A network includes a master and a set of slaves that communicate orthogonal frequency-division multiplexing (OFDM) and time division multiple access (TDMA) symbols on sub-carriers. A master broadcasts to the set of slaves using downlinks and all of the sub-carriers, a broadcast polling packet including data packets for each slave and sub-carrier assignments for the slaves. Each slave, in response to receiving the downlink polling packet, transmits simultaneously a response packet to the master using uplinks and the assigned sub-carriers. The master then transmits to the set of slave using the downlinks and all of the sub-carriers, a group acknowledgement packet, wherein the broadcast polling packet, the response packet, and the group acknowledgement packet comprise one superframe in one communication cycle, and wherein the broadcasting on the downlinks and the transmitting on the uplinks are disjoint in time.
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