Optimisation for data transmission

A method of optimizing data for transmission, the method comprising:

• determining a plurality of data packets to be transmitted at a first transmission rate;
• determining required modulation and encoding schemes (MODCODs) for bits of the plurality of data packets;
• assigning the bits of the plurality of data packets to a respective baseband transmission frame (BBFRAME) of a sequence of BBFRAMEs, in accordance with the required MODCODs for respective bits, such that each of the BBFRAMEs is associated with a highest common MODCOD robustness of the required MODCODs for each of the bits in the BBFRAME, wherein a robustness of a MODCOD associated with each of the BBFRAMEs increases or decreases in accordance with a chronological position in the sequence of BBFRAMEs, wherein the assigning of the bits of the plurality of data packets comprises:
• determining whether a BBFRAME has capacity to accommodate the bits of the plurality of data packets;
• when the BBFRAME has capacity, assigning the bits to the BBFRAME;
• and
• when the BBFRAME does not have capacity and a dwell time is not filled, assigning the bits to an adjacent BBFRAME in the sequence of BBFRAMEs;
• and
• determining a sequence of data packets of the plurality of data packets to be arranged within the sequence of BBFRAMEs in accordance with the assigning of the bits to the BBFRAMEs, and outputting the sequence of data packets to a buffer for arrangement as a transport stream comprising the sequence of BBFRAMEs,
• wherein the assigning of the bits to the BBFRAMES optimizes the sequence of data packets for transmission during the dwell time of a beam hopping schedule of a communications system using a predetermined number of symbols, and wherein a required MODCOD is contained within each data packet of the plurality of data packets.