0.850.85 14.8 kbps14.8 kbps
MCS-2MCS-2 GMSKGMSK 0.660.66 11.2 kbps11.2 kbps
MCS-1MCS-1 GMSKGMSK 0.530.53 8.8 kbps8.8 kbps
Direct Sequence Spread Spectrum Direct Sequence Spread Spectrum (DSSS)(DSSS)
1
1
1
1
1
1
1
1
0
00
0
0
0
00
Code Division Multiple Access Code Division Multiple Access (CDMA)(CDMA)
Each bit is transmitted multiple times Each bit is transmitted multiple times at different frequencies, called ...at different frequencies, called ...• Direct Sequence Spread SpectrumDirect Sequence Spread Spectrum• Fast Frequency HoppingFast Frequency Hopping
Message x spreading signalMessage x spreading signal• Pseudo-noise code sequence @ chip ratePseudo-noise code sequence @ chip rate• Codewords are orthogonal to each otherCodewords are orthogonal to each other
Interference LimitedInterference Limited
Multi-Carrier vs. Direct SequenceMulti-Carrier vs. Direct Sequence
Direct Sequence
Multi-Carrier
CDMA 2000 Technology
CDMA EnhancementsCDMA Enhancements
CDMA2000:CDMA2000: Chip rates of N=1, 3, 6, 9, 12Chip rates of N=1, 3, 6, 9, 12 Reduced spreadingReduced spreading Turbo codes: 10Turbo codes: 10-6 -6 vs 10vs 10-3-3
QPSK on Forward (v) Link QPSK on Forward (v) Link • BPSK on Reverse (^)BPSK on Reverse (^)
Spatial Diversity Multiple Spatial Diversity Multiple AccessAccess
SDMA or Smart AntennasSDMA or Smart Antennas• Forms a focused beamForms a focused beam• Allows channels to be reused within a cellAllows channels to be reused within a cell
Multibeam TypeMultibeam Type• Multiple fixed beams with a narrow focusMultiple fixed beams with a narrow focus
Adaptive Array Adaptive Array • Uses Spatial & Angle DiversityUses Spatial & Angle Diversity• Separates signal from its pathSeparates signal from its path
SDMASDMA
Varied Cell SizesVaried Cell Sizes
megacell macrocell microcell picocell
0 100 m 2 km 70 km 200-1000km
Diameter
Frequency AllocationsFrequency Allocations
Licensed: Cellular, Satellite, Licensed: Cellular, Satellite, WLLWLL
Unlicensed: WLAN, WPANUnlicensed: WLAN, WPAN
Licensed, Cellular FrequenciesLicensed, Cellular Frequencies
.824 - .894 US-DC, IS-95.890 - .960 ETACS / NMT / GSM
1.85-1.99 US-DC, IS-95
1.71-1.88 DCS 1800
1.92-2.17 UMTS - W-CDMA
Wireless CableWireless Cable
MMDS
LMDS
Frequency 2.1 & 2.5-2.686 GHz 27.5-28.35 GHz 31-31.3 GHz
Cell Size 25-35 miles 1-3 km
Wireless LAN / PANWireless LAN / PAN
IEEE 802.11BIEEE 802.11B
BLUETOOTHBLUETOOTH
Wireless LANWireless LAN
Unlicensed FrequenciesUnlicensed Frequencies Low Maximum Transmit PowerLow Maximum Transmit Power Possible Contention ProblemsPossible Contention Problems Frequencies Used:Frequencies Used:
• Industrial, Scientific, Manuf. (ISM): 2.4 GHzIndustrial, Scientific, Manuf. (ISM): 2.4 GHz• Unlicenced Nat. Info. Infrastructure (UNII): Unlicenced Nat. Info. Infrastructure (UNII):
5.2 GHz 300 MHz5.2 GHz 300 MHz 5.725 - 5.825 GHz5.725 - 5.825 GHz
IEEE 802.11BIEEE 802.11B
Header
192 us1 Mbps
Data: 1 of 4 rates Uses multiple subcarriers
Training Data
IEEE 802.11IEEE 802.11
Simultaneous Transmissions Possible HiddenTerminal
CSMA/CACSMA/CA
MT A MT B
RTS
MT C
CTS
ACK
Data
IEEE 802.11 ProtocolIEEE 802.11 Protocol
SIFS
PIFS
DIFS
IEEE 802.11 ProtocolIEEE 802.11 Protocol
Possible Simultaneous TXPossible Simultaneous TX CSMA/CACSMA/CA RTS/CTS notifies all in area of TXRTS/CTS notifies all in area of TX SIFS: Short delay before ack.SIFS: Short delay before ack. PIFS: Poll time-sensitive dataPIFS: Poll time-sensitive data
