Adaptive algorithms based-time domain iterative channel estimation for MC-IDMA systems

Multicarrier-Interleave Division Multiple Access (MC-IDMA) scheme is an attractive Multiuser technique that has generated a large interest in the research community. However, availability of accurate estimate of channel state information (CSI) at the receiver end of the system remains an essential factor in the optimum performance of the whole system. In this paper, two families of Least Mean Square (LMS) Algorithm, namely, Normalized Least Mean Square (NLMS) and Variable Step Size Normalized Least Mean Square (VSSNLMS) algorithms are proposed for implementation of time domain iterative channel estimation for MC-IDMA systems. Channel estimation in time domain is considered in this paper because it has earlier been confirmed that if the number of OFDM subcarriers exceed the number of channel taps, as the case is in most practical OFDM based systems, the time domain channel estimate is more accurate than the channel estimation in frequency domain. The performance of the proposed adaptive algorithms based-time domain iterative channel estimators are validated in comparison with the LMS-based channel estimator proposed earlier in literature.