buffer in an appropriate format to be fed to the fec unit 63 the fec unit 63 applies a forward error correction algorithm to the data using a known error correction technique such as reed solomon turbo codes or other codes the transceiver 66 in this instance using it as a transmitter spreads the resulting data by the pn sequence modulates the pn spread data with appropriate channel coding per the assigned sub channels 31 and the up converts the result to the desired radio frequency on the receive side of the reverse link that is at the service provider 40 side the transceiver 44 performs a receiver function in this instance the rf down converter 71 feeds multiple receiving units that each include an equalizer 72 a pn code despreader 73 and demodulator 74 each demodulated output is provided to a protocol converter block that includes an fec decoder 75 an inverse segment framer 76 and buffer 77 a controller 78 may be used to control and or implement each of the protocol converter functions as described in further detail below in the preferred embodiment the fec decoder 75 makes use of a so called trellis decoder because a trellis decoder is a type of decoder which compares multiple bits in groups to arrive at an estimate of the correct received bits.