Regularized Recursive Least Square-Based Time Domain Iterative Channel Estimation Scheme for OFDM-IDMA Systems

In the recent time, there have been investigation efforts into time domain channel estimation techniques, exploiting underlying sparseness in OFDM channel, for multiuser-based orthogonal frequency division multiplexing-interleave division multiple access (OFDM-IDMA) systems. This paper developed and proposed a new channel estimation algorithm for the OFDM-IDMA systems. This is called regularized correlated time-averaged-based variable forgetting factor recursive least square (RCTVFF-RLS)-based channel impulse response (CIR) estimator. The performances of the proposed estimator are compared with the performances of some previous estimators in literature with the aid of computer simulation. It is found that the proposed RCTVFF-RLS-based CIR estimator outperforms all the other estimators considered in this paper, and these performances are documented for the system operating under fast and slow fading channel scenarios. However, the proposed estimator exhibits higher computational complexity than the poorest performing estimator considered in this paper. Its computational complexity is in the same neighborhood with some closely performing estimators considered.