Wireless Networks Lesson 001: Wireless Frequencies

Wireless Networking

Operates across various frequency bands and uses specific transmission methods to optimize its performance.

What frequency bands do modern networks utilize?

2.4 GHz, 5 GHz, and 6 GHz.

Direct Sequence Spread Spectrum (DSSS)

A legacy wireless communication method that transmits across the entire frequency range.

How does a DSSS method work?

By using signal patterns known as chips.

What is the benefit of using a DSSS in networking?

It is effective in reducing interference across wide areas.

What is the caveat of using a DSSS in networking?

It is vulnerable to EMI and does not use a full channel system.

Why does DSSS not use a full channel system?

Channels need to be left untouched because of the channels interfering with one another.

What is the only wireless standard that uses DSSS?

802.11 and 802.11b.

What is Orthogonal Frequency Division Multiplexing?

A modern wireless communication method.

What does OFDM stand for?

Orthogonal Frequency Division Multiplexing.

What does an OFDM do?

Divides data transmission into smaller subchannels that can carry a portion of data.

What is the benefit of OFDM?

This technique mitigates interference and enables higher rates of data.

Wireless Channel

"Virtual pipes" for data transmission.

What defines a wireless channel?

The width and placement within a given frequency band.

What is the goal in wireless channel selection?

To minimize interference and maximize wireless network performance.

Why are three different wireless frequency bands used?

To have the ability to configure networks to ensure that needs for speed, range and interference resistance are met.

Why is it important to understand the three different wireless network bands?

To optimize network performance.

2.4 GHz Frequency Band

Operates within the frequency range of 2.4 and 2.5 GHz.

What is the 2.4 GHz frequency band characterized by?

Longer range due to lower frequency.

What is the caveat to using a 2.4 GHz frequency band?

Many other devices use this frequency range, making it susceptible to interference.

What other devices use the 2.4 GHz frequency band?

Microwaves, Bluetooth, and cordless phones.

How many channels are available on the 2.4 GHz frequency band?

14 channels.

How wide is each of the 14 channels available on a 2.4 GHz frequency band?

22 MHz wide.

What is extremely important to keep in mind when choosing a channel to use in the 2.4 GHz frequency band?

There is a lot of overlap that occurs between channels.

Which channels of the 2.4 GHz frequency band are considered best practice use cases and why?

Channels 1, 6, and 11 in order to prevent overlapping interference.

5 GHz Frequency Band

Covers a frequency of 5.725 to 5.875 GHz, though specific ranges may vary by region.

Channel Bonding

Enables the creation of wider channels such as 40 MHz, 80 MHz, or 160 MHz.

How does channel bonding work?

By merging adjacent channels to increase throughput dramatically.

What is the caveat to channel bonding?

It uses more resources by using more of the 5.4 GHz frequency and leaving less non-overlapping channels available.

What potential issue comes with the utilization of channel bonding?

The increase for potential interference in densely populated wireless environments.

6 GHz Frequency Band

Spans frequencies from 5.925 to 7.125 GHz and introduces up to 59 non-overlapping 20 MHz channels and wider bonded channel support.

What is the range of the 6 GHz frequency band?

The shortest of the three frequency bands.

What is the 6 GHz frequency band exclusively used for?

For Wi-Fi 6e and newer devices, ensuring minimal interference from older devices and hardware.

What are the benefits of using 6 GHz frequency band?

High speed, high capacity applications, especially in network congested and high interference environment.