A full-duplex radio over fiber (RoF) link with the generation of a 64-GHz millimeter wave (mm-wave) is investigated. This system is proposed as a solution to cope with the demands of a data transmission in the fifth generation (5G) and beyond for small cell networks. Cost reduction and performance improvement are achieved by simplifying the mm-wave generation method with an RoF technique. High-frequency radio signals are considered challenging in the electrical generation domain; therefore, our photonic generation method is introduced and examined. RoF design is proposed for mm-wave generation using both phase modulation and the effect of stimulated Brillouin scattering in the optical fiber for the first time. RoF system with transmission rates of is successfully achieved. In our scheme, one laser source is utilized and a fiber Bragg grating is used for wavelength reuse for the uplink connection. Stable mm-wave RoF link is successfully achieved in up to a 100-km fiber link length with high quality carrier. Simulation results show a reduction in fiber nonlinearity effects and the mm-wave signal has low noise equal to . This study ensures a practical mm-wave RoF link, and it could be appropriate for small cell 5G networks by reducing the installation cost.