20-03-2012, 02:42 PM
Wireless Universal Serial Bus
WirelessUSB.ppt (Size: 1.14 MB / Downloads: 200)
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)
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
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 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