Wi-Fi Operations

This section describes the Wi-Fi operations in different work modes.

Wi-Fi Work Modes

The AIC8800 Wi-Fi subsystem supports two work modes: Station mode and Soft AP mode.

  • Station mode: The device connects to an existing wireless network as a client. This is the default and most common mode.
  • Soft AP mode: The device acts as a wireless access point, allowing other devices to connect to it. This mode is used for local hotspot functionality.

Operations in Station Mode

In Station mode, the device connects to an existing Wi-Fi network.

Table 1. Station Mode Operations
Operation Details
WPA supplicant configuration

  1. Create or edit /etc/wpa_supplicant.conf.

  2. Add the following into the configuration file:
    ctrl_interface=/var/run/wpa_supplicant
update_config=1

  3. Add network entries based on the security type.

    For example:
    • Open system without encryption:
      network={
ssid="tttb"
key_mgmt=NONE
}
    • Open/Shared authentication with WEP encryption:
      network={
ssid="tttb"
key_mgmt=NONE
auth_alg=OPEN SHARED
wep_key0=1234567890
}
    • WPA/WPA2-PSK authentication with TKIP/AES encryption:
      network={
ssid="tttb"
psk="12345678"
}
      Alternatively, generate an encrypted PSK entry using the wpa_passphrase tool:
      wpa_passphrase ssid >> wpa_supplicant.conf
password
Connecting to a network
  1. Run the following command to connect to the network configured in the wpa_supplicant.conf file.
    wpa_supplicant -Dnl80211 -i wlan0 -c wpa_supplicant.conf -d&
  2. After a successful connection, obtain the IP address of wlan0 using the udcpc tool.
    udhcpc -i wlan0
WPA CLI tool wpa_cli is a command-line front-end for interacting with wpa_supplicant . Common operations include:
  • Check WLAN status:
    wpa_cli -p/var/run/wpa_supplicant -iwlan0 status
  • Trigger a scan for nearby WLAN:
    wpa_cli -i wlan0 scan
  • Display scan results:
    wpa_cli -i wlan0 scan_result
  • View all accessible networks and the currently connected network:
    wpa_cli -i wlan0 list_networks
  • Add a new network entry:
    wpa_cli -i wlan0 add_network

  • Set SSID for a network

    wpa_cli -i wlan0 set_network <id> ssid
'"<SSID>"'
  • Set PSK for a network 
    wpa_cli -i wlan0 set_network <id> psk
'"<password>"'

Soft AP Mode Operations

In Soft AP mode, the device acts as a wireless access point.

Table 2. Soft AP Mode Operations
Operation Details
Hotspad configuration

  1. Create or edit /etc/hostapd.conf.

  2. Add the following into the configuration file:
    ctrl_interface=/var/run/wpa_supplicant
update_config=1

  3. Add network entries based on the security type.

    For example:
    • Open system without encryption:
      interface=wlan0
driver=nl80211
ctrl_interface=/var/run/hostapd
ssid=AndroidAP
channel=6
ieee80211n=1
hw_mode=g
ignore_broadcast_ssid=0
    • WPA2-PSK authentication with AES encryption:
      interface=wlan0
driver=nl80211
ctrl_interface=/var/run/hostapd
ssid=AndroidAP
channel=6
ieee80211n=1
hw_mode=g
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_passphrase=12345678
Setting up a Wi-Fi hotspot with hostpad
  1. Run the following command to launch the Wi-Fi hotspot using the hostapd.conf configuration file:.
    hostapd hostapd.conf -B
    After running this command, the hotspot is visible to phones and computers, but client devices fail to establish a connection. This happens because the wireless interface has no assigned IP address and no DHCP server to allocate client IPs. Complete the subsequent steps to resolve this.
  2. Add a dedicated subnet block to the main DHCP configuration file /etc/dhcp/dhcpd.conf. A sample configuration is shown below:
    subnet 192.168.0.0 netmask 255.255.255.0 {
    range 192.168.0.10 192.168.0.20;
    option routers 192.168.0.1;
}
  3. Run the following command to set the static IP for the wlan0 wireless interface.
    ifconfig wlan0 192.168.0.1
  4. Run the following command to start the DHCP server and troubleshoot any runtime errors.
    dhcpd
    You may now connect mobile phones, PCs and other wireless devices to the hotspot. Verify connectivity by pinging the gateway address 192.168.0.1.
  5. To route internet traffic through this Wi-Fi hotspot, enable Linux IP forwarding. This forwards traffic between the SBC’s wired Ethernet port and the wlan0 wireless interface. Run the commands below as an example setup:
    echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -F
iptables -P FORWARD ACCEPT
iptables -t nat -A POSTROUTING -o ethX -j MASQUERADE