Filtered decision feedback channel estimation for OFDM-based DTV terrestrial broadcasting system

An investigation into time-domain approach for OFDM channel estimation

“…In this section, we relate the proposed MST method to the DFT-based approaches [15], [16], [10]. Essentially, due to the one-to-one relationship of DFT and IDFT, the MST method can be related to DFT-based approach as shown in Fig.…”

“…Similarly, time domain interpolation can be performed at the cost of complexity. Most of the channel estimation approaches may be viewed as DFT-based approaches [15], [16], [10], [11], where LS (Least square) channel (frequency response) estimates are fed to IFFT block to get time domain channel impulse response estimate, and then appropriately processed and transformed back to frequency domain by FFT. A DFT-based approach for OFDM system with transmit and receive antenna diversity has been discussed in [10].…”

Multi-user OFDM employing parallel interference cancellation assisted decision-directed channel estimation

“…as for example QPSK we have α = 1, while for higher-order Quadrature Amplitude Modulation (QAM) schemes we have α > 1 [4]. In the context of the derivation of Equation 7 we have exploited that the complex symbols transmitted by different users in the same subcarrier are statistically independent, which also implies that they are uncorrelated, i.e.…”

“…The factor ρ was termed in [4] as the "filter noise reduction factor". The MSE of Equation 7 can therefore be modified to yield:…”

“…In order to further improve the channel transfer function estimator's MSE, a well-established approach [4,5] is to apply Fast Fourier Transform (FFT) based time-domain windowing to theá posteriori estimated channel transfer factorsĤ…”