An irrigation system includes a network hub and a plurality of remote terminal units configured for wireless communication with the network hub. The remote terminal units are connected to a device for irrigation control or sensing, such as a valve for a sprinkler. The network hub is configured to transmit a wireless broadcast to the remote terminal units, in which the wireless broadcast includes a plurality of individual packets transmitted in succession, each of the plurality of individual packets including a network identifier associated with the network hub, a time remaining in a broadcast period of time, and an assignment map indicative of an assigned state for each of the plurality of remote terminal units.