2.4 - Wireless Network Technologies

Question 1

802.11 Technololgies

Answer 1

• Frequency
• 2.4 GHz or 5 GHz (and sometimes both)
• Channels
• Groups of frequencies, numbered by the IEEE
• Non-overlapping channels would be necessary
• Bandwidth
• Amount of frequency in use
• 20 MHz, 40 MHz, 80 MHz, 160 MHz

Question 2

802.11 Channel Bandwidths

Answer 2

• 802.11a - 20 MHz
• 802.11b - 22 MHz
• 802.11g - 20 MHz
• 802.11n
• 20 MHz or 40 MHz
(two contiguous 20 MHz bonded channels)
• In 2.4 GHz, a 40 MHz channel uses
much of the available bandwidth
• 802.11ac
• 40 MHz for 802.11n stations
• 80 MHz required for 802.11ac stations
• 160 MHz optional (contiguous channels or noncontiguous
bonded channels)

Question 3

Bluetooth

Answer 3

• High speed communication over short distances
• PAN (Personal Area Network)
• Connects our mobile devices
• Smartphones
• Tethering and file transfers
• Headsets and headphones
• Health monitors
• Automobile and phone integration
• Smartwatches
• External speakers

Question 4

Near Field Communications (NFC)

Answer 4

• Two-way wireless communication
• Builds on RFID, which is mostly one-way
• Payment systems
• Major credit cards
• Online wallets
• Bootstrap for other wireless
• NFC helps with Bluetooth pairing
• Access token, identity “card”
• Short range with encryption support

Question 5

RFID (Radio-Frequency Identification

Answer 5

• It’s everywhere
• Access badges
• Inventory/Assembly line tracking
• Pet/Animal identification
• Anything that needs to be tracked
• Radar technology
• Radio energy transmitted to the tag
• RF powers the tag, ID is transmitted back
• Bidirectional communication
• Some tag formats can be active/powered

Question 6

Zigbee

Answer 6

• Internet of Things networking
• Open standard - IEEE 802.15.4 PAN
• Alternative to WiFi and Bluetooth
• Longer distances than Bluetooth
• Less power consumption than WiFi
• Mesh network of all Zigbee devices in your home
• Light switch communicates to light bulbs
• Tell Amazon Echo to lock the door
• Uses the ISM band
• Industrial, Scientific, and Medical
• 900 MHz and 2.4 GHz frequencies in the US

Question 7

Z-Wave

Answer 7

• Proprietary home automation networking
• Internet of Things (IoT)
• Control lights, locks, garage doors, etc.
• Wireless mesh networking
• Nodes can hop through
other nodes on
the way to the destination
• Uses the ISM band
• Industrial, Scientific,
and Medical
• 900 MHz frequencies in the US
• No conflicts with 802.11

Question 8

Cellular Networks

Answer 8

• Mobile devices
• “Cell” phones
• Separate land into “cells”
• Antenna coverages a cell with certain frequencies
• 2G networks
• GSM - Global System for Mobile Communications
• CDMA - Code Division Multiple Access
• Poor data support
• Originally used circuit-switching
• Minor upgrades for some packet-switching

Question 9

3G Technology

Answer 9

• 3rd Generation
• Introduced in 1998
• Upgraded data connectivity over 2G
• Incremental 3G updates improved speeds
• Usually several megabits per second
• Bandwidth improvement allowed new functionality
• GPS
• Mobile television
• Video on demand
• Video conferencing

Question 10

4G and LTE

Answer 10

• Long Term Evolution (LTE)
• A “4G” technology
• Converged standard (GSM and CDMA providers)
• Based on GSM and
• EDGE (Enhanced Data Rates for GSM Evolution)
• Standard supports download rates of 150 Mbit/s
• LTE Advanced (LTE-A)
• Standard supports download rates of 300 Mbit/s

Question 11

Moving to 5G

Answer 11

• Update to 4G - Rollout in late 2018 and 2019
• Worldwide launches in 2020
• Significant performance improvements
• At higher frequencies
• May not be as significant at lower frequencies
• Technology updates
• Additional frequencies
• Improved data transmission methods