Data transmission scheme using channel group and DOCSIS implementation thereof

A novel apparatus for and a method of data transmission whereby an input data stream is distributed over a plurality of physical channels within a logical channel group. Transmission of data over the channel group appears as transmission over a single logical channel having a bandwidth approximately equal to the sum of the physical channel bandwidths. The physical channels making up the logical channel group may have different bandwidth capacities. The invention comprises a method of data unit distribution among a plurality of physical channels including the consideration of the bandwidth capacities of the individual physical channels in implementing the distribution algorithm, and the capability of reproducing the order of the transmission of the data units on the receiving side without the need for additional fields or modification of existing fields of the data units. The method of the present invention performs an algorithm whereby the transmitter and the receiver only need to decide to transmit/receive a data unit using the current channel or to switch to the next channel in the channel pool (i.e. the channel group). This decision is made considering the value of a bandwidth parameter and current 'credit' counter associated with each channel.