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The use of Schottky diodes as high-speed variable impedance loads in six-port modulators are proposed and analyzed in this paper. The impedance dependency of diode parameters and local oscillator power are investigated by theoretical analysis and simulations. A prototype for a direct carrier six-port modulator using Schottky diodes for impedance generation is designed and fabricated for a center frequency...
This paper proposes a method for mitigation of non-line-of-sight (NLOS) situations in a real time location system (RTLS) using an impulse radio ultra wide band (IR-UWB). Based on our experiment, we found that there is a slight chance to meet the line-of-sight (LOS) at all the readers of RTLS in a realistic scenario. In the NLOS environment, there are two problems of packet-miss error and multi-path...
In this paper some new experimental results about the statistical characterization of the non-line-of-sight (NLOS) bias affecting time-of-arrival (TOA) estimation in ultrawideband (UWB) wireless localization systems are illustrated. Then, these results are exploited to assess the performance of various maximum-likelihood (ML) based algorithms for joint TOA localization and NLOS bias mitigation. Our...
A novel super compact microwave ultra-wideband (UWB) bandpass passive filter (BPF) is proposed using S-shape broadside-coupled striplines. A theoretical model is presented to analyze the scattering and coupling mechanism of the suggested filter. To eliminate interference, a tunable integrated notched-band filter is also introduced using a new technique. A group delay of 0.08 ns within the passband...
In this paper we jointly address the problems of node location tracking and indoor mapping in the absence of infrastructure, relying on peer-to-peer IEEE 802.15.4a Impulse Radio - Ultra Wideband (IR-UWB) links. Coarse Time of Arrival (ToA) measurements, which are obtained within a low complexity Energy Detection (ED) receiver, are mapped into the direct path and single-bounce reflected multipath components...
We present a detailed analysis of an indoor UWB channel measurement campaign. The focus is on the modeling of the deterministic part of the multipath channel using a-priori known relevant reflections and scatterers, found from an available floor plan. Our approach uses virtual signal sources, whose locations and visibilities can be calculated using simple ray-launching techniques. The channel analysis...
The design of efficient wideband diversity systems and their accurate performance evaluation depends on a complete understanding of the number of multipath components, referred to as the multipath order, available in the communication channel. This paper characterizes the multipath order based on captured channel realizations from a comprehensive indoor measurement campaign performed on the MIT campus...
UWB has been on the scene for about two decades. Results of extensive tests and measurements, and experience acquired from the design and operation of commercial products, all concurred to depict UWB as a very promising technology in many context and applications, thanks to its intrinsic characteristics. Now, wireless communications are colonizing higher frequencies and the UWB paradigm is a valid...
The bit-error rate of a 60 GHz wireless impulse radio link is investigated at a bit-rate of 4 Gbps using on-off keying. The measurement results show that it is possible to have a BER below 10−12, and the measured BER vs. Eb/No is approximately 1 dB from the theoretical value. The reliability of the wideband 60 GHz wavelet generator is furthermore confirmed by studying the number of faulty wavelets...
Jamming is a major threat against wireless communications. In this paper, we evaluate the effect of jamming on an UWB link employing a PPM non-coherent receiver. We optimize the jammer parameters that are the central frequency and the bandwidth based on the metric of the signal-to-jamming ratio. The optimization depends on different system parameters such as the channel model and the integration time...
In this work we present a low-complexity, ultra-wideband (UWB) pulse generator which complies with the Sub-GHz band in FCC regulation. This pulse generator uses a simple common emitter amplifier followed by RC high-pass filter as a differentiator to generate the monocycle pulse directly. The circuit provides a monocycle pulse when activated by a ramp edge of an external trigger signal provided by...
This paper focuses on the design of Radio-over-fibre (ROF) links for ultrawideband (UWB) applications. Due to strict regulations, network architecture and technical feasibility, UWB ROF links must have 0 dB gain, low noise figure and low DC power dissipation. Due to the low power of UWB signals, pre-amplification is possible. Design rules for UWB ROF links with a pre-amplifier are presented. If followed,...
This paper presents a combined binary pulse position modulation (BPPM)/code-multiplexed transmitted-reference (CM-TR) ultra wideband (UWB) system. The low complexity CM-TR UWB is not energy efficient as one half of the energy is used to transmit reference pulses and, even at low-to-medium data rates, it suffers from strong multi-user interference (MUI) and inter-frame interference (IFI). Keeping the...
In this paper, the EUWB approach to open technology platforms for Ultra-Wideband (UWB) communications is sketched. Both, Low Data Rate (LDR) and High Data Rate (HDR) UWB solutions are considered. Also, a potential combination of both platforms is taken into account. The LDR platform is based on the outcomes of the FP6 Project PULSRES II. The HDR platform is compliant with the ECMA 368/369 standard,...
This work presents the advantages and capabilities of the UWB beamforming RF architecture introduced in [1]. The proposed system gathers the functionalities of high ranging accuracy and angle of arrival (AOA) techniques. In addition, the system has been designed to dissipate low power. This performance is achieved thanks to a double quadrature receiver. Ranging simulation shows a 1.1cm standard deviation...
Due to the huge bandwidth, ultra-wideband (UWB) signals can provide much higher localization and ranging accuracy in comparison to traditional narrowband signals. In order to exploit this capability, various UWB based localization and ranging techniques have been proposed and investigated in recent years. In this paper, these techniques are briefly introduced and compared to provide an overview of...
We consider the deployment of impulsive ultra wide band (I-UWB) modulation for power line communications (PLC) on medium voltage (MV) networks. We firstly describe several receiver structures, and practical channel detection algorithms based on a data-aided approach. The joint estimation of the channel response and the noise correlation is also considered. Then, we address the system performance on...
The Detect and Avoid (DAA) mechanism is a widely used technique in cognitive radios to support the coexistence of primary and secondary users operating in the same spectrum portion. In this paper we describe our experience in detecting WiMAX signal (operating as a primary user) in the 3.5 GHz range using the Ultra Wide-Band (UWB) test dongles from Wisair (operating as a possible secondary user of...
Beamforming is one of the key technique for 60GHz wireless system to work at this millimeter-wave region with high propagation path loss. In IEEE 802.15.3c standard, a codebook based analog beamforming mechanism is adopted for its simplicity and feasibility. However, this simple beam sweep mechanism may not work properly in the presence of Co-Channel Interference (CCI) when dense spatial reuse is...
A simple 3D surface estimation algorithm