A 60 GHz Radio-over -Fiber Architecture for the Transmission of UWB- OFDM Signals Mostafa Benzazaa 1 , Frédérique Deshours 1 , Catherine Algani 2 , Florent Mandereau 2 , Georges Alquié 1 , Anne-Laure Billabert 2 1 UPMC UNIVERSITE PARIS 06, L2E, 3 rue Galilée, 94200 Ivry-sur-Seine, France 2 ESYCOM-CNAM, 292 rue Saint-Martin, 75141 Paris Cedex 3, France mostafa.benzazaa@upmc.fr Abstract — This paper presents an original 60 GHz architecture for Ultra-Wide Band (UWB) Radio-over-Fiber (RoF) systems to increase both the transmission distance and the high data bit rate. With a Central Station (CS) and a Base Station (BS), this architecture allows to send through an optical fiber both a subcarrier microwave signal and UWB baseband data by using a wavelength multiplexer. At the BS, the carrier frequency is photodetected, modulated by data and then up-converted to millimeter-wave band. Simulation results using VPIsystems software are reported and discussed for Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) signals. Index Terms — Millimeter-wave, Radio-over-Fiber, Ultra-Wide Band, Multi-Band Orthogonal Frequency Division Multiplexing I. INTRODUCTION Wireless home services increase faster and faster and they need the deployment of a large number of wireless nodes embedded in every day life objects to create ideally a dynamic and self organized ad hoc network [1]. With the incoming of high data rate communication protocols for wireless networks such as IEEE 802.15.3a, 60 GHz Radio Frequency systems are a current alternative to Ultra-Wide Band (UWB) technologies limited by power regulations [2]. In this way, several 60 GHz Radio-over-Fiber (RoF) systems have demonstrated interesting performances [3]-[6]. The millimeter-wave band presents several advantages, such as large spectral capacity, small used antennas, compact and light equipment. An additional benefit results from reduced co-channel interferences due to the high level of the oxygen absorption (10-15 dB/km in the 60 GHz band). Orthogonal Frequency Division Multiplexing (OFDM) has found its way as fiber-wireless indoor wideband communication systems due to its robustness in multi-path channels, immunity to fading channels and tolerance of delay spread [7]. Thus, introducing OFDM modulation in optical fiber, the millimeter-wave band in RoF system can be used not only for short distance but also for long-range transmission at very high data rate [8]. So, this increases the flexibility of the system and provides a very large coverage area without increasing its cost and complexity very much. This paper, following the work presented in [9], reports a development of an original 60 GHz fiber radio system based on the IF-over-Fiber technique. The aim of this architecture is to increase the system transparency to digital modulation schemes and to prevent the chromatic dispersion inherent in 1.55 μm standard Single Mode Fibers (SMFs). It proposes an efficient alternative to millimeter-wave fiber-radio communication systems by reducing the architecture complexity and offering a very cost-effective solution for high data rate distribution at 60 GHz. The topology of the CS is improved and simplified significantly, as it only involves two Distributed-FeedBack (DFB) lasers to perform UWB data and RF carrier transmission. The proposed architecture has been simulated under VPIsystems software using different complex data modulation formats. In this paper, we focus our study on the Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) modulation scheme because it is one of the most suitable technique for high-speed transmission at 60 GHz. In order to check the performances of the fiber-radio system, simulated results are given in terms of Error Vector Magnitude (EVM). II. THE ARCHITECTURE DESCRIPTION The millimeter-wave fiber-radio system involves the use of two microwave signals transmitted through an optical fiber. The first one supports high data rate information (MB-OFDM data). The second one is a 7.5 GHz RF signal with high spectral purity to limit the lowering of the radio communication quality. The 7.5 GHz RF is used as an Intermediate Frequency (IF) for the 60 GHz system. After an optical transmission through a SMF and a demultiplexing, the 7.5 GHz reference signal is created after photodetection. This signal is already modulated by UWB data. It is then multiplied up to 60 GHz. A) Central Station (CS) Configuration Fig. 1 represents the Central Station (CS) schematic considered in the millimeter-wave RoF system. The CS is an optical transmitter that controls and distributes all the signals between fiber-optic networks.