27-07-2011, 04:26 PM
[attachment=14832]
Wireless Universal Serial Bus
Overview
Plug/Play standard for peripheral devices
Standardized by the USB Implementers Forum
Technical Details
Host/Slave Connection
PC (host) manages all transfers; peripherals (slave) just responds
Supports 127 slaves per host
Physical Connection
Four wire connection
Two wires for power (+5 and GND)
Two wires (twisted pair) for synchronous serial data
Computer supplies power (up to 500 mA)
Wired USB
Technical Details (Cont.)
Data Rates
Low 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 USB
Wired Issues
Wires are restrictive
Multiple wires can be a hassle
Wires slower than wireless solutions
Current wireless solutions inadequate
Bluetooth
Bandwidth of 3 Mbps not enough for higher demand applications (Video, HDTV, Monitor)
WiFi
Expensive
Too much power usage for mobile devices
Data Rate Comparisons
Wireless USB Overview
Overview
Has evolved as companies figured out standards
Based on Ultra-Wideband (UWB) RF technology
UWB 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 Code
1924: Spark Gap forbidden due to disruptive nature to narrowband carrier radios
1960s – 1999s: Better test equipment promoted research of UWB for radar and communications
Wireless USB Overview
History of Ultra-Wideband (cont.)
April 2002: FCC issued UWB Regulations
Permitted marketing and operation of new products
Limited power and freq range
2002: Two standards emerge
Orthogonal Frequency Division Multiplexing (OFDM) UWB
WiMedia Alliance & Intel
Direct Sequence (DS) UWB
UWB Forum & Freescale
2006: DS-UWB loses support & OFDM-UWB wins
Freescale left UWB Forum; became quiet
Many companies dropped Freescale chips
Freescale trying proprietary “Cable-Free USB”
2007: Products begin to hit the market
Wireless USB Overview
Goals of Intel OFDM-UWB Wireless USB Standard
Wireless version of USB; same features, speeds
Interoperable across three major platforms
Consumer 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 friendly
Low power usage
Inexpensive costs
Small physical implementation
High level of security
Next gen Wireless Personal Area Network (WPAN)
Wireless USB Vision
Wireless USB Vision
Wireless USB Physical Design
Features of UWB
Speed/Range
Scaleable speeds up over 1 Gbps
Currently 480 Mbps at 3 m; 110 Mbps at 10 m
Frequency: 3.1 GHz to 10.6 GHz
Divided into 14 bands; 5 groups
Each band is 528 MHz wide
OFDM symbols are interleaved across all bands
Provides protection against multi-path / interference
Wireless USB Physical Design
Features of UWB (cont.)
Frequency: 3.1 GHz to 10.6 GHz (cont.)
Band Groups 1 & 2: Longer range apps
Bands Groups 3 & 4: Shorter range apps
Bands can be turned off to accommodate for conflicts or for regulations
Wireless USB Physical Design
Features of UWB (cont.)
Power
Power is limited due to usage of wide spectrum
Low power for mobile devices and minimum interference
Max output to -41.3 dBm/MHz
Wireless USB Security Design
Overview
Strongly stressed in wUSB specification and outlined in its own requirements document
Security needed due to crowded environments
Two major components: Association and Encryption
Association
Overview
Device must first associate with the host in a one-time event
Accomplished via wired verification or numeric association
Wireless USB Security Design
Association (cont.)
Wired Verification
Cable is attached between devices
Exchanges a unique 384-bit identifier known as the “connection context”
Numeric Association
Devices associate wirelessly
User must enter a hex code manually
Wireless USB Security Design
Encryption
Data encrypted with the AES 128 algorithm
During each session devices derive a session key based on “connection context”
Wireless data is encrypted using session key
Does not encrypt PHY and MAC headers
Wireless USB Connection Design
Host/Slave Connection
Similar to wired USB (127 devices; host is PC)
Each host forms a cluster
Clusters can coexist with minimum interference
Power Management
Sleep/Listen/Wake
used to conserve
power
Tx/Rx power
management
Wireless USB Issues/Problems
Interference Issues
Potential conflict to devices on same frequencies
“Detect and Avoid”
Wisair’s solution to detect other frequencies
Switches to frequencies not being used
Conflict issues are more of a concern for wireless USB devices being overpowered
Competing Standards
Cable-Free USB (Freescale)
USB-Implementers Forum (Intel, HP, Microsoft)
Product Comparison
Wireless USB Implementations
Belkin Cable Free Hub
Released Dec, 2006
Dongle attaches to PC
Retail price of $199.00
Speeds up to 480 Mbps
Wireless USB Implementations
GeFen HMDI Extender
Coming soon…
Based on WiMedia Alliance specification
Retail price of $699.00
Range of 20 meters; data rates up to 480 Mbps
Frequency band: 3.1 - 4.8 GHz
Resolution support : 480i, 480p, 720p, and 1080i
Wireless USB Implementations
Seagate Wireless USB Hard Drive
Coming soon…
2.5 inches wide
Speeds up to 480 Mbps
Future of Wireless USB
Early 2007
Initial devices being produced
Late 2007
Expect wUSB being built into laptops, PCs, multimedia devices
2008
Visiongain research firm predicts increase of wUSB by 400 percent
2009-2010
Wide scale interoperability?
Concluding Thoughts
Appears well designed; good support
Slow start of products
Will it really catch on?
More products need to be developed
Promises a lot; will it deliver?
