Multicarrier code division multiplex with iterative MAP symbol-by-symbol estimation

In this paper we consider a Multi Carrier Code Division Multiplex (MC–CDM) scheme. At the receiver side the Maximum A Posteriori Symbol–by–Symbol Estimator (MAPSSE) is used for the detection of the CDM signal. Therefore the influence of the spreading factor on the overall Bit Error Rate (BER) is investigated. We concatenate the MAPSSE with the channel decoder which allows for iterative decoding. This system can be considered as a serially concatenated iterative decoding scheme whereby the inner decoder is replaced by the MAPSSE. Therefore the bit error rate can be further reduced by means of iterative decoding. A combination with an inner Recursive Systematic Convolutional (RSC) component code with rate 1 is suggested to further improve performance. The applications are broadcasting and with some extensions two way communications. Keywords—OFDM, CDMA, iterative decoding