wireless usb

Wireless Universal Serial Bus: 

Wireless Universal Serial Bus KOTA PURNACHANDU SRI HARSHA INSTUITE OF PG STUDIES NELLORE

Outline: 

Outline Wired Universal Serial Bus (USB) Overview of Wireless USB (wUSB) History/Vision Features How wUSB Works Design Security Issues/Limitations Current Implementations Future/Conclusion

Wired USB: 

Wired USB 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: 

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: 

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: 

Data Rate Comparisons

Wireless USB Overview: 

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: 

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: 

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 Vision: 

Wireless USB Vision

Wireless USB Physical Design: 

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: 

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: 

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: 

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: 

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: 

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: 

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: 

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: 

Product Comparison

Wireless USB Implementations: 

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: 

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: 

Wireless USB Implementations Seagate Wireless USB Hard Drive Coming soon… 2.5 inches wide Speeds up to 480 Mbps

Future of Wireless USB: 

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: 

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

Slide 26: 

Questions?