Week 8 Flashcards
What are WLANS?
Wireless networks (WLANS) are networks that transmit signals through the air via RF (radio frequency) waves.
What is the wireless spectrum?
The wireless spectrum is the frequency range of electromagnetic waves used for data and voice communication
- The spectrum spans from 9kHz to 300GHz
What is RFID?
Radio Frequency Identification uses electromagnetic fields to store data on a small chip in an RFID tag, which includes an antenna and possibly a battery
What is NFC?
Near-field communication (NFC) is a form of RFID that transfers data wirelessly over very short distances. NFC tags can transmit NFC signals and they collect power from a smartphone or other device by magnetic induction
What is Z-Wave?
Z-Wave is a smart home protocol that:
- Signals to manage wireless connections
- Control to transmits data and commands between devices
A Z-Wave network controller receives commands from and relays the commands to connected smart devices
What is ZigBee
ZigBee is a low-powered, battery-conserving wireless technology designed to handle small amounts of data and is used in IoT devices
What is Bluetooth?
Bluetooth technology unites separate entities under a single communication standard. Bluetooth devices need to be close to form a connection.
What is ANT+?
ANT+ is an ad-hoc wireless protocol that gathers and tracks information from sensors typically embedded in heart rate monitors, GPS devices, and other activity monitoring devices
What is IR (infrared) technology?
IR (infrared) technology is used primarily to collect data through various sensors such as:
- The presence or level of a liquid
- Proximity to the device
- Commands from a control device
What is an antennas radiation pattern?
An antenna’s radiation pattern describes the relative strength over a three-dimensional area of all electromagnetic energy that an antenna sends or receives
What are the two types of antenna?
- Directional (unidirectional) antenna – Issues wireless signals along a single direction
- Omnidirectional antenna – Issues and receives wireless signals with equal strength, clarity in all directions
What are the different types of signal propagation?
- Attenuation – the farther the signal moves away from the transmission source, the more it weakens
- Fading - as a signal runs into obstacles, its energy will gradually fade
- Interference - when electromagnetic waves interfere with wireless communications
- Refraction - when a waves direction, speed and wavelength are altered because it travelled through an object
- Reflection - when a wave bounces off an object back to it’s source
- Scattering - when a wave encounters an object with small dimensions it diffuses or scatters in multiple directions
- Diffraction - when a wave is split into secondary waves when it encounters an obstruction
What layers of the OSI model do WLANs work at?
Layers 1 and 2
What is frame aggregation?
Frame aggregation combines multiple frames into one larger frame.
What is channel bonding?
Channel bonding is where two adjacent channels with the same frequency can be bonded to make one channel that has more than double the bandwidth
