Soru

Zorluk: OrtaWireless Network Deployment and Standards

A network administrator notices severe throughput degradation and high frame retransmission rates across a newly deployed 2.4 GHz2.4\text{ GHz} wireless network serving four adjacent open-office zones. Reviewing the wireless controller configuration reveals that neighboring access points are currently statically assigned to channels 1, 4, 7, and 10. Which configuration change must the administrator implement to eliminate adjacent channel interference (ACI) between the neighboring access points?

  1. Reassign the access points to operate using only channels 1, 6, and 11, reusing channel 1 on the access point farthest from the initial channel 1 deployment.Cevap
  2. B
    Reassign the access points to channels 2, 5, 8, and 11 to achieve an even 3-channel spacing across the available frequency band.
  3. C
    Enable 40 MHz channel bonding across channels 1 and 7 to increase throughput and bypass channel spacing restrictions.
  4. D
    Increase the transmit power on access points operating on channels 4 and 7 to override background noise from channels 1 and 10.

Cevap

Reassign the access points to operate using only channels 1, 6, and 11, reusing channel 1 on the access point farthest from the initial channel 1 deployment.
In the 2.4 GHz Wi-Fi band, each channel occupies 20 MHz of channel bandwidth while center frequencies are spaced only 5 MHz apart. Therefore, only channels 1, 6, and 11 provide complete frequency separation without spectral overlap. In a four-AP deployment, assigning adjacent APs to 1, 6, and 11 and placing the second channel 1 AP at the maximum physical distance ensures clean cell boundary separation and eliminates adjacent channel interference.

Adım Adım Çözüm

1
Identify the cause of performance degradation
Channels 1, 4, 7, and 10 each have a 20 MHz channel width (spaced only 5 MHz apart per channel step), causing their signal sidebands to overlap and create adjacent channel interference (ACI).
Adjacent channel interference occurs when overlapping Wi-Fi frequencies cause uncoordinated energy spills, leading to frame corruption and retransmissions.
2
Determine the non-overlapping channel scheme for the 2.4 GHz band
The standard non-overlapping 20 MHz channels in the 2.4 GHz ISM band (802.11b/g/n/ax) are channels 1, 6, and 11.
Each standard channel is 20 MHz wide with 5 MHz separation between center frequencies, requiring a minimum of 25 MHz (5 channels) separation between non-overlapping center frequencies.
3
Apply cellular channel reuse design
Assign channels 1, 6, and 11 to adjacent access points and repeat channel 1 on the fourth access point, ensuring maximum physical distance between the two channel 1 cells.
Proper channel reuse minimizes co-channel interference (CCI) while completely preventing adjacent channel interference (ACI).

Anahtar Kavram

2.4 GHz Non-Overlapping Channel Planning
Bu soruyu puanla