Table 4: Signal And Energy Detection Threshold For The Primary And Secondary Channels - Grandstream Networks GWN7610 Deployment Manual

a) Basic channel access rules
1. To send 20MHz frame only on a 20MHz primary channel. It only requires performing CCA idle detection
on the 20MHz primary channel, for example, CH60.
2. To send 40MHz frame on the 40MHz primary channel. It requires idle detection on both 20MHz primary
and secondary channel. In above example, CH60 and 64 both are idle.
3. To send 80MHz frames on the 80MHz primary channel. It requires 40MHz primary and 40MHz
secondary both are detected as idle, and pass CCA check, for example, CH52~64 are all idle.
4. To send 160MHz frames on the 160MHz channel. It requires 80MHz primary and 80MHz secondary to
remain idle, and pass CCA check, for example, CH36~64 are idle (GWN7630 will provide support
160MHz channel width).
The CCA sensitivity threshold is listed in Table 6, which provides the signal and energy detection threshold
for the primary and secondary channels:
Channel detection includes signal threshold detection and energy detection. As long as any one of the
detection values indicates busy, CCA idle detection will not pass.

Table 4: Signal and energy detection threshold for the primary and secondary channels

Channel bandwidth
20MHz
40MHz
80MHz
160MHz
b) 802.11ac available bandwidth detection mechanism
802.11ac also provides a bandwidth detection mechanism which allows bandwidth changes on each data
frame transmission. This is achieved by sending CTS copy to target combining channels to detect idle
channels. The number of usable 20MHz combining channels is even, 1/2/4/6, so there is chance to use
60MHz channel.
Signal threshold
(Primary)
-82dBm
-79dBm
-76dBm
-73dBm
Grandstream Wireless Product Deployment Guide
Signal threshold
(Secondary)
-72dBm
-72dBm
-69dBm
N/A
Energy threshold
(Secondary)
-62dBm
-59dBm
-56dBm
N/A
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