A communication unit (110) that wants to transmit a data packet to another communication unit (105) must acquire access to a common communication channel (not shown) before transmitting a data packet (440). For data packets of realtime applications, quality of service (QOS) parameters for the data packet are used to define transmission parameters to communicate the data packet (440). These parameters include T_access (420) and T_delay (430). In addition, compliance with predetermined requirements of size relationship between request-to-send (RTS) and clear-to-send (CTS) packets are imposed.