Low complexity downlink channel estimation for LTE systems

The 3rd generation partnership project (3GPP) long term evolution (LTE) is designed for high speed data rate, higher spectral efficiency, improved services, and lower latency as well as high-capacity voice support. LTE uses orthogonal frequency division multiplexing access (OFDMA) scheme for the downlink transmission and single carrier frequency division multiple access (SCFDMA) in uplink. Main challenges for a terminal implementation are efficient realization of the inner receiver, especially for channel estimation (CE) and equalization. In this paper, a new channel estimator is presented for an OFDMA system under the umbrella of the 3GPP LTE that can avoid the ill-conditioned least square (LS) problem. This channel estimation method uses knowledge of channel properties to estimate the unknown channel transfer function at non-pilot sub-carriers. Therefore, the computational complexity can be reduced significantly.