Multicarrier Spread Spectrum Performance in Fading Channels with Serial Concatenated Convolutional Coding

We study a multicamier direct sequence code division multiple access (CDMA) system combined with the recently discovered interleaved serial concatenated convolutional codes. This combination of modulation method and coding scheme provides great flexibili~ in obtaining a particular bit error rate performance. With interleaved serial concatenated convolutional codes, in which an interleave is situated between two convolutional codes connected in series, coding gain can be altered by changing the size of the interleave, or by changing the rate or constraint length of either of the two constituent codes. With a multicarrier direct sequence CDh4A system, frequency diversi~ can be obtained by spreading the code symbols across the carriers, and by using repetition coding. The number of carriers and the processing gain can be altered as well to achieve a particular performance goal. In addition, frequency diversity can be traded for data rate by parallel transmission of information symbols. This paper characterizes system performance so that intelligent tradeo~s can be made in system design. Emphasis is on terrestrial communication in fading for a personal communication system.