lly distributed (i.i.d.) with E o's is the average transmission power of QAM symbols. The transmitter and receiver procedures are described as follows: (1) Inverse fast Fourier transform (IFFT) and CR appending. An N-point (N > M) IFFT operation is performed on per OFDM symbol basis, followed by the addition of a CR of length Ncr for eliminating/mitigating ISIs. The CR is made up of two parts, cyclic prefix (CP) of length Ncp and cyclic suffix (CS) of length Ncs (Ncr = Ncp + Ncs). To be compat- ible with CP-OFDM, CR can be implemented as an extended CP that incorporates CP and CS at the transmitter, and the FFT window at the receiver is moved forward by the length of CS. The CP is adopted for combating the ISI induced by the dispersive nature of channels and the ISI introduced by filter forward spreading, while the CS focuses on the alleviation of the ISI induced by the filter backward spreading. The k-th OFDM symbol can be expressed in the form of matrix multiplication as (2.2) where XK is a vector of dimension L = N + F is an N x M submatrix of N-point IFFT matrix defined by its element on the n-th row and m-th column as it is unitary = = is the N matrix inserting the CP and CS, with Icp and ICS containing the last and the first 1 Interested users are referred to [21], which gives a thorough analysis on inter-subband interference. 2 Filtered OFDM: An Insight into Intrinsic In-Band Interference Ncp rows of the identity matrix IN, respectively. Pcr is the power normalization factor defined as Pcr N/L. (2) Transmitter filtering. By applying a spectrum shaping filter, the actual transmitted f-OFDM signal is obtained as S X * p, (2.3) where = and (2.4) is a length Np + vector describing the impulse response of the transmit filter. The filter is designed to be centered in the assigned subband with a width equivalent to the bandwidth of the subband. N, is typically chosen as (1) an even number SO that the time domain symmetry of the filters is ensured, (2) less than or equal to half of the FFT size, i.e. N p N/2 to ke