We present a high-speed integrated fiber-wireless system in the W band for transmission of high- frequency radio signals to ultra-dense small cells and moving cells. The system utilizes a wavelength-division-multiplexing intermediate- frequency-over-fiber system and a remote generation and transmission of local oscillator signals. We experimentally confirmed satisfactory performance for the transmission of 4 Ã- 25-Gb/s and 20-Gb/s OFDM signals over a fixed and a switchable system, respectively. The system is highly spectral efficiency and scalable for signal transmission in future mobile networks.