Network equipment of a wireless communication system comprises a backhaul interface for communicating with a broadcast-based backhaul network and an air interface for communicating with a plurality of mobiles. The network equipment is configured to serve as a proxy on the broadcast-based backhaul network for at least a given one of the mobiles that communicates with the network equipment over the air interface, by determining an IP address for the given mobile and sending a broadcast message over the broadcast-based backhaul network advertising itself as the proxy in association with the IP address. The network equipment may comprise at least a portion of a base station of the wireless communication system. The broadcast-based backhaul network may comprise a local area network that operates in accordance with an Ethernet protocol, and the air interface may comprise an LTE air interface or a WiMAX air interface.