An Improved Chip Detector for OFDM-IDMA over Fast Time-Variant Channels

We analyze the performance of an orthogonal frequency-division multiplexing interleave-division multiple access (OFDM-IDMA) system over a fast time-variant channel. First we introduce a vector-valued transmission model of a classical OFDM-IDMA system over time-invariant channels. Consecutively, this vector-valued transmission model is used to analyze the effect of fast time-variant channels on an OFDMIDMA system. Based on this, a modified receiver principle with only a moderate increase in complexity is given. Finally, simulation results show that the performance of OFDM-IDMA over fast time-variant channels is improved substantially by the new receiver concept.