Channel Bandwidth
The channel bandwidth defines the width of the frequency band used by a wireless signal, typically measured in megahertz (MHz). It directly determines the spectral occupation and maximum data-carrying capacity of the transmission.
Scope and Application
Channel bandwidth is a key configuration parameter in Wi-Fi communication. Typical bandwidths include 20 MHz, 40 MHz, 80 MHz, and 160 MHz (as used in Wi-Fi 5 and Wi-Fi 6), with 320 MHz introduced in Wi-Fi 7 (802.11be). Wider bandwidths support higher data rates but increase the risk of interference and spectral overlap.
Bandwidth usage is subject to national and international regulations:
ETSI: EN 300 328 (2.4 GHz), EN 301 893 (5 GHz), and EN 303 687 (Wi-Fi 6E/7 in 6 GHz)
ISED: RSS-247
Key Technical Requirements
Occupied Bandwidth (OBW) is defined as the bandwidth containing 99% of the transmitted signal power and must be verified during testing.
The emission mask specifies how much power is allowed to leak outside the intended channel and is tightly linked to the configured bandwidth.
In the 5 GHz band, channel bonding (e.g., using 40 MHz or 80 MHz) must comply with DFS requirements and respect the sub-band designations of the UNII spectrum.
Certification and Compliance
For regulatory compliance, the channel bandwidth must:
Match the device's operational mode (e.g., HT20, HT40, VHT80, EHT320)
Be confirmed through spectral analysis (e.g., OBW or -6 dB bandwidth)
Conform to the applicable emission mask and test conditions
Configuration and Testing Relevance
Device Configuration: Channel bandwidth must be selectable and aligned with regional regulations.
Testing: Measurement of OBW, spurious emissions, and frequency stability depends on bandwidth settings.
Documentation: Regulatory test reports must include the configured bandwidth and measurement results to verify compliance.