Question

Difficulty: MediumTroubleshooting Wireless Connectivity and Signal Issues

A network technician is troubleshooting a newly installed 2.4 GHz Wi-Fi deployment in a open-plan office. Users report frequent packet drops and inconsistent throughput despite showing strong signal indicators on their devices. A wireless spectrum analyzer reveals heavy adjacent-channel interference between three neighboring access points currently configured to operate on channels 1, 3, and 5 with 20 MHz channel widths. Which of the following actions should the technician take to resolve the wireless interference and optimize performance?

  1. Reconfigure the access points to operate on channels 1, 6, and 11 while maintaining a 20 MHz channel width.Answer
  2. B
    Expand the channel width on all access points to 40 MHz to increase overall throughput and override signal noise.
  3. C
    Adjust the channel configuration of the three access points to channels 2, 4, and 6 to eliminate lower-band channel congestion.
  4. D
    Increase the transmit power (dBm) on all access points so the signals can overpower neighboring cell interference.

Answer

Reconfigure the access points to operate on channels 1, 6, and 11 while maintaining a 20 MHz channel width.
In the 2.4 GHz wireless frequency band, 20 MHz channels require a minimum of 25 MHz separation between center frequencies to prevent overlapping. Channels 1, 6, and 11 are the industry-standard non-overlapping channels. Reconfiguring adjacent access points from channels 1, 3, and 5 to channels 1, 6, and 11 eliminates adjacent-channel interference and restores expected wireless throughput.

Step-by-Step Solution

1
Analyze the current wireless channel assignments and physical band characteristics.
The APs operate on 2.4 GHz using 20 MHz channel widths on channels 1, 3, and 5.
Each 20 MHz channel in the 2.4 GHz spectrum extends 10 MHz above and below its center frequency, creating a 22-25 MHz total spectral mask. Channels 1, 3, and 5 overlap heavily with one another.
2
Identify the standard non-overlapping 2.4 GHz channel scheme.
Channels 1, 6, and 11 provide at least 25 MHz of center-frequency separation.
By assigning neighboring access points to channels 1, 6, and 11, adjacent-channel interference is completely eliminated.

Key Concept

2.4 GHz Non-Overlapping Channels
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