T and SMT channel tracking is possible without any use of pilot symbols. 5.5.3 Timing Tracking As noted above, any difference between the clock frequency at the transmitter and its coun- terpart at the receiver introduces a timing drift. The common method of compensating for this timing drift is to add a timing recovery loop to the system. In a single carrier receiver, the addition of a timing recovery loop as part of the receiver processing is a relatively straight- forward task and is well understood; e.g. see [19]. In an OFDM system, with a not very long payload, the timing drift may be absorbed by the cyclic prefix (CP), provided that not the full length of the CP has been consumed by the channel transient response. Drift of tim- ing phase introduces a linear phase across frequency and that can be easily compensated by the single-tap equalizers at the fast Fourier transform (FFT) outputs. In FBMC, on the other hand, the absence of CP/guard interval makes an FBMC receiver more sensitive to timing drift. However, fortunately, this problem can be resolved trivially through the use of a set of multi-tap fractionally spaced equalizers, one per subcarrier. For more details, the interested reader may refer to [8]. 5.6 Equalization In FBMC receivers, equalization is performed at the output of the AFBs. It is often assumed that each subcarrier has a small bandwidth, and hence the channel may be assumed flat over each subcarrier band. In that case, a single-tap equalizer per subcarrier would suf- fice. In cases where the flat gain approximation may be insufficient, a multi-tap equalizer per subcarrier band may be necessary. For CMT and SMT systems, it is necessary to use a fractionally spaced equalizer. A tap-spacing of half symbol interval is the most convenient choice, and hence has been suggested in the literature, e.g. [33]. Although, in many scenarios, it may appear that a single-tap equalizer per subcarrier is sufficient, in practice, where carrier and clock mismatch between the transmitter and receiver is inevit