Load Adaptation Scheme to Improve the BER Performance of Multi-Block/Multi-Code MC-CDMA System in Frequency-Selective Fading Channel

摘要

Various data rates in mobile communication are required for various multimedia services. The Multi-Code Multi-Carrier Code Division Multiple Access (MC MC-CDMA) system is one solution to support these various data rates and improve BER performance. However, frequency-selective multipathfading channels destroy the orthogonality of spreading code, which causes inter-carrier interference (ICI). This type of interference has been shown to cause severe degradation in BER performance of MC MC-CDMA systems. In this paper, we proposed the Multi-Block MC MC-CDMA (MBMC MC-CDMA) systemto improve BER performance by reducing the ICI in frequency-selective fading channels. The proposed system changes the spreading factor and number of blocks, but the data rates do not change. The BER performance is evaluated through computer simulation according to channel parameters. Thesimulation results show that the MBMC MC-CDMA system produces a much better performance than conventional MC MC-CDMA systems.