A Pilot-Aided Multicode CDMA Transmission Over Wireless Channels

To adapt to the time-varying multipath fading associated with the wireless link, we address the use of a pilot-aided fade-resistant transmission scheme based on the multicode code division multiple access (CDMA) technology. In this system, all the information symbols along with the pilot symbol of a user are transmitted simultaneously over the wireless channel. We apply matched filter receivers to estimate time-varying multipath channel coefficients and the contribution of the pilot signals is subtracted from the received signal prior to decoding the information symbols. We analyze the tradeoff between the number of diversity branches and the channel estimation error in the performance. Our study indicates that, depending on the transmitter power and the channel condition, the proposed system is capable of outperforming the conventional CDMA system with known channel state information at the receiver.