Performance of Iterative Multiuser Detection With Channel Estimation for MC-IDMA and Comparison With Chip-Interleaved MC-CDMA
This paper applies iterative multiuser detection employing new channel estimation to MultiCarrier InterLeave Division Multiple Access (MC-IDMA), known as OFDM-IDMA, which is expected to improve spectral efficiency in mobile communications. The MC-IDMA transmitter uses both a low-rate channel code and an individual chip interleaver for each user. The MC-IDMA receiver, which this paper investigates, repeats the iterative multiuser detection and Soft Decision-Directed Channel Estimation (SDCE) by exploiting Log-Likelihood Ratios (LLRs) of the coded bits which the MAP-based channel decoders for all users provide. SDCE estimates channel impulse responses of all users by the LMS algorithm, which aims to minimize the mean squared error between the received signal and its replica.