Radio-over-fiber (RoF) systems which act as backbone networks are very promising means of reducing overall costs of 60 GHz WPANs, as well leading to networks with limited intercellular interference. The main objective of this paper is to compare the performance of two different Optical Single Sideband strategies in a 60 GHz OFDM-RoF system, in terms of inter-subcarrier distortion and robustness against dispersion. The comparative study presented here also includes practical impairments such as a finite extinction ratio in Mach-Zehnder modulators and system-added noise. Keywords: radio over fiber, orthogonal frequency division multiplexing, 60 GHz, fiber chromatic dispersion, optical single sideband modulation, inter-subcarrier interference, symbol error rate. INTRODUCTIONThe abundant unlicensed spectrum around 60 GHz offers potential for multi-gigabit indoor Wireless Personal Area Networks (WPANs), IEEE802.16 WIMAX and wireless high definition video services (wirelessHD), removing the bandwidth limitations of current wireless networks. Recently, it was demonstrated that it is possible to produce low cost CMOS components and circuits operating at 60 GHz, as well as the wireless transmission of uncompressed broadband HDTV channels at 60 GHz [1][2]. These advances, combined with the increasing consumer demands for high-speed multimedia data communications are driving intense research on this area and international standard bodies such as IEEE 802.15.3c working group [3]. The transmission of 60 GHz wireless signals is limited to few meters, which implies the deployment of multiple radio access points to cover a single house or building. Conventional coaxial cables are, due to their insufficient bandwidth and high loss, inadequate for transmission of multi-gigabit 60 GHz signals. Therefore, radio-over-fiber (RoF) systems, which act as backbone networks are very promising means of reducing the overall cost of 60 GHz WPANs, as well leading to networks with limited intercellular interference.For the high data rates of broadband wireless systems, we can have severe time-dispersion effects associated to the multipath propagation. Multicarrier (MC) modulation schemes combined with frequency-domain receiver implementations, especially the ones belonging to the orthogonal frequency division multiplexing (OFDM) class are widely used in several broadband wireless communication systems which have to deal with strong frequency-selective fading channels; as such, they are considered a good contender for this application. However, the optical distribution of mm-wave signals with high bit rate is susceptible to fiber chromatic dispersion, which severely limits the transmission distance. This shortcoming can be mitigated using optical single-sideband (OSSB) modulation. Furthermore, OFDM is very sensitive to optical modulator nonlinearities; as such, a linear optical modulator like a single-arm Mach-Zehnder Modulator (MZM) is frequently used to overcome this effect [4] [5]. Unfortunately, this modulator generates an Optical Double Sid...

Part 17: TelecommunicationsInternational audienceRadio-over-Fiber (RoF) systems which act as backbone networks are very promising means of reducing overall costs of 60 GHz WPANs, as well leading to networks with limited intercellular interference. The main objective of this paper is to compare the performance of two systems that generate Optical Single Side Band (OSSB) OFDM signals at the mm-wave band with and without optical up-conversion. Both systems use a DD-MZM: one is a standard model, whereas the other is a DD-MZM cascaded with a phase modulator (PM). The comparative study presented here also includes practical impairments such as the finite extinction ratio of DD-MZMs

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