• Point Coordinator polls for high priorityPoint Coordinator polls for high priority DIFS: Anyone may contend to TXDIFS: Anyone may contend to TX
Bluetooth Personal Area Bluetooth Personal Area NetworkNetwork
Radio-based cable replacementRadio-based cable replacement• Low-cost, low-powerLow-cost, low-power• Created by IBM, Intel, Ericsson, Nokia, Created by IBM, Intel, Ericsson, Nokia,
Toshiba in Feb. ‘98Toshiba in Feb. ‘98• Joined by Motorola, Lucent, Microsoft, 3COMJoined by Motorola, Lucent, Microsoft, 3COM
FeaturesFeatures• Piconet: Swaps data at up to 10 metersPiconet: Swaps data at up to 10 meters• Data Rate: 721 kbps to 1 Mbps, or 3 Voice Data Rate: 721 kbps to 1 Mbps, or 3 Voice
@ 64 kbps@ 64 kbps
Bluetooth ApplicationsBluetooth Applications
Cordless desktop with peripheralsCordless desktop with peripherals Cordless phoneCordless phone LAN Access - Internet bridgeLAN Access - Internet bridge File Transfer: PDA synchronization File Transfer: PDA synchronization
with PCwith PC Headset / Intercom / Dial up networkHeadset / Intercom / Dial up network Home entertainment, lighting, Home entertainment, lighting,
securitysecurity
Bluetooth ProtocolBluetooth Protocol
IEEE 802.15 Standard defines layers IEEE 802.15 Standard defines layers 1 & 21 & 2
ISM Band: 2.4 GHz ISM Band: 2.4 GHz Spread spectrum: FHSSSpread spectrum: FHSS 1 Master polls up to 7 Slaves1 Master polls up to 7 Slaves Auto-initiation of updatesAuto-initiation of updates
Cellular SystemsCellular Systems
Functions of 2G NetworkFunctions of 2G Network
Cell SearchCell Search Location UpdateLocation Update Speech CallsSpeech Calls
• Mobile Originated CallMobile Originated Call• Paging: Mobile Terminated CallPaging: Mobile Terminated Call
HandoverHandover• Hard HandoverHard Handover• Soft HandoverSoft Handover
Short Message ServiceShort Message Service
Features of 3G CellularFeatures of 3G Cellular
Bit rates to 2 MbpsBit rates to 2 Mbps Variable Bit RateVariable Bit Rate Multiple services multiplexed on single Multiple services multiplexed on single
connection: voice, video, packet dataconnection: voice, video, packet data Real time and Best Effort trafficReal time and Best Effort traffic FER: 10% to 10FER: 10% to 10-6-6
Handovers between 2G & 3G systemsHandovers between 2G & 3G systems Asymmetric uplink and downlinkAsymmetric uplink and downlink
ServicesServicesClass of Class of ServiceService
CharacteristicsCharacteristics ApplicationsApplications
ConversationalConversational Delay-Delay-sensitive, sensitive, SymmetricSymmetric
Voice, Voice, videotelephonyvideotelephony
StreamingStreaming Constant delay, Constant delay, AsymmetricAsymmetric
Multimedia, Multimedia, web broadcastweb broadcast
InteractiveInteractive Request/ Request/ ResponseResponse
Web browsing, Web browsing, network gamesnetwork games
BackgroundBackground Delay-Delay-insensitiveinsensitive
EmailEmail
Network ArchitectureNetwork Architecture
Universal Mobile Universal Mobile Telecommunications System Telecommunications System
(UMTS)(UMTS)
VocabularyVocabulary
Control Plane:Control Plane: Radio Resource Radio Resource
ControlControl Mobility MgmtMobility Mgmt Call ControlCall Control
User Plane:User Plane: SpeechSpeech Circuit-Switched Circuit-Switched
DataData Packet-Switched Packet-Switched
DataData
High Level System ArchitectureHigh Level System Architecture
UserEquipment
(UE)
UMTSTerrestrial
RadioAccess
Network(UTRAN)
CoreNetwork
(CN)
Uu Iu
User EquipmentUser Equipment
UMTSTerrestrial
RadioAccess
Network(UTRAN)
CoreNetwork
(CN)
Uu Iu
MobileEquip.
