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Jim ChoateSenior HW Engineer
Intel Corporation
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AgendaAgenda
• Intro to UWB radios• WUSB MAC-PHY Interface• Integration/prototype developmentand testing
• Hardware design guidelines• Antennas• Summary
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Intro to UWB RadiosIntro to UWB Radios
• What is UWB• Frequency of wireless technologies • Relative power of various wireless
technologies• Band Group 1
•Sub-bands for initial implementationof WUSB
• UWB scope demonstration
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What is UWBWhat is UWB
• UWB, Ultra-Wideband (Signal with 528 MHz of BW)
• Underlay, Transmission that looks like noise to most narrow band transmitters and receivers
• OFDM Radio, Orthogonal Frequency Division Multiplexing
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Where Does UWB Fit InWhere Does UWB Fit In
UWB
• Up to 480Mbps
• WPAN range
WUSB
1 Mbps
10 Mbps
55 Mbps
1 Gbps
100 Mbps
Bluetooth, ZigbeeLow speed WPANs
480 Mbps
Next Gen802.11n
3G
802.11b
802.16
4G
802.11a/g
2.5G/2G
WPAN WLAN WWAN
Desktop Room Building Community<1m 10m 100m Km(s)
UWB Fills the Gap in the Bandwidth vs. Distance PlaneUWB Fills the Gap in the Bandwidth vs. Distance Plane
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Frequency Range of UWBFrequency Range of UWB
Band Group #1, WUSB
Ongoing development
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Relative Transmit PowerRelative Transmit Power
WUSB
Band Group #1
Frequency (Ghz)
1.6 2 3.12.4 5 10.6
GPS
Bluetooth,802.11b/gCordless Phones,Microwave ovens 802.11aPCS
UWB Spectrum
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Band Group #1Band Group #1
Band Group #1
Band #1 Band #2 Band #3
3432MHz
3960MHz
4488MHz
Each Band = 528Mhz
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Band #1 Band #2 Band #3
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WUSB Scope DemonstrationWUSB Scope Demonstration
Demo
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WUSB MAC-PHY InterfaceWUSB MAC-PHY Interface
• MAC-PHY interface• WiMedia (MBOA) MAC-PHY Interface specification• Current revision at 0.95• Defines logical and timing interface
• MAC-PHY Mechanical Interface specification for prototyping and integration/testing needed
• Should provide power to PHY• Need readily available connector• Should support cabling option• Needs to make strong physical connection
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Prototyping MAC-PHYConnector ProposalPrototyping MAC-PHYConnector Proposal
• Use a standard 2x20 stake pin (IDE style) connector• PHY uses standard IDE male connector• MAC uses 2x20 receptacle connector
• Can use 80-conductor Ultra ATA cablefor cabled solutions
• Cables readily available• Convenient LA probing
• Connectors readily available• Minimal layout and routing constraints• Multiple MAC and PHY vendors implementing this
interface for early prototype development
Refer to the WUSB MAC-PHY prototype interface specification for details. Refer to the WUSB MAC-PHY prototype interface specification for details.
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Ground40RSVD239
Ground38RSVD137
Ground36STOPC35
Ground34SER DAT33
Ground32CCA ST31
Ground30DATAEN29
NC28PHYACT27
Ground26RXEN25
Ground24TXEN23
Ground22PCLK21
Key20Ground19
NC18Data 717
PWR (3.3VDC)16Data 615
PWR (3.3VDC)14Data 513
PWR (3.3VDC)12Data 411
PWR (3.3VDC)10Data 39
PWR (3.3VDC)8Data 27
PWR (3.3VDC)6Data 15
NC4Data 03
Ground2Reset1
functionPinFunctionPin
40 Pin PDK Connector Pin-Out
2x20 MAC2x20 MAC--PHYPHYPDK Connector PDK Connector
PinPin--outout
MAC Connector
PHY Connector
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WUSB PDKWUSB PDK
• 33 MHz PCIInterface
• Altera Excalibur FPGA
• ARM CPU
• 128MB SDRAM• 32MB Flash• UART
PDK Top ViewPDK Top View 40 pin 2x20 connector
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Hardware Design ConsiderationsHardware Design Considerations
• WUSB presents new challenges• Board routing, placement• EMI/EMC requirements• MAC-PHY interface testing/compatibility• RF testing• RF isolation• Antenna placement/connection considerations
• USB-IF Will Provide Design GuidesIn Such Areas
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General Routing GuidelinesGeneral Routing Guidelines
D-DD--
15k15kΩΩ
• Control trace widths to obtain target impedance• Ask your board vendor what they can achieve• As always, cost is a consideration
• Maintain strict trace spacing control• Minimize stubs
D+D+D+15k15kΩΩ
Correct way to connect to resistorsCorrect way to connect to resistors7
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Routing GuidelinesRouting Guidelines
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• Routing over plane splits• Creating stubs with test points• Violating trace spacing guidelines
Common Routing Mistakes
Ground or power planeGround or power plane
tptpDon’t crossplane splitsDon’t crossplane splits
Proper routing technique maintains spacing guidelines
Proper routing technique maintains spacing guidelines
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DWA Design ConsiderationsDWA Design Considerations
DWA USB DeviceUSB cable External
Dongle
Compelling choice for existing USB products
DWA USB DeviceUSBUSB Internal PCB or
Daughterboard
Association model used will effect HWdesign choices
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RF TestingRF Testing
• Transmitter test challenges• What do I need to test?
• Transmitter power• Power mask• Pulse shape• Error Vector Magnitude (EVM)• MBOA PHY specification compliance
(PHY interoperability)• Others?
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Antenna Placement ConsiderationsAntenna Placement Considerations
• Product type will effect Antenna placement options
• Example: desktop PC vs Mobile PC
• Antenna distance and interconnect type to AFE is critical
• Proximity to noise sources and other RF sources is key consideration
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UWB AntennasUWB Antennas
How Big IS a UWB Antenna?
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UWB AntennasUWB Antennas
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Antenna Design ConsiderationsAntenna Design Considerations
• Common terms used in antenna specs• VSWR• Radiation Pattern• Antenna Gain• Frequency Range• Polarization• Impedance• Filters
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Antenna TerminologyAntenna Terminology
Real Dipole
• VSWR – Voltage standing wave ratio• Antenna Gain
• Decibels (dB) = 10*log(Pout/Pin)• dBi (relative to isotropic)• dBD (relative to Dipole)
f3432MHz
3960MHz
4488MHz
3 4 5
Relatively Good VSWR Relatively Bad VSWR
123456
Ideal
Ideal Dipole
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Antenna TerminologyAntenna Terminology
• Operating frequency (3.1-5.2GHz)• Polarization
• Linear (vertical and horizontal)
• Impedance• Typically 50 ohms• Requires BALUN (BALanced – Unbalanced)
• Filters• Band pass• Notch filter (for example 802.11a)
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SummarySummary
• WUSB uses UWB radios (3.1 – 10.6 GHz)• Band Group #1
• WUSB HW design presents new challenges• Understanding UWB technology advantages and limitations• Board Layout and Routing• Antenna Selection• Antenna Placement• RF Testing• MAC and PHY Interoperability
• The USB-IF will provide Design Guides In Such Areas
