Impact of the dispersion-induced power fading on the fiber transmission performance of OFDM-UWB radio signals

Abstract

The performance degradation of orthogonal frequency division multiplexing ultra-wide band (UWB) radio signals transmission over standard single-mode fiber is analyzed through numerical simulation. A significant performance variation along the standardized UWB band due to the fiber dispersion-induced power fading is shown. As a consequence, a periodic dependence of the optical signal-to-noise ratio degradation on the fiber length and on the RF carrier frequency is observed. IntroductionUltra-wide band (UWB) radio communication systems have been receiving a special attention over the last years. Such systems can benefit from several UWB advantages as high data rate over short distances or low data rate over larger distances broadcasting, tolerance to multi-path fading, possibility of co-existence with other employed technologies (IEEE 802.11 and IEEE 802.16) and low power consumption allowing small size/low cost integration [1] [2]. Furthermore, UWB systems can be used over different networks. High data rate over short distances UWB broadcasting is indicated for wireless personal area networks (WPAN) while low data rate is used for sensor, positioning and identification networks [1]. Previous works proposed the distribution of UWB signals to WPAN through fiber-to-thehome (FTTH) infrastructures [3] [4]. With this proposal, the end-users can benefit from the high mobility and high bit-rate over short ranges capabilities provided by the UWB-based wireless networks, whereas the main constraint associated with the delivery of such high data rates to the wireless networks is overcome due to the distribution of UWB signals over optical fiber. The transmission of orthogonal frequency division multiplexing (OFDM) and impulse radio UWB signals over different fiber paths was experimentally demonstrated in [3] and [4], achieving 1.56 Gbit/s over 100 km of standard single-mode fiber (SSMF) with bit error ratio (BER) lower than 10 -9 , for the OFDM flavour. The considered fiber paths correspond to standard lengths used in passive optical networks to interconnect distribution hubs (DH) that can be far away (up to 100 km) and to connect DH to UWB end users (up to ~60 km) [5]. However, significant performance degradation with the increase of the fiber length has been shown and the clarification of the physical effect causing such degradation still remains. In this work, the fiber dispersion-induced degradation of OFDM-UWB signals distribution over SSMF is analyzed through numerical simulation. The performance degradation is evaluated along the standardized UWB band for different SSMF lengths.