EXAMINING THE 802.11 STANDARD

Question 1

What are the 802.11 standards?

Answer 1

The IEEE’s working group for wireless local area networks (WLAN)

The 802.11 standards define the protocols for implementing wireless local area network (WLAN) communication.

Question 2

What are the 802.11 standards to be aware of?

Answer 2

802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ax, 802.11be (in development)

These standards represent various generations of Wi-Fi technology.

Question 3

What are the characteristics of 802.11a?

Answer 3

• Speed - Up to 54 Mbps
• Frequency - 5 GHz
• Range - Shorter range due to higher frequency
• Interference - Less interference
• Wi-Fi Alliance Name - Wi-Fi 2 (unofficially)

802.11a operates in the 5 GHz band which allows for higher speeds but shorter range.

Question 4

What are the characteristics of 802.11b?

Answer 4

• Speed - Up to 11 Mbps
• Frequency - 2.4 GHz
• Range - Good range due to lower frequency
• Interference - More interference (many devices use 2.4 GHz)
• Wi-Fi Alliance Name - Wi-Fi 1 (unofficially)

802.11b’s lower frequency provides better range but is more susceptible to interference from other devices.

Question 5

What are the characteristics of 802.11g?

Answer 5

• Speed - Up to 54 Mbps
• Frequency - 2.4 GHz
• Range - Good range, similar to 802.11b
• Interference - More interference (2.4 GHz is commonly used)
• Wi-Fi Alliance Name - Wi-Fi 3 (unofficially)

802.11g combines the speed of 802.11a with the range of 802.11b.

Question 6

What are the characteristics of 802.11n?

Answer 6

• Speed - Up to 600 Mbps
• Frequency - 2.4 GHz and 5 GHz
• Range - Better than 802.11a/g, option for 2.4 GHz improves range
• Interference - The 2.4 GHz band has more interference, less on the 5 GHz
• Wi-Fi Alliance Name - Wi-Fi 4
• MIMO - Supported (up to 4x4)

802.11n introduces MIMO technology which allows multiple antennas to improve performance.

Question 7

What is the maximum speed of 802.11ac (Wi-Fi 5)?

Answer 7

Up to 6.9 Gbps

Question 8

What frequency does 802.11ac (Wi-Fi 5) operate on?

Answer 8

5 GHz

Question 9

What is the range characteristic of 802.11ac (Wi-Fi 5)?

Answer 9

Shorter than 2.4 GHz networks, better with beamforming

Question 10

How does interference compare in 802.11ac (Wi-Fi 5)?

Answer 10

Less crowded, minimal interference

Question 11

What is the Wi-Fi Alliance name for 802.11ac?

Answer 11

Wi-Fi 5

Question 12

Is MIMO supported in 802.11ac (Wi-Fi 5)?

Answer 12

Supported (up to 8x8)

Question 13

Is MU-MIMO supported in 802.11ac (Wi-Fi 5)?

Answer 13

Supported

Question 14

What is the maximum speed of 802.11ax (Wi-Fi 6)?

Answer 14

Up to 9.6 Gbps

Question 15

What frequencies does 802.11ax (Wi-Fi 6) operate on?

Answer 15

2.4 GHz and 5 GHz

Question 16

What is the range characteristic of 802.11ax (Wi-Fi 6)?

Answer 16

Improved over Wi-Fi 5, especially in the 2.4 GHz band

Question 17

How does interference compare in 802.11ax (Wi-Fi 6)?

Answer 17

Technologies like OFDMA reduce interference

Question 18

What is the Wi-Fi Alliance name for 802.11ax?

Answer 18

Wi-Fi 6

Question 19

Is MIMO supported in 802.11ax (Wi-Fi 6)?

Answer 19

Supported (up to 8x8)

Question 20

Is MU-MIMO supported in 802.11ax (Wi-Fi 6)?

Answer 20

Supported

Question 21

What is the expected maximum speed of 802.11be (Wi-Fi 7)?

Answer 21

Expected to exceed 30 Gbps

Question 22

What frequencies does 802.11be (Wi-Fi 7) operate on?

Answer 22

2.4 GHz, 5 GHz, and 6 GHz

Question 23

What is the anticipated range characteristic of 802.11be (Wi-Fi 7)?

Answer 23

Anticipated to offer enhanced range with new technologies

Question 24

How is interference expected to be managed in 802.11be (Wi-Fi 7)?

Answer 24

Expected to be managed with advanced techniques

Question 25

What is the Wi-Fi Alliance name for 802.11be?

Answer 25

Wi-Fi 7 (anticipated)

Question 26

Is MIMO supported in 802.11be (Wi-Fi 7)?

Answer 26

Supported (expected to support higher than 8x8)

Question 27

Is MU-MIMO supported in 802.11be (Wi-Fi 7)?

Answer 27

Supported

Question 28

What is MIMO (Multiple Input Multiple Output)?

Answer 28

A technology using multiple antennas at both the transmitter and receiver.

Question 29

How does MIMO enhance communication performance?

Answer 29

Enhances communication performance, data rates, and network capacity by using multiple signal paths.

Question 30

What is MU-MIMO (Multi-User MIMO)?

Answer 30

An advancement of MIMO technology.

Question 31

How does MU-MIMO improve network efficiency?

Answer 31

Allows multiple users to simultaneously access the same network.

Question 32

What is a key feature of MU-MIMO regarding antennas?

Answer 32

Each user has their own dedicated set of multiple antennas, improving network efficiency and throughput.

Question 33

Why are channels important in WLANs?

Answer 33

Channels are important because each frequency used has specific channels and channel numbers.

Question 34

How many channels does 2.4 GHz use in North America?

Answer 34

2.4 GHz uses 11 channels in North America.

Question 35

How many non-overlapping channels does 2.4 GHz have?

Answer 35

2.4 GHz has three non-overlapping channels: 1, 3, and 11.

Question 36

Are all channels in 5 GHz overlapping?

Answer 36

No, all channels in 5 GHz are non-overlapping.

Question 37

What are the bands labeled in 5 GHz?

Answer 37

The bands in 5 GHz are labeled UNIl.

Question 38

What feature do some channels in 5 GHz support?

Answer 38

Some channels support dynamic frequency selection to allow wireless communication in the same channels as radar operates.