Alan Freedman -- The Computer Language Company - Computer Desktop Encyclopedia
Computer Desktop Encyclopedia
Longest-Running Tech Reference on the Planet

A CDE Definition

You'll love The Computer Desktop Encyclopedia (CDE) for Tech Term of the Day (TTOD)


Passive Wi-Fi

A Wi-Fi technology developed by the University of Washington for low-power sensors and mobile devices. Passive Wi-Fi is said to use 10,000 times less power than regular Wi-Fi and 1,000 times less than Bluetooth LE (Low Energy) and ZigBee.

A Shared RF Signal
When a device transmits a Wi-Fi signal, its digital baseband processor modulates the carrier frequency using tens of microwatts of power. However, the analog RF chip that generates the carrier frequency consumes hundreds of milliwatts of power, an order of magnitude more than the baseband processor.

In a Passive Wi-Fi environment, a hub plugged into an AC outlet continuously transmits the analog carrier frequency. The Passive Wi-Fi device reflects this signal modulated with its own data packets to the receiving device up to 100 feet away at 802.11b speeds (11 Mbps). Because the device does not generate the RF, it uses dramatically less power. To use this technology, wireless routers and access points must also have Passive Wi-Fi built in. See carrier frequency, baseband processor, Wi-Fi, Bluetooth LE and ZigBee.

Personal Use Only

Before/After Your Search Term
passive matrixpassphrase
passive matrix displayPasspoint
passive networkPassport
passive operating system fingerprintingPassport IntRprise
passive optical networkpassthrough SQL
passive polarizationpassword
passive RFID tagpassword chaos
passive starpassword hint
passive testingpassword manager
passive TVpaste

Terms By Topic
Click any of the following categories for a list of fundamental terms.
Computer Words You Gotta KnowSystem design
Job categoriesUnix/Linux
Interesting stuffPersonal computers
InternetIndustrial Automation/Process Control
Communications & networkingAssociations/Standards organizations
HistoryDesktop publishing
ProgrammingHealthcare IT
System design