Adel Abbasi - Department of Electrical Engineering, Boushehr Branch, Islamic Azad University, Boushehr, Iran
Navid Daryasafar - Faculty of Electrical Engineering, Dashtestan Branch, Islamic Azad University, Borazjan, Iran

The aim of this paper is to investigate channel estimation methods based on adaptive methods in MIMO-OFDM systems. In this paper, least mean square (LMS) and recursive least squares (RLS) adaptive channel estimator are described for multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. These CE methods uses adaptive estimator which are able to update parameters of the estimator continuously, so that the knowledge of channel and noise statistics are not necessary. First of all, pilots were inserted among subcarriers in transmitter with distances emerged of sampling theory then Least-Square method was chosen for initial channel estimation in pilots at receiver. The simulation results showed that the RLS CE algorithm is better to use for MIMO OFDM systems.

Multi-Input Multi-Output systems, Cyclic prefix (cp), Channel estimation, LMS estimator and RLS estimator