A transmitter generates MUX-PDUs for video, audio, data, and/or control streams based on a fixed PHY packet size such that all or a substantial percentage of the MUX-PDUs conform to the PHY packet size. The MUX-PDUs have variable sizes and are mapped to PHY packets such that (1) each MUX-PDU that is smaller than the PHY packet size is sent in one PHY packet and (2) each MUX-PDU that is larger than the PHY packet size is sent in a minimum number of PHY packets. Each MUX-PDU is padded with one or more null MUX-PDUs and/or one or more padding bytes, if needed, to obtain the PHY packet size. Each PHY packet is sent in one transmission time interval (TTI) to a receiver. The receiver performs the complementary processing on the received PHY packets to recover the MUX-PDUs. The receiver forwards each valid MUX-PDU and discards any padding.