A method and system for communicating information over a wireless channel in a communication system including a coordinator and receivers, involves controlling channel access by dividing a contention-free period (CFP) into one or more schedules, wherein each schedule includes one or more periodical channel time blocks (CTBs) for wireless communication, reserving a CTB for reliable broadcast or multicast (ReBoM) communication of a data packet over the channel, transmitting the data packet from the coordinator over the channel during the reserved CTB, and receiving one or more acknowledgments for the data packet from one or more of the receivers. The data packet includes a header comprising ReBoM information indicating a multi-CTB ReBoM communication sequence for the data packet or a single-CTB ReBoM communication sequence for the data packet.