Coded orthogonal frequency division multiplexing for wireless ATM

The performance of the concatenated inner trellis coded modulation (TCM) and outer Reed Solomon (RS) code with orthogonal frequency division multiplexing is evaluated in a frequency selective fading channel for wireless ATM (WATM). A 512 carrier OFDM is selected to facilitate the transmission of ATM cells of 155 Mb/s rate, in a frequency selective fading channel, while the high gain concatenated scheme is selected for an improved error performance. An interleaver of depth four is introduced at the output of the RS outer coder to randomize the burst errors from the TCM decoder, while a channel interleaver is also introduced to combat the correlated fading of the channel. The investigated concatenated coding scheme is capable of achieving a bit error rate of 10^-5 at an average Eb/No of 14 dB. The result is also compared with that of a convolutional code (CC) with constraint length seven using 16-QAM modulation