802.11a coverage at maximum rate: At the highest 802.11a data rate (54 Mbps), what is the typical maximum indoor distance achievable?

Introduction / Context:
5 GHz links (802.11a) provide higher data rates but generally shorter range than 2.4 GHz due to higher path loss and reduced wall penetration. At the top PHY rate, the SNR requirement is highest, limiting reach.

Given Data / Assumptions:

• Standard: 802.11a, 5 GHz, 20-MHz channel, 54 Mbps PHY.
• Indoor environment with typical attenuation.

Concept / Approach:
Maximum rate requires robust SNR. Indoor design references frequently quote ~65–75 ft (20–23 m) for 54 Mbps stability in normal buildings; rates drop as you move farther from the AP.

Step-by-Step Solution:

Verification / Alternative check:
AP data sheets and site survey guides match this order of magnitude for high-rate service areas.

Why Other Options Are Wrong:

• 90–100/150/200+ ft: More consistent with lower rates (e.g., 24, 12, or 6 Mbps).
• 30 ft: Too conservative for typical interior offices.

Common Pitfalls:
Assuming all 5 GHz coverage is short; rate adaptation will extend distance by lowering the PHY rate.

Final Answer:
About 65–75 feet