The aim of this document it to present an overview of some recent research activities on ultra–wideband (UWB) channel modeling. Compared to models introduced in DRB1.2, recent research was focused on more sophisticated tools to model UWB channels, like information theoretic arguments. Physical modeling of UWB channels was also investigated. Reference D.xx.xx Issue n.m 4 November 2006 507325 NEW...

-In ultra-wideband (UWB) impulse radio (IR) technology, it is important that the pulse shape be adjusted such that the power spectral characteristics not only satisfy the standard limits, but also be characterized by deep nulls at the locations of existing narrowband primary users. Cognitive Radio Technology (CR) is presented as a viable solution for UWB systems for narrowband interference supp...

Power control is a critical parameter for the design and evaluation of UWB-based WPAN networks due to its distributed control nature and non-fixed topology. The main issues in UWB PC are the channel gain fluctuations induced by indoor channel fluctuation and interference arising from narrowband systems. In this paper we introduce a joint PHY/MAC technique for DS-UWB power control design by expl...

In this paper, the significance of linearity for UWB front-end circuit is discussed. The effects of strong narrow band interferer on UWB signal are investigated. Wideband linearization techniques for UWB LNA are first proposed in this work. A high linearity UWB LNA is designed in TSMC 0.18μ CMOS process The simulation results show that the designed LNA exhibits very high IIP3 (6.9~13.8 dBm) whi...

In this paper, we present an ultra-wideband (UWB) pulse generator based on the step recovery diode. The principle of operation and the architecture of the developed pulse generator are explained. Furthermore, hardware implementation issues and the details on the generated UWB pulse including its peak voltage equal to 8.9 V, its full width at half maximum (fwhm) equal to 240 ps, and frequency sp...

Ultra Wide Band (UWB) technology is a developing wireless technology which promises high data rate short distance communication. In this paper, propose an advanced method for generating UWB signal for many UWB related applications. Important area of application is Wireless Local Area Network (WLAN). The basic idea of the work is to develop pulses of nanosecond range for the UWB transmission and...

The performance of DS-UWB and TH-UWB for a single-user link is compared for a data rate of 100 Mbps using the newly proposed, realistic UWB channel model from IEEE P802.15. The performance of suboptimal, fractionally spaced (FS), coherent Rake receivers with a pulse matched filter is evaluated with numerical simulations when different channel estimation algorithms, suitable for coherent detecti...

For lack of empty radio bands, ultrawideband (UWB) radio system allowing reuse of already occupied frequency bands is the only solution to accommodate new wireless data communication services. Two types of UWB carriers are considered here, the frequency-shifted Gaussian pulse and chaotic signal with FM-DCSK modulation. A generalized model of transmitted reference systems is introduced first tha...

Problem statement: The Multiband Orthogonal Frequency Division Multiplexing (MBOFDM) Based Ultra Wideband system (UWB) is highly susceptible to symbol timing error. Symbol timing estimation in MB-OFDM based UWB is difficult due to the presence of strongest path at delayed instant. Approach: Symbol timing estimation has two steps namely a coarse estimation and a fine estimation. In this study, a...

A major challenge in UWB signal processing is the requirement for very high sampling rate under Shannon-Nyquist sampling theorem which exceeds the current ADC capacity. Radar signal is essentially a delayed and scaled version of the transmitted pulse, determined by sparse parameters such as time delays and amplitudes. A system for sampling UWB radar signal at an ultralow sampling rate based on ...