Filter Optimization for Carrier-Frequency- and Timing-Offset in Universal Filtered Multi-Carrier Systems

Universal Filtered Multi-Carrier (UFMC) is a novel multi-carrier modulation technique which can be seen as a generalization of filtered OFDM and filter bank based multicarrier (FBMC-FMT). Being a candidate waveform technology for 5G wireless systems, it combines the simplicity of OFDM with the advantages of FBMC. The FIR-filter, used in UFMC to filter a group of subcarriers, is a key design parameter to gain more robustness in relaxed synchronization conditions, i.e. timefrequency misalignment. It was shown in previous work that very significant SIR improvement can be achieved for UFMC by optimizing the FIR-filter, taking carrier frequency offset into account. In this paper, we optimize the FIR-filter design in UFMC by taking both carrier frequency and timing offset into account in an uplink multi-user FDMA scenario. From the simulation results, up to 3.6 dB SIR improvement can be achieved with the optimized FIR filter compared to UFMC with non-optimized Dolph-Chebyshev filter and 15.1 dB SIR gain against classical CP-OFDM system respectively, provided that the normalized carrier frequency and timing offset are uniformly distributed in the interval ±5%.