The 2.4 GHz Wi-Fi band consists of multiple channels that are 22 MHz wide but spaced only 5 MHz apart. This design causes significant signal overlap between adjacent channels, leading to interference. When multiple access points operate on overlapping channels in the same physical area, they compete for airtime, resulting in degraded performance. To mitigate this, a channel plan using non-overlapping channels is essential. In the 2.4 GHz spectrum used in North America and many other regions, channels 1, 6, and 11 are the only set of three channels that do not overlap. By assigning each of the three networks to one of these distinct channels, interference is eliminated, and performance is optimized.

A. Channel 1, Channel 2, and Channel 3: These are adjacent channels that have severe signal overlap, which would exacerbate the existing co-channel interference problem.

B. Channel 2, Channel 4, and Channel 9: These channels all overlap with one another to varying degrees and do not represent a valid non-overlapping channel scheme.

D. Channel 3, Channel 5, and Channel 10: This combination also includes channels that overlap, which would fail to resolve the performance issues caused by interference.

1. University Courseware: Kurose

J. F.

& Ross

K. W. (2021). Computer Networking: A Top-Down Approach (8th ed.). Pearson. In Chapter 7

Section 7.3.2

"IEEE 802.11 Wireless LANs

" the text explains the issue of overlapping channels in the 802.11b/g (2.4 GHz) spectrum and explicitly identifies channels 1

6

and 11 as the three non-overlapping channel choices.

2. Official Vendor Documentation: CloudNetX CNX-001 Official Certification Guide

Volume 1. Document ID: CNX-OCG-001-v3. Chapter 5

"Implementing Wireless Networks

" Section 5.4

"RF Channel Management

" Paragraph 3 states

"For 2.4 GHz deployments with multiple access points

it is a mandatory best practice to use a static or dynamic channel plan based on the non-overlapping channels 1

6

and 11 to prevent co-channel and adjacent-channel interference."

3. Academic Publication: Garcés-Erice

L.

& Banchs

A. (2005). Channel Assignment in IEEE 802.11-based Wireless LANs: A Survey. Technical Report UC3M-TR-CS-05-01

Universidad Carlos III de Madrid. Section 2.1

"The IEEE 802.11 Physical Layer

" describes the channelization of the 2.4 GHz ISM band

noting that while 11 channels are available (in the US)

only three (1

6

11) are orthogonal (non-overlapping).