Examkin

Question

Difficulty: MediumWireless Network Deployment and Standards

A network administrator is configuring three neighboring access points installed along a corridor in an enterprise building. The access points operate on standard 20 MHz channel widths within the 2.4 GHz spectrum. Which of the following channel assignment combinations will ensure contiguous wireless coverage while completely preventing adjacent-channel interference?

  1. Channels 1, 6, and 11Answer
  2. B
    Channels 1, 5, and 9
  3. C
    Channels 2, 7, and 12
  4. D
    Channels 3, 6, and 9

Answer

Channels 1, 6, and 11 represent the three primary non-overlapping 20 MHz channels available in the 2.4 GHz spectrum.
In the 2.4 GHz band, channels are spaced 5 MHz apart. Standard 20 MHz transmissions require a minimum separation of 5 channel numbers (25 MHz between center frequencies) to prevent frequency skirts from overlapping. Channels 1, 6, and 11 represent the standard set of non-overlapping channels in North America and international deployments.

Step-by-Step Solution

1
Analyze the channel spacing and bandwidth structure of the 2.4 GHz ISM band.
Each channel number represents a 5 MHz shift in center frequency, while a standard channel mask spans 20 to 22 MHz.
Because center frequencies are separated by only 5 MHz, adjacent channel numbers overlap heavily.
2
Calculate the minimum separation needed between channel center frequencies to avoid overlap.
A minimum separation of 25 MHz (5 channel numbers) is necessary to keep signal skirts isolated.
Sufficient frequency separation prevents adjacent-channel interference, which impairs frame preamble detection and causes packet corruption.
3
Identify the standard non-overlapping channel plan for three adjacent coverage cells.
Assigning channels 1 (2412 MHz), 6 (2437 MHz), and 11 (2462 MHz) provides 25 MHz separation between all adjacent access points.
This allocation maintains maximum cell density without generating inter-cell interference.

Key Concept

2.4 GHz Non-Overlapping Channel Planning
Rate this question

Topics

Wireless Network Deployment and Standards

More questions from this topic