Effect of noise suppression in channel estimation for single-carrier FDMA radio access with variable transmission bandwidth

This paper proposes a two-step noise suppression method in the frequency and time domains for frequency domain channel estimation in single-carrier (SC)-FDMA radio access using a variable transmission bandwidth. In the proposed method, a weighted coherent averaging filter suppresses the noise component of the estimated channel gain in the frequency domain and then, after conversion of the channel gain into a time domain signal, effective path selection with threshold detection suppresses the noise component further. Computer simulation results show that the channel estimation with weighted coherent averaging in the frequency domain in addition to path selection employing threshold detection in the time domain improves the block error rate (BLER) by approximately 0.5 dB compared to that with path selection in the time domain only when the transmission bandwidth is one resource block (RB), i.e., 180 kHz, to four RBs, where paths are not sufficiently resolved. We also confirm that frequency domain channel estimation using only the threshold based path selection improves the BLER performance the most in a wide transmission bandwidth such as 25 RBs where sufficient path resolution accuracy is obtained.