The heterogeneous services and the demands for higher data rates, in addition to the need to reduce interference and increase system spectrum efficiency (SE), a new adaptable waveform has been suggested for the physical layer of the Fifth Generation (5G) system. The Filtered-Orthogonal Frequency Division Multiplexing (F-OFDM) waveform is proposed to satisfy the requirements of the new generation, allowing for asynchronous transmissions between the users and increasing system SE. F-OFDM splits the assigned band into smaller subbands with different configurations based on the service requirements. Each subband is filtered separately, and different types of specifications are accommodated in the filters utilized. Two scenarios were adopted in the design of F-OFDM, equal and unequal subband sizes using LabVIEW NXG Software and Matlab simulator. The simulation results show that F-OFDM with various designed window-sinc filters achieves lower Out-Of-Band Emission (OOBE) than conventional OFDM. The subbands waveform has a significant effect on the SE (5%-6%) higher compared to the conventional OFDM by decreasing the guard band. Practical implementation of the proposed waveform in an indoor environment using the Universal Software Defined Radio Peripheral (USRP) X310 platform for spectrum confinement testing in real time is presented at (2.45 GHz). The obtained output spectrum shows that a minimum guard band between the subbands can be achieved by lowering the OOBE in comparison to OFDM.