The following figure shows a simple logical diagram of Wi-Fi, with the following points worth attention:
The AP and STA both have the TX radio, RX radio, and antenna.
Space loss exists between the AP and STA.
Formula for calculating the received signal strength indicator (RSSI) of the STA (that is, the downlink signal):
Downlink signal power = AP transmit power + AP antenna gain – Space loss + STA antenna gain
Formula for calculating the RSSI of the AP (that is, the uplink signal):
Uplink signal power = STA transmit power + STA antenna gain – Space loss + AP antenna gain
According to the preceding formulas, the AP antenna gain is both added to the signal power. That means that increasing the AP antenna gain can improve the uplink and downlink signal power.
Based on this technical mechanism, Huawei outdoor WLAN APs use built-in high-gain directional antennas, covering the AP8030DN, AP8050DN, and AP8082DN. Such design makes Huawei's outdoor WLAN APs suitable for outdoor narrow road coverage and unidirectional coverage in wall mounting scenarios.
The 2.4 GHz and 5 GHz gains of the preceding APs are 10 dBi, with the antenna's horizontal angle 60° and vertical angle 30Times New Roman. When the –70 dBm signal strength is ensured, the coverage range is 120–150 m. In addition, the built-in antennas spared the cables and installation costs of external antennas.
