or sending their pilot symbols. A clever method of shortening an FBMC packet, and hence improving on its spectral efficiency, has been proposed in [29]. In this work, the authors have developed a method of adding a few (virtual) symbols at the beginning and the end of each FBMC packet to suppress signal samples at both its starting and ending tail. 5.5.2 Channel Tracking Tracking of channel variation (including variations due to CFO and clock timing drift), during the payload transmission, is usually made through distributed pilots that are transmitted along with the data symbols. This topic, as noted above, has been well studied for OFDM. However, it has received very limited attention in the FBMC literature. Stitz et al. [24] have studied the problem of pilot-aided synchronization and tracking methods in CMT/SMT-type systems. They have shown that by applying specific pilots designed for CMT/SMT, the CFO, fractional time delay (FTD), and channel response can be accurately estimated. The work presented in [30] has taken a different approach. It takes note of the fact that each signal component at the output of the AFB, before performing equalization and taking its real (or imaginary) part, has the form of hk[n](sk[n] + juk[n]) (or where 4k[n] arises from ICI and ISI. It is thus argued that if the same (known) symbol is transmitted over two instants of time at the same subcarrier, or allocated to the real and imaginary parts of an OQAM symbol in an SMT waveform, the analyzed signal samples give a pair of equations that can be solved to obtain an estimate 5.6 Equalization of hk[n]. In a more recent work [31], a coding method that removes 4k[n] from the pilot symbols and thus facilitates the channel estimation has been proposed. In [32], it has been noted that the use of PAM symbols in CMT (and similarly in SMT, if the real and imaginary part of each OQAM symbol is viewed as a pair of PAM symbols) allows development of a blind equalization algorithm. This algorithm may also be used for channel tracking. Hence, in CM