Broadband Wireless Access

In future cellular radio networks Radio over Fiber (RoF) is a very attractive technology to deliver microwave and millimeter-wave signals containing broad band multimedia services to numerous base stations of the network. The radio signals are placed on an optical carrier and distributed by means of an optical fiber network to the base stations (BS). In the BS the optical signals heterodyne in a photodiode to produce the radio signals which are then sent via a wireless link to the mobile units (MU). The optical fiber network provides high frequency, wideband, low loss and a means of signal distribution immune to electromagnetic interference. The generation of an optical double-sideband with suppressed carrier (DSB-SC) signal is a straightforward method due to the fact that only one microwave modulator driven at half the millimeter-wave frequency is required. One sideband is modulated with baseband data rates of up to 10 Gbps. Transmission experiments prove this modulation scheme to be dispersion tolerant and error free transmission was demonstrated after 40 km of single mode fiber for data rates up to 5 Gbps. The limits of the setup were tested with data rates of 10 Gbps.