Short Prototype Filter With Constrained Frequency Spreading for OQAM/FBMC Systems

In this letter, we propose a short filter (i.e., the overlapping factor is one) with constrained frequency spreading (CFS) for offset quadrature amplitude modulation-based filter bank multicarrier (OQAM/FBMC) systems. In detail, a system of equations in the filter's frequency coefficients is formulated and solved in the sense of least squares, then the filter is obtained through an inverse discrete Fourier transform. Simulation results reveal that the proposed CFS filter is able to achieve comparable performance to existing short filters in the presence of different channel impairments with less frequency spreading, which leads to lower implementation complexity of OQAM/FBMC using frequency spreading structure, thus it is a valuable choice when considering both the CFS and a near perfect reconstruction of the OQAM/FBMC signal.