Physical layer

802.11 Channels (2.4GHz)

The frequency is divided in channels.

In the UK and most of EU: 13 channels, 5MHz apart, 2.412 – 2.472 GHz.

In the US: only 11 channels.

Each channel is 22 MHz.

Significant overlap.

Best channels are 1, 6 and 11.

Frequency planning

Interference from other WLAN systems or cells.

IEEE 802.11 operates at uncontrolled ISM band.

14 channels of 802.11 are overlapping, only 3 channels are disjointed. For example Ch1, 6, 11.

Throughput decreases with less channel spacing.

A example of frequency allocation in multi-cell network.

5GHz

Uses frequency division in the 5.2 and 5.7 GHz bands.

Greater bandwidth.

Less potential interference (5GHz).

More non-overlapping channels.

Does not provide interoperability.

Interoperability at chipset level.

WiFi 6 radio layer enhancements