nal significantly decreases; however, the signal processing complexity and latency prohibitively increases relative to that of the OFDM processing. go(t) exp [j2nt(f-mT)] g1(t) x(t)= S(N-2)m gn-2(t) exp [/27t(N-1)Af(t-mT)] XN-1 (t) = g(t-mT)exp[j2u(N-1)Af(t -mT)] S(N-1)m gn-1(t) Figure 3.20 Illustration of FBMC concept and transmitter/receiver architecture [47]. 340 Chapter 3 FBMC signal in the frequency domain (K = 3) FBMC signal in the frequency domain (K = 2) OFDM signal in the frequency domain FFT bins Figure 3.21 Comparison of OFDM and FBMC signals in the frequency domain [38]. 3.2.3.3 Universal Filtered Multicarrier Universal filtered multicarrier (UFMC) is a generalization of OFDM and FBMC. The ulti- mate goal of UFMC is to combine the advantages of OFDM and FBMC while avoiding their main drawbacks. By filtering groups of adjacent subcarriers, the side-lobe levels (com- pare to OFDM) and the prototype filter length (compare to FBMC) can be simultaneously and significantly reduced. The kth OFDM signal over the ith physical resource block (i.e., 12 adjacent subcarriers in NR) can be expressed as follows [38]: m = 0, , Nsub where Si is a set which contains consecutive subcarrier indices that are assigned to the ith physical resource block. This signal is then filtered by an FIR-filter fi(n) with the length of New Radio Access Physical Layer Aspects (Part 1) 341 LF. The UFMC scheme applies filtering on a per subband basis, reducing complexity of the baseband processing algorithms. Thus, the kth transmit symbol can be written as The FIR-filter can be differently designed for each physical resource block. Let's assume that we use an identical Chebyshev filter with variable side-lobe attenuation for all physical resource blocks and the filter is shifted to the center frequencies of the physical resource blocks. The filter ramp-up and -down regions at the beginning and the end of individual UFMC symbols provide somewhat ISI protection, in the presence of channel delay spreads and timing offsets. With very high del