A wireless subnet contains node/interfaces. Once a node/interface is a member of a subnet, it is unavailable to other subnets. The Physical Layer of the wireless subnet includes radio type, transmitter powers, receiver sensitivities, and noise properties.
To define the wireless subnet, right-click 
Connections and select Wireless Subnet... from the right-click menu. Make the following selections on the Add Wireless Subnet window and click OK.
Name. Name of the subnet. The default name is Subnet<no.>.
IPv4Address. 32-bit address that identifies the wireless subnet in the IPv4 network. An example IPv4Address is 190.0.0.0
Subnet Mask. IPv4 subnet mask assigned to the interface. All interfaces on a subnet share a 32-bit subnet mask. An example subnet mask is 255.255.255.0.
Available Interfaces. List of interfaces that are not members of another subnet. Use the right arrow to add selected interfaces to this wireless subnet.
Selected Interfaces. List of interfaces that are members of this subnet. Use the left arrow to remove selected interfaces from this wireless subnet.
Assign IP address to match base IP. Creates an IP address for this wireless subnet `that matches the IPv4Address.