erated from a prototype filter with frequency shift equal to the subcarrier spacing as in filtered multitone (FMT) [3]. ICI depends on the overlap between adjacent filters. To elim- inate ICI and retain the orthogonality, the subcarrier spacing can be set larger than the filter bandwidth. With that, the modulation becomes orthogonal FDM. However, spec- tral efficiency in this case is reduced. In order to preserve both orthogonality and spectral efficiency, two approaches emerged during the past years; the first leads to offset quadra- ture amplitude modulation (OQAM)-orthogonal frequency division multiplexing (OFDM) and the other leads to discrete Fourier transform (DFT)-OFDM [4]. In OQAM-OFDM, the prototype filter is designed to have overlap with the adjacent subcarriers. The orthog- onality is - only - maintained at the in-phase and quadrature components of the com- plex data symbols. This is done by delaying the in-phase component by half the symbol period in one channel and vice versa on the adjacent channel [5]. This approach is revised and reintroduced under the name filter bank multicarrier (FBMC) [6]. In the beginning of DFT-OFDM, the complex data symbols are transformed with DFT, and the real part is passed through low-pass filter [7]. Later, similar approach is used with the consideration of complex signal and using inverse discrete Fourier transform (IDFT) under the name dis- crete multitone (DMT) [8], which is nowadays known as OFDM. The prototype filter used in OFDM has a sinc response, which overlaps with more than one adjacent subcarriers. With the introduction of cyclic prefix (CP) to OFDM, which was actually proposed prior to the well-known form of OFDM [9], the frequency-domain processing of CP-OFDM elim- inates the inter-symbol-interference (ISI) introduced between successive OFDM symbols Radio Access Network Slicing and Virtualization for 5G Vertical Industries, First Edition. Edited by Lei Zhang, Arman Farhang, Gang Feng, and Oluwakayode Onireti. © 2021 John Wiley & Sons Ltd. Published 2021 b