Review on system architectures for the millimeter-wave generation techniques for RoF communication link

Generation of millimeter-wave (mm-wave) signal for radio over fiber (RoF) currently being investigated and studied by many researchers due to the demand of the mm-wave band for future communication system mostly in wireless local area networks (WLANs) applications. RoF is a system where high microwave frequency signals are delivered through optical fiber between the central station (CS) and the base stations (BSs). The use of optical fiber for signal distribution in mm-wave radio communication systems has been widely investigated, since they provide high bandwidths and small cell sizes (picocell). They also offer the potential for the low cost infrastructure needed to develop broadband mobile services. This paper will explain the whole picture of RoF technology followed by RoF link configurations where radio frequency (RF) signal can be transmitted directly over fiber either at the RF or intermediate frequency (IF) signals. The review mainly focuses on the mm-wave generation techniques for radio over fiber including: optical heterodyning, external modulation, optical transceiver, and up- and down-conversion.