USIMSubscriber
IdentityModule
Radio Interface ProtocolsRadio Interface Protocols
Physical Layer
Medium Access Control
Radio Link Control
Control Plane Protocols User Plane Protocols
Logical Channels
Transport Channels
Logical ChannelsLogical Channels
Control Channels:Control Channels: Broadcast Control (BCCH): Downlink Broadcast Control (BCCH): Downlink
broadcasts system information broadcasts system information Paging Control (PCCH): Downlink incoming Paging Control (PCCH): Downlink incoming
call info.call info. Dedicated Control (DCCH): Bidirectional Dedicated Control (DCCH): Bidirectional
control info (inside call)control info (inside call) Common Control (CCCH): Bidirectional Common Control (CCCH): Bidirectional
control info (outside call)control info (outside call)
Logical ChannelsLogical Channels
Traffic Channels:Traffic Channels: Dedicated Traffic (DTCH): Dedicated Traffic (DTCH):
Bidirectional point-to-point dedicated Bidirectional point-to-point dedicated channelchannel
Common Traffic (CTCH): Downlink Common Traffic (CTCH): Downlink point-to-multipoint channelpoint-to-multipoint channel
Radio Link ControlRadio Link Control
Layer 2:Layer 2: Transparent: No protocolTransparent: No protocol Unacknowledged ModeUnacknowledged Mode Acknowledged ModeAcknowledged Mode
UTRANUTRAN
CoreNetwork
(CN)
Uu Iu
MobileEquip.
USIMSubscriber
IdentityModule
Node B
RNCNode B
Node B
Node B
RNC
UTRAN ProtocolsUTRAN Protocols
Uses ATM base:Uses ATM base: ATM AAL5: ControlATM AAL5: Control ATM AAL2: SpeechATM AAL2: Speech RANAP: Radio Access Network RANAP: Radio Access Network
Application ProtocolApplication Protocol
Core NetworkCore Network
Uu Iu
MobileEquip.
USIMSubscriber
IdentityModule
Node B
RNCNode B
Node B
Node B
RNC
MSC/VLR
GMSC
SGSN GGSN
HLR
PSTN
Internet
Core Network NodesCore Network Nodes Circuit-Switched: Circuit-Switched:
• Mobile Switching Center (MSC): switches PCM Mobile Switching Center (MSC): switches PCM speechspeech
Packet-Switched:Packet-Switched:• Serving GPRS Support Node (SGSN) Serving GPRS Support Node (SGSN) • Gateway Support Node (GGSN): Interface to Gateway Support Node (GGSN): Interface to
global Internetglobal Internet CommonCommon
• Home Location Register (HLR): Permanent Home Location Register (HLR): Permanent source of subscription informationsource of subscription information
• Visitor Location Register (VLR): Local source for Visitor Location Register (VLR): Local source for user subscription optionsuser subscription options
GPRS Network ArchitectureGPRS Network ArchitectureServing GPRS Support Node (SGSN)Serving GPRS Support Node (SGSN)
• Interfaces with MS via BSInterfaces with MS via BS• Performs security, mobility / VLR functionsPerforms security, mobility / VLR functions
Gateway GPRS Support Node (GGSN)Gateway GPRS Support Node (GGSN)• Interfaces to InternetInterfaces to Internet• Learns MS location via HLRLearns MS location via HLR• Routes data to the SGSN using IPRoutes data to the SGSN using IP
Network is evolving as 3G/4G progressesNetwork is evolving as 3G/4G progresses
Physical Layer ChannelsPhysical Layer Channels
Common ChannelCommon Channel
Dedicated ChannelDedicated Channel
Shared ChannelShared Channel
Dedicated Transport ChannelDedicated Transport Channel
Circuit-switched services: speech, Circuit-switched services: speech, teleconferencingteleconferencing
Variable bit rateVariable bit rate• Fast data rate changeFast data rate change
Soft handoverSoft handover Physical channels:Physical channels:
• Dedicated Physical Data Channel: User dataDedicated Physical Data Channel: User data• Dedicated Physical Control Channel: Physical Dedicated Physical Control Channel: Physical
layer controllayer control
Common Transport ChannelsCommon Transport Channels
Broadcast: Downlink cell-specific Broadcast: Downlink cell-specific informationinformation
Forward Access: Downlink control & packet Forward Access: Downlink control & packet info.info.
Paging: Downlink data relevant to pagingPaging: Downlink data relevant to paging Random Access: Uplink request for serviceRandom Access: Uplink request for service Uplink Common Packet: Extended data Uplink Common Packet: Extended data
requestsrequests Downlink Shared: Shared for dedicated Downlink Shared: Shared for dedicated
data/controldata/control