Efficient channel estimation for LTE uplink

In this paper we propose efficient channel estimation for Long Term Evolution (LTE) uplink multi-user (MU) over frequency-selective fading multiple-input multiple-output (MIMO) channels. By exploiting the properties of reference signals (RS), we find a special form of signal model. Based on the special form, firstly, we propose a low complexity spline interpolation based channel estimator. Then, to improve the interpolation performance we propose a new extendible inverse discrete cosine transform (EIDCT) and a DCT/EIDCT-based approach. For their limited performance, we derive a more accurate channel estimator based on the DCT/EIDCT approach with low-complexity implantation. In two DCT/EIDCT-based estimators, signal first performs DCT, then optimal channel estimation in least square (LS) and linear minimal mean square error (MMSE) in DCT-domain is derived respectively. After obtaining the DCT-domain parameters, the new EIDCT gives accurate recover of signal. Finally, the performance of the proposed channel estimation is verified via simulation.