How are the frequency bands and channels of 2.4G and 5G divided?

2.4G frequency band
As shown in Figure 1, the 2.4G frequency band is divided into 14 overlapping, staggered 20MHz channels, with channel codes from 1 to 14, and there is a certain overlap between adjacent channels.

Figure 1 2.4G frequency band channel distribution

Take channel 1 as an example. It can be seen from the figure that at least channel 5 is required to have no overlapping area with channel 1. In general scenarios, it is usually recommended to use a channel combination of 1, 6, and 11 with at least 4 channels each to deploy cellular wireless network coverage, as shown in Figure 2. Similarly, you can also use a combination of 2, 7, 12 or 3, 8, 13. In high-density scenarios, it is usually recommended to use a combination of 1, 9, 5, and 13 channels, as shown in Figure 3.

5G frequency band
As shown in Figure 4, the 5G frequency band has richer resources and has more 20MHz channels than the 2.4G frequency band. And adjacent channels do not overlap, such as channels 36 and 40.

Figure 4 5G frequency band channel distribution

The radar system in some areas works in the 5G frequency band, which will interfere with the AP radio frequency signal working in the 5G frequency band. Radar signals may interfere with channels 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144 (of which 120, 124, and 128 are weather radar channels). If the channel on which the radio frequency works is manually specified, pay attention to avoid the radar channel when planning the channel. If the channel on which the radio frequency works is dynamically adjusted by the system, the system will automatically switch the working channel when it detects interference in the working channel.

The 320MHz bandwidth of the 5G band is fixed at 240MHz due to limited continuous channels.

Channel bundling
In order to increase the wireless network rate of wireless terminals, the channel working bandwidth of the radio frequency can be increased. If two 20MHz channels are bundled together into a 40MHz channel, and data is sent to a wireless terminal at the same time, theoretically the data channel is doubled and the rate is doubled. If two 40MHz channels are bundled, the rate will double again, and so on. According to different channel bundling methods, the channel working bandwidth can be divided into 40MHz+, 40MHz-, 80MHz, 80+80MHz, and 160MHz. As shown in the figure below, the channels that can be bundled in pairs are fixed.

40MHz+ and 40MHz-: Two adjacent non-interfering channels are bundled into a 40MHz channel, one of which is the main channel and the other is the slave channel. If the center frequency of the main channel is higher than the center frequency of the slave channel, it is 40MHz-, otherwise it is 40MHz+. For example, channels 36 and 40 are bundled into 40MHz. If the main channel is channel 40, it is 40MHz-, and if the main channel is 36, it is 40MHz+. It is generally not recommended to use 40MHz on the 2.4GHz band. If 40MHz is configured, there can only be one non-overlapping 40MHz channel in the band. For example, channel 1 can only form a 40MHz channel with channel 5 (channels 1 and 2, 3, and 4 have overlapping areas), and the remaining channel combinations must avoid channels 1 to 8 (channels 5 and 6, 7, and 8 have overlapping areas). Therefore, the remaining channels cannot form another 40MHz channel.

80MHz: Two consecutive 40MHz channels are bundled together to form 80MHz. Any of the four 20MHz channels in 80MHz can be selected as the main channel. For example, 36, 40, 44, and 48 are bundled into 80MHz.
80+80MHz: Two non-continuous 80MHz channels are bundled together to form 80+80MHz. For example, 36, 40, 44, 48, 100, 104, 108, and 112 are bundled into 80+80MHz.
160MHz: Two consecutive 80MHz channels are bundled together to form 160MHz. Any of the eight 20MHz channels in 160MHz can be selected as the main channel. For example, 36, 40, 44, 48, 52, 56, 60, and 64 are bundled into 160MHz.
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