Multicarrier Interleave-Division Multiple-Access Systems with Adaptive Pilot-Based User Interleavers

This paper considers a novel approach to multicarrier orthogonal frequency division multiplexing-based interleave-division multiple-access (OFDM-IDMA) that facilitates both channel estimation and multi-user detection. Specifically, users employ interleavers based upon their channel state information (CSI) to optimize pilot symbol locations, instead of random interleavers as in conventional IDMA. Two variants of this approach are considered: pilot symbols time-multiplexed into the transmit signal after channel encoding, and pilot symbols encoded along with the information bits prior to CSI-based relocation. The encoding of pilot symbols is shown to offer an additional performance benefit at the channel decoders. Simulation results are presented to verify the advantages of the proposed methods with respect to conventional IDMA with uniform and/or uncoded pilot symbols.