2.3 Wireless Network Protocols Flashcards
802.11a
54 Mbps
5GHz
Smaller range
802.11b
11 Mbps
2.4 GHz
Slower but better range
802.11g
54 Mbps
2.4GHz
Upgrade to 802.11b
Backwards compatible to 802.11b
802.11n
150 Mbps
2.4 GHz and 5 GHz simultaneously
Backwards compatible with any wireless NIC
MIMO: multiple input/multiple output
802.11ac (WiFi 5)
Nearly 7 Gbps
5 GHz
Multiuser MIMO: multiple clients
802.11ax (WiFi 6)
10-12 Gbps
2.4 GHz and 5 GHz
2.4 GHz vs 5 GHz frequency
2.4 GHz provides more coverage at lower speeds
5 GHz is faster but with less coverage
Channel Regulations
regulations to manage frequency use:
- spectrum use
- power output
- interference requirements
2.4 GHz vs 5 GHz bandwidth
2.4 GHz has three 20 MHz channels
5 GHz has more channels and larger bandwidths (20, 40, 80, 160 MHz)
Bluetooth
- 2.4 GHz
- unlicensed ISM band
- 10 meter range for most consumer devices
- up to 100 meters for some industrial devices
Long-Ranged Fixed Wireless
ex. connecting two buildings using fixed directional antennas
- unlicensed 2.4 GHz or 5 GHz frequencies
- additional licensing may be required
Radio-Frequency Identification (RFID)
ex. access badges, pet ID, tracking devices
- radio energy transmitted to the tag
- radio frequencies power the tag, ID is transmitted back
- bidirectional communication
Near Field Communication (NFC)
- two-way wireless communication
- payment systems (Apple Pay), access cards, mobile apps used to unlock doors
- bootstrap for other wireless ex. helps with bluetooth pairing
Non-overlapping Channels
2.4GHz: Channels 1, 6, 11
MIMO
Multiple Input Multiple Output
- sending and receiving more than one data signal simultaneously over the same radio channel
- uses multiple antennas
Multi-User MIMO
- multiple data signals sent to different receivers
