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We present a wireless link budget analysis for impulse-radio ultrawideband (IR-UWB) systems with different pulse-shaping techniques using a realistic path loss model. Simulation results confirm that a proper pulse design technique is crucial for satisfying Federal Communications Commission mask requirements and performance enhancement of IR-UWB systems. We present a novel pulse design technique, based on a linear combination of modified doublets pulses and compare it with conventional pulses such as monocycle, doublet and fifth-order derivative of Gaussian pulses. The proposed pulse outperforms the conventional pulses in terms of spectral power efficiency and achievable reach using an M-ary pulse-amplitude modulation format and a fixed data rate. Furthermore, we propose and experimentally demonstrate routing over a hybrid wired-wireless network of IR-UWB services using the proposed pulse shape. The routing functionality is realized using a single semiconductor optical amplifier based on the cross-gain modulation technique. Error-free transmission of both 1.25 Gb/s baseband wired services and 2 Gb/s wireless IR-UWB services has been achieved over 1 km fiber link. The proposed technique can efficiently distribute and multicast both wireless IR-UWB and wired services in future in-building networks. [ABSTRACT FROM PUBLISHER]

The performance of an UMTS radio over fiber link based on directly modulated lasers has been experimentally evaluated in terms of the error vector magnitude (EVM). Operational range for standard EVM values (<12%) was achieved in terms of distance and power. Also, the effect of a semiconductor optical amplifier on these signals in mono and multiwavelength was observed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 6–9, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23975 [ABSTRACT FROM AUTHOR]

An optically tunable frequency-doubling optoelectronic oscillator (FD-OEO) based on stimulated Brillouin scattering (SBS) and carrier phase-shifted double sideband (CPS-DSB) modulation is proposed and demonstrated. SBS effect provides narrowband filtering for the OEO to generate an oscillation signal with frequency equal to the Brillouin frequency shift, while a CPS-DSB modulation by using a dual-parallel Mach-Zehnder modulator is implemented to double the oscillation frequency. Owing to the wavelength-dependent Brillouin frequency shift, frequency tunability is realized by tuning the wavelength of the laser source. In the experiments, frequency-doubling microwave signals from 18.38 to 18.74 GHz are generated when the wavelength of the laser source is tuned from 1565 to 1535 nm. [ABSTRACT FROM PUBLISHER]

This letter describes a 30-Gb/s bidirectional transparent optical transmission, over a 4.4-km multimode fiber (MMF) in combination with an indoor optical wireless (OW) link, which could provide limited mobility. Due to MMF's advantages, such as lower installation costs and easy maintenance, it is used as the access link. To enhance the MMFs bandwidth and provide the feasibility to use standard single-mode devices in the OW terminal (OWT), center launching and center detection techniques are both utilized. The stability of the indoor OW channel and the modal noise in MMF are investigated. Discrete multitone modulation with power and bit loading algorithms are applied to improve system's frequency utilization efficiency and robustness. [ABSTRACT FROM PUBLISHER]

In this letter, we present a dynamic distributed antenna system based on a reconfigurable optical access network. Radio signals from the central office are delivered to the remote antenna units by means of optical channels where dynamic radio sub-carrier assignment to the antenna units is performed by reconfiguring optical channels. The bidirectional transmission experiment demonstrates that a switching time of 450 ns can be used to allocate an additional radio channel to antenna units. The impact to existing radio signals is negligible. The error vector magnitude penalty is only 0.5% and 1% for the downlink and uplink radio signals, respectively. [ABSTRACT FROM PUBLISHER]