An apparatus, comprising: a frequency-domain receiver comprising circuitry which operates with at least two different subcarrier spacings, one for data channels and another one for control channels, where subcarrier spacing of a portion of a time-frequency space containing the control channels is B times as large as the subcarrier spacing of a portion of the time-frequency space containing the data channels, wherein B is an integer greater than one, and wherein the circuitry is configured to perform operations comprising: receiving N time samples during a data transmission and N time samples during a control transmission, separating the N samples received during the control transmission into a number of time-domain sub-blocks that is greater than or equal to B, processing the N samples in the number of time-domain sub-blocks to create a same number frequency-domain sub-blocks, wherein the frequency-domain sub-blocks have a size of N divided by the number; processing the number of frequency-domain sub-blocks to determine decoded control bits; and outputting the decoded control bits, wherein the circuitry comprises a single receive chain comprising a first fast Fourier transform having a first size corresponding to a first subcarrier spacing for the data channels, and the circuitry is configured to compute, by using the first FFT, a second FFT having a second size corresponding to a second subcarrier spacing for the control channels, wherein the first and second sizes of the first and second FFTs are different sizes, wherein the first FFT is an N- point fast Fourier transform and the number of time-domain sub-blocks is B, and wherein the circuitry is configured to perform an operation of mapping the number of time-domain sub-blocks to different time samples of the N- point FFT in a comb structure, where the N- point FFT is used to create the number of N / B -sized frequency-domain sub-blocks, wherein mapping comprises performing an operation of shifting a first block of symbols, which are initially aligned in frequency in a time-frequency space with a second block of symbols, to be interleaved with the second block of symbols and combining a resultant number of time-domain sub-blocks to create data applied to the N -point FFT. a frequency-domain receiver comprising circuitry which operates with at least two different subcarrier spacings, one for data channels and another one for control channels, where subcarrier spacing of a portion of a time-frequency space containing the control channels is B times as large as the subcarrier spacing of a portion of the time-frequency space containing the data channels, wherein B is an integer greater than one, and wherein the circuitry is configured to perform operations comprising: receiving N time samples during a data transmission and N time samples during a control transmission, separating the N samples received during the control transmission into a number of time-domain sub-blocks that is greater than or equal to B, processing the N samples in the number of time-domain sub-blocks to create a same number frequency-domain sub-blocks, wherein the frequency-domain sub-blocks have a size of N divided by the number; processing the number of frequency-domain sub-blocks to determine decoded control bits; and outputting the decoded control bits, wherein the circuitry comprises a single receive chain comprising a first fast Fourier transform having a first size corresponding to a first subcarrier spacing for the data channels, and the circuitry is configured to compute, by using the first FFT, a second FFT having a second size corresponding to a second subcarrier spacing for the control channels, wherein the first and second sizes of the first and second FFTs are different sizes, wherein the first FFT is an N- point fast Fourier transform and the number of time-domain sub-blocks is B, and wherein the circuitry is configured to perform an operation of mapping the number of time-domain sub-blocks to different time samples of the N- point FFT in a comb structure, where the N- point FFT is used to create the number of N / B -sized frequency-domain sub-blocks, wherein mapping comprises performing an operation of shifting a first block of symbols, which are initially aligned in frequency in a time-frequency space with a second block of symbols, to be interleaved with the second block of symbols and combining a resultant number of time-domain sub-blocks to create data applied to the N -point FFT.