2.3 - Wireless Standards

Question 1

Tell me about 802.11a.

Answer 1

One of the original 802.11 wireless standards. Operates in the 5 GHz range, though can operate on other frequencies with special licensing. 54 megabits / second. These are not common in use today,

Question 2

Why does a 5 GHz frequency have a smaller range than a 2.4 ghz frequency?

Answer 2

The higher the frequency, the smaller the wavelength. Smaller wavelengths have difficulties penetrating objects (don’t you dare).

Question 3

Tell me about 802.11b.

Answer 3

Another one of the original 802.11 wireless standards. Operates in the 2.4 GHz range. 11 megabits per second.

Question 4

What is the downside to the 2.4 GHz frequency?

Answer 4

Other devices (baby monitors, Bluetooth, cordless phone) also use this frequency.

Question 5

Tell me about 802.11g.

Answer 5

This was an upgrade to 802.11b. It offered 54 megabits / seconds speeds (like 802.11), but operated on the 2.4 GHz range which meant that it has the same frequency conflict issues as 802.11b.

Question 6

Tell me about 802.11n.

Answer 6

AKA Wi-Fi 4. Operates at 5 GHz and/or 2.4 GHz. Uses a 40 MHz channel width which allows for up to 600 megabits / second. Introduced MIMO (multiple-input multiple-output), which allows for faster data transfers between the end station and the access point.

Question 7

Tell me about 802.11ac.

Answer 7

AKA Wi-Fi 5. Operates in the 5 GHz band, with more frequencies up to a 160 MHz channel bandwidth. Added MU-MIMO downlink streams, twice as many streams as 802.11n. Nearly 7 gigabits per second.

Question 8

What are the 802.11 standards, in order?

Answer 8

802.11a/b, 802.11g, 802.11n, 802.11ac, 802.11ax.

Question 9

Tell me about 802.11ax.

Answer 9

AKA Wi-Fi 6. Operates at 5 GHz and/or 2.4 GHz, with 20, 40, 80, and 160 MHz channel widths. Only 1.2 GHz / second (versus 1 GHz in Wi-Fi 5), BUT added OFDMA.

Question 10

What is OFDMA, and when is it helpful?

Answer 10

Orthogonal frequency-division multiple access. Most helpful when there are a number of people.

Question 11

What sorts of things are regulated by the government when it comes to long-range fixed wireless?

Answer 11

Frequency use, signal strength, and outdoor antenna instillation.

Question 12

What is RFID, and when is it used?

Answer 12

Radio-frequency identification. Used in access badges, inventory/assembly line tracking, pet/animal identification.