 frequency-domain filter W(k) is the DFT of the corresponding time-domain impulse response w(n). The equalized frequency-domain signal is then transformed to the time domain using an inverse-DFT operator. For processing of each signal block of size N = 2m. the frequency-domain equalization would include two N-point DFT/IDFT operations and N complex multiplications. With the introduction of a CP, the channel would appear as a circular convolution over a receiver processing block of size N. Therefore, there would be no need for overlap- and-discard in the receiver processing. Furthermore, the frequency-domain filter taps can now be calculated directly from an estimate of the sampled channel frequency response. Similar to the OFDM case, the drawback of using CP in conjunction with single-carrier transmission is the overhead in terms of extra power consumption and bandwidth. One method to reduce the relative CP overhead is to increase the block size N of the FDE. However, the accuracy of block equalization requires that the channel to be approximately constant over a period of time corresponding to the size of the proces- sing block. New Radio Access Physical Layer Aspects (Part 1) 333 Equalizer Detector Equalizer Detector DFT-S-OFDM Figure 3.15 Illustration of different equalization/detection aspects of DFT-S-OFDM and OFDM [30]. The detection procedure for a DFT-S-OFDM signal is illustrated in Fig. 3.15 and is com- pared with that of an OFDM waveform. The transmission through a time-dispersive or equivalently a frequency-selective channel will distort the DFT-S-OFDM signal and equalizer shown is needed to compensate for the effects of channel frequency selectivity. However, an as in Fig. 3.15, a simple one-tap equalizer can be applied to each subcarrier in OFDM, whereas in the case of DFT-S-OFDM, the frequency-domain equalization function prior to the IDFT operation. is applied to the complex-valued symbols at the output of the subcarrier demapping and It order must be noted that in OFDM downlink parameterization, t