Wireless Universal Serial BusName :- Rajveer singhCourse :-B.Tech 6th sem

OutlineWired Universal Serial Bus (USB)Overview of Wireless USB (wUSB)History/VisionFeaturesHow wUSB WorksDesignSecurityIssues/LimitationsCurrent ImplementationsFuture/Conclusion

Wired USBOverviewPlug/Play standard for peripheral devicesStandardized by the USB Implementers ForumTechnical DetailsHost/Slave ConnectionPC (host) manages all transfers; peripherals (slave) just respondsSupports 127 slaves per hostPhysical ConnectionFour wire connectionTwo wires for power (+5 and GND)Two wires (twisted pair) for synchronous serial dataComputer supplies power (up to 500 mA)

Wired USBTechnical Details (Cont.)Data RatesLow Speed: 1.5 Mbps (Keyboards, mice, etc.)Full Speed: 12 Mbps (USB1.1 max speed)Hi-Speed: 480 Mbps (USB2.0 max speed)

Reasons For Wireless USBWired IssuesWires are restrictiveMultiple wires can be a hassleWires slower than wireless solutionsCurrent wireless solutions inadequateBluetoothBandwidth of 3 Mbps not enough for higher demand applications (Video, HDTV, Monitor)WiFiExpensiveToo much power usage for mobile devices

Data Rate Comparisons

Wireless USB OverviewOverviewHas evolved as companies figured out standardsBased on Ultra-Wideband (UWB) RF technologyUWB is a technology for transmitting data over a large bandwidth (>500 MHz)History of Ultra-Wideband (UWB)Late 1800s: Started with Spark Gap radio for transmitting Morse Code1924: Spark Gap forbidden due to disruptive nature to narrowband carrier radios1960s 1999s: Better test equipment promoted research of UWB for radar and communications

Wireless USB OverviewHistory of Ultra-Wideband (cont.)April 2002: FCC issued UWB RegulationsPermitted marketing and operation of new productsLimited power and freq range2002: Two standards emergeOrthogonal Frequency Division Multiplexing (OFDM) UWBWiMedia Alliance & IntelDirect Sequence (DS) UWBUWB Forum & Freescale2006: DS-UWB loses support & OFDM-UWB winsFreescale left UWB Forum; became quietMany companies dropped Freescale chipsFreescale trying proprietary Cable-Free USB 2007: Products begin to hit the market

Wireless USB OverviewGoals of Intel (Orthogonal frequency-division multiplexing) OFDM-UWB Wireless USB Standard OFDM - scheme used as a digital multicarrier modulation method

Wireless version of USB; same features, speedsInteroperable across three major platformsConsumer Electronic devices (digital video/audio)Mobile devices (cellular phones, PDA)Personal Computing (laptop, PC, printer, peripherals)High bandwidth to support demanding data transfer (High Definition, Monitors)Mobile friendlyLow power usageInexpensive costsSmall physical implementationHigh level of securityNext gen Wireless Personal Area Network (WPAN)

Wireless USB Vision

Wireless USB Physical DesignFeatures of UWBSpeed/RangeScaleable speeds up over 1 GbpsCurrently 480 Mbps at 3 m; 110 Mbps at 10 mFrequency: 3.1 GHz to 10.6 GHzDivided into 14 bands; 5 groupsEach band is 528 MHz wideOFDM symbols are interleaved across all bandsProvides protection against multi-path / interference

Wireless USB Physical DesignFeatures of UWB (cont.)Frequency: 3.1 GHz to 10.6 GHz (cont.)Band Groups 1 & 2: Longer range appsBands Groups 3 & 4: Shorter range appsBands can be turned off to accommodate for conflicts or for regulations

Wireless USB Physical DesignFeatures of UWB (cont.)PowerPower is limited due to usage of wide spectrumLow power for mobile devices and minimum interferenceMax output to -41.3 dBm/MHz

Wireless USB Security DesignOverviewStrongly stressed in wUSB specification and outlined in its own requirements documentSecurity needed due to crowded environmentsTwo major components: Association and EncryptionAssociationOverviewDevice must first associate with the host in a one-time eventAccomplished via wired verification or numeric association

Wireless USB Security DesignAssociation (cont.)Wired VerificationCable is attached between devicesExchanges a unique 384-bit identifier known as the connection contextNumeric AssociationDevices associate wirelesslyUser must enter a hex code manually

Wireless USB Security DesignEncryptionData encrypted with the AES 128 algorithmDuring each session devices derive a session key based on connection contextWireless data is encrypted using session keyDoes not encrypt PHY and MAC headers

Wireless USB Connection DesignHost/Slave ConnectionSimilar to wired USB (127 devices; host is PC)Each host forms a clusterClusters can coexist with minimum interferencePower ManagementSleep/Listen/Wakeused to conservepowerTx/Rx powermanagement

Wireless USB Issues/ProblemsInterference IssuesPotential conflict to devices on same frequenciesDetect and AvoidWisairs solution to detect other frequenciesSwitches to frequencies not being usedConflict issues are more of a concern for wireless USB devices being overpoweredCompeting StandardsCable-Free USB (Freescale)USB-Implementers Forum (Intel, HP, Microsoft)

Product Comparison

Wireless USB ImplementationsBelkin Cable Free HubReleased Dec, 2006Dongle attaches to PCRetail price of $199.00Speeds up to 480 Mbps

Wireless USB ImplementationsGeFen HMDI ExtenderComing soonBased on WiMedia Alliance specificationRetail price of $699.00Range of 20 meters; data rates up to 480 MbpsFrequency band: 3.1 - 4.8 GHz Resolution support : 480i, 480p, 720p, and 1080i

Wireless USB ImplementationsSeagate Wireless USB Hard DriveComing soon2.5 inches wideSpeeds up to 480 Mbps

Future of Wireless USBEarly 2007Initial devices being producedLate 2007Expect wUSB being built into laptops, PCs, multimedia devices2008Visiongain research firm predicts increase of wUSB by 400 percent2009-2010Wide scale interoperability?

Concluding ThoughtsAppears well designed; good supportSlow start of productsWill it really catch on?More products need to be developedPromises a lot; will it deliver?Security is very important

Questions?