Details
The 802.11ac or 802.11ac Wave 2 standard supports the following channel bandwidths: 20 MHz, 40 MHz, 80 MHz, 160 MHz (contiguous), and 80+80 MHz (non-contiguous).
160 MHz (contiguous)
The 160 MHz (contiguous) channel consists of eight adjacent Wi-Fi channels bonded together.
Bandwidth A: Channels 36, 40, 44, 48, 52, 56, 60, and 64
Bandwidth B: Channels 100, 104, 108, 112, 116, 120, 124, and 128
80+80 MHz (non-contiguous)
The 80+80 MHz (non-contiguous) channel consists of two separate 80 MHz bandwidths that bond four contiguous Wi-Fi channels together.
Bandwidth A:
Group 1: Channels 36, 40, 44, and 48
Group 2: Channels 52, 56, 60, and 64
Bandwidth B:
Group 3: Channels 100, 104, 108, and 112
Group 4: Channels 116, 120, 124, and 128
Non-contiguous bandwidths are used for for 802.11ac for several reasons:
Wireless requirements can vary across regions. There may be specific FCC and CE regulations that restrict the use of one or more frequency bands and maximum transmission power across a frequency.
802.11ac operates on the 5 GHz band and this limits the 160 MHz channel spectrum to one or two channels. You can implement the non-contiguous 80+80 MHz mode to avoid interference and channel overlap from nearby routers.
Non-contiguous bandwidths can improve the function of the 160 MHz spectrum. 160 MHz is divided into two 80 MHz bandwidths. Occupying two out of the four contiguous Wi-Fi channels and bonding the channels is more realistic than using a single 160 MHz bandwidth. Channel bonding allows you to select both a low band and high band channel, while omitting Dynamic Frequency Selection (DFS) channels. DFS channels scan for presence of satellite and radar transmissions and switch to a different channel those transmissions are detected. Simultaneously, some routers scan and select a congestion-free Wi-Fi environment for data transmission. These factors can all improve the user experience and provide better network performance.