Channel estimation for LTE downlink using RLS-based threshold judgement

Accurate channel estimation is one of the significant technologies to improve the coherent demodulation performance for orthogonal frequency division multiplexing (OFDM). Based on the recursive least square (RLS)-based threshold judgement, a joint estimation algorithm for long term evolution (LTE) downlink is proposed in this paper. Using the frequency domain pilots, we use the least squares criterion to estimate the channel impulse response, track the channel by RLS method, and suppress the noise within the length of cyclic prefix in time domain. Based on the comparisons of the BER, MSE and running time for the joint estimation, least squares (LS), traditional discrete Fourier transform (DFT), threshold-based DFT and LMMSE in the conditions of the low signal to noise ratios (SNR), the efficiency and effectiveness of the joint estimation algorithm are verified in the aspects of gain and computation cost.