Channel Planning — Non-overlapping channels available with 802.11g (2.4GHz) In the 2.4GHz band as used by IEEE 802.11g, how many non-overlapping 20MHz channels are available in most regulatory domains (for example, channels 1, 6, and 11)?

Introduction / Context:
Effective 2.4GHz WLAN design hinges on proper channel reuse. Because adjacent channels overlap significantly in 2.4GHz, only a small subset of channels can be reused without co-channel or adjacent-channel interference. Designers typically rely on the classic trio for minimal overlap.

Given Data / Assumptions:

• Channel width is 20MHz.
• Regulatory domain similar to North America with channels 1–11.
• Goal is to count non-overlapping channels in typical planning.

Concept / Approach:
With 20MHz channels in 2.4GHz and center-frequency spacing of 5MHz, adjacent channels overlap. The conventional non-overlapping set in many domains is channels 1, 6, and 11. Some regions allow channel 13, enabling different triplets, but the standard practice still yields three non-overlapping channels. This limitation drives many enterprises toward 5GHz for higher capacity.

Step-by-Step Solution:
Confirm band and width: 2.4GHz, 20MHz channels.Recall typical non-overlapping set: 1/6/11.Count the set size: 3.Select “3.”

Verification / Alternative check:
Site surveys and vendor guides consistently recommend a 3-channel reuse plan in 2.4GHz for minimal interference in most regions.

Why Other Options Are Wrong:

• 12, 23, 40: Numbers more typical of 5GHz channels, not 2.4GHz non-overlapping counts.
• 4: Occasionally cited in special cases (different channel widths/regional rules), but standard 20MHz planning widely uses 3.

Common Pitfalls:
Assuming every listed channel is usable concurrently; overlap constraints limit practical non-overlapping choices to three in most domains.

Final Answer:
3