Abstract

Millimeter-wave (MMW) radio communication technology is attracting for next generation wireless local access network as well as high-speed fixed wireless system (FWS) owing to its broad available bandwidths; the possible capacity would be greater than 10 Gb/s. Particularly in the FWS that is capable for high-speed wireless backhaul for high-speed vehicles such as a Maglev, seamless connectivity between radio and optical fiber networks is indispensable because the high-speed signal could be distributed over the optical network to the remote base stations (BSs) located along with a railway from a central office; the wireless link would be established between the vehicle and each BS [1]. In the scenario, the MMW radio-over-fiber (RoF) technology is one of the promising candidates to realize the seamless conversion between the optical and MMW radio signals with maintaining the waveform of the signals [2,3]. However, the MMW RoF technology might cause low spectral efficiency (SE) in an optical domain because the RoF signal has a bandwidth corresponding to the MMW signal. For distribution of the signal to many remote BSs, the optical signals should be followed to ultra-dense wavelength division multiplexing. Moreover, from the viewpoint of the radio, the SE would be optimized to be compliant with radio regulations. In the paper, we evaluate an intermediate frequency over fiber (IFoF) technique for 90-GHz MMW signal generation with orthogonal frequency division multiplexing (OFDM) to enhance the SE in both optical and radio domains.

© 2015 IEEE