Iterative Interference Suppression for High-Rate Single-Carrier Space-Time Block-Coded CDMA

In this paper, we employ time-reversal space-time block coding (TR-STBQ in single-carrier direct sequence code- division multiple access (DS-CDMA) block transmission in the presence of multiple access interference (MAI) as well as intersyrnbol interference (ISI), which is subject to fairly long delay spread. We introduce the transmission rate improvement by capitalizing on the assignment of additional spreading codes to each user so as to expand the cardinality of space-time code matrix. Given perfect channel state information at the receiver, a simple linear frequency-domain interference suppression scheme on a basis of symbol-by-symbol processing is developed under certain circumstances. A soft receiver is facilitated by exploiting the serially concatenated structure at the transmitter to further enhance system performance. Simulation results justify the efficacy of our proposed system and also present performance comparison with well-known OFDM systems in terms of bit error rate (BER).