Pilot-Assisted Channel Estimation for Multipath DS-CDMA Systems: Frequency Domain Channel Equalization in Space-Time Clock Codes

Multiuser detection using frequency domain equalization (FDE) in space-time block coded DS-CDMA with transmit diversity is addressed in this book. The space time transmit diversity techniques, along with FDE have been shown to provide an efficient means of achieving improved bit error rate performance in frequency selective fading channels, using frequency diversity techniques. A subcarrier by subcarrier based linear MMSE-FDE is carried out for diversity combing and decoding of user information. Finally, The BER performance of the proposed approach is evaluated by computer simulations. For these systems, perfect knowledge of channel state information is required for diversity combining and decoding at the receiver end. Hence, a low complexity, bandwidth efficient frequency domain based pilot assisted channel estimation technique for block faded space time transmit diversity DS-CDMA system is proposed. For which, a two transmit and one received antenna based transmit diversity scheme, proposed by Almouti are considered.