modem system includes the steps of encoding the data using forward error correction the data is then encoded with turbo encoding the data is then sent to a modulation scheme the data is then transmitted over a cable channel the data is then demodulated the data is then decoded using a turbo decoder an inverse of the forward error correction is then applied to the data application_number US 84355810 A description reference will now be made in detail to the preferred embodiments of the present invention examples of which are illustrated in the accompanying drawings fig1 is a block diagram of a cable modem communication system 100 including a headend baseband modulator demodulator u201c headend u201d 102 that communicates with a plurality of cable modulators demodulators u201c modems u201d 104 through a primary cable 106 which branches to user cables 108 the cable modems 104 demodulate data from the headend 102 and modulate data to be transmitted to the headend 102 one or more optional intermediate power amplifiers 110 can be placed along the cables 106 and or 108 to boost signal strength the cables 106 and 108 have less impairments compared to wireless communication systems the relatively low noise the optional intermediate power amplifiers 110 and relatively short distances involved provide the cable modem communication system 100 with a relatively high signal to noise ratio u201c snr u201d the communication paths from the headend 102 to the users 104 are called down stream paths or channels the communication paths from the users 104 to the headend are called up stream paths or.