Security is very important
Wireless Universal Serial Bus
Overview
Plug/Play standard for peripheral devices
Standardized by the USB Implementers Forum
Technical Details
Host/Slave Connection
PC (host) manages all transfers; peripherals (slave) just responds
Supports 127 slaves per host
Physical Connection
Four wire connection
Two wires for power (+5 and GND)
Two wires (twisted pair) for synchronous serial data
Computer supplies power (up to 500 mA)
Wired USB
Technical Details (Cont.)
Data Rates
Low 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 USB
Wired Issues
Wires are restrictive
Multiple wires can be a hassle
Wires slower than wireless solutions
Current wireless solutions inadequate
Bluetooth
Bandwidth of 3 Mbps not enough for higher demand applications (Video, HDTV, Monitor)
WiFi
Expensive
Too much power usage for mobile devices
Data Rate Comparisons
Wireless USB Overview
Overview
Has evolved as companies figured out standards
Based on Ultra-Wideband (UWB) RF technology
UWB 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 Code
1924: Spark Gap forbidden due to disruptive nature to narrowband carrier radios
1960s – 1999s: Better test equipment promoted research of UWB for radar and communications
Wireless USB Overview
History of Ultra-Wideband (cont.)
April 2002: FCC issued UWB Regulations
Permitted marketing and operation of new products
Limited power and freq range
2002: Two standards emerge
Orthogonal Frequency Division Multiplexing (OFDM) UWB
WiMedia Alliance & Intel
Direct Sequence (DS) UWB
UWB Forum & Freescale
2006: DS-UWB loses support & OFDM-UWB wins
Freescale left UWB Forum; became quiet
Many companies dropped Freescale chips
Freescale trying proprietary “Cable-Free USB”
2007: Products begin to hit the market
Wireless USB Overview
Goals of Intel OFDM-UWB Wireless USB Standard
Wireless version of USB; same features, speeds
Interoperable across three major platforms
Consumer 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 friendly
Low power usage
Inexpensive costs
Small physical implementation
High level of security
Next gen Wireless Personal Area Network (WPAN)
Wireless USB Vision
Wireless USB Vision
Wireless USB Physical Design
Features of UWB
Speed/Range
Scaleable speeds up over 1 Gbps
Currently 480 Mbps at 3 m; 110 Mbps at 10 m
Frequency: 3.1 GHz to 10.6 GHz
Divided into 14 bands; 5 groups
Each band is 528 MHz wide
OFDM symbols are interleaved across all bands
Provides protection against multi-path / interference
Wireless USB Physical Design
Features of UWB (cont.)
Frequency: 3.1 GHz to 10.6 GHz (cont.)
Band Groups 1 & 2: Longer range apps
Bands Groups 3 & 4: Shorter range apps
Bands can be turned off to accommodate for conflicts or for regulations
Wireless USB Physical Design
Features of UWB (cont.)
Power
Power is limited due to usage of wide spectrum
Low power for mobile devices and minimum interference
Max output to -41.3 dBm/MHz
Wireless USB Security Design
Overview
Strongly stressed in wUSB specification and outlined in its own requirements document
Security needed due to crowded environments
Two major components: Association and Encryption
Association
Overview
Device must first associate with the host in a one-time event
Accomplished via wired verification or numeric association
Wireless USB Security Design
Association (cont.)
Wired Verification
Cable is attached between devices
Exchanges a unique 384-bit identifier known as the “connection context”
Numeric Association
Devices associate wirelessly
User must enter a hex code manually
Wireless USB Security Design
Encryption
Data encrypted with the AES 128 algorithm
During each session devices derive a session key based on “connection context”
Wireless data is encrypted using session key
Does not encrypt PHY and MAC headers
Wireless USB Connection Design
Host/Slave Connection
Similar to wired USB (127 devices; host is PC)
Each host forms a cluster
Clusters can coexist with minimum interference
Power Management
Sleep/Listen/Wake
used to conserve
power
Tx/Rx power
management
Wireless USB Issues/Problems
Interference Issues
Potential conflict to devices on same frequencies
“Detect and Avoid”
Wisair’s solution to detect other frequencies
Switches to frequencies not being used
Conflict issues are more of a concern for wireless USB devices being overpowered
Competing Standards
Cable-Free USB (Freescale)
USB-Implementers Forum (Intel, HP, Microsoft)
Product Comparison
Wireless USB Implementations
Belkin Cable Free Hub
Released Dec, 2006
Dongle attaches to PC
Retail price of $199.00
Speeds up to 480 Mbps
Wireless USB Implementations
GeFen HMDI Extender
Coming soon…
Based on WiMedia Alliance specification
Retail price of $699.00
Range of 20 meters; data rates up to 480 Mbps
Frequency band: 3.1 - 4.8 GHz
Resolution support : 480i, 480p, 720p, and 1080i
Wireless USB Implementations
Seagate Wireless USB Hard Drive
Coming soon…
2.5 inches wide
Speeds up to 480 Mbps
Future of Wireless USB
Early 2007
Initial devices being produced
Late 2007
Expect wUSB being built into laptops, PCs, multimedia devices
2008
Visiongain research firm predicts increase of wUSB by 400 percent
2009-2010
Wide scale interoperability?
Concluding Thoughts
Appears well designed; good support
Slow start of products
Will it really catch on?
More products need to be developed
Promises a lot; will it deliver?
Security is very important
