High-Density Wireless Planning
Engineering Capacity in the Age of Mobile Ubiquity
1. The Primary Enemy: Co-Channel Interference (CCI)
In an office with too many Access Points (APs) set to the same channel, they all "hear" each other. Because Wi-Fi is a half-duplex contention-based medium (only one device can talk on a channel at a time), having APs on the same channel reduces the bandwidth for everyone.
Wireless Spectrum & CCI Lab
2.4GHz Frequency Management Board
When APs overlap in frequency, they must wait for each other to stop talking. Red zones indicate airtime contention that drops network capacity.
In high-density areas, use 20MHz channels to maximize the number of non-overlapping "humps" available in your RF map.
2. Channel Width: Bigger is Not Always Better
While 80MHz or 160MHz channels offer exciting "Gigabit" speeds, they are unsuitable for high-density environments.
- 80MHz Channels: Only 5 non-overlapping channels available in 5GHz.
- 20MHz Channels: Up to 25 non-overlapping channels available.
In a stadium, we choose 20MHz channels. This allows us to pack APs closer together without them fighting for the same airwaves.
3. The 6GHz Revolution (Wi-Fi 6E/7)
The introduction of the 6GHz band has provided a massive "spectrum windfall." We now have 1200MHz of clean, uncongested air. For high-density planning, this means we can finally use 40MHz or even 80MHz channels without running out of reuse options.
Conclusion
Success in wireless networking is found in the Efficiency of Airtime. By carefully selecting channel widths, limiting transmit power, and leveraging the new 6GHz spectrum, engineers can build wireless infrastructures that handle the most demanding mobile environments.