A network communication system is provided for communication between network nodes, including individual nodes and a communication controller. In the network, signals are transmitted from the communication controller to identify a slot of a frame in which individual nodes may transmit a request to transmit data. When a first individual node has data to transmit, the first node transmits a request signal to the controller in its identified slot, the request including randomly generated information (RGI) for identification of the node. In response to the request signal, the controller transmits a grant signal along with the RGI back to the first node to allow the first node to identify the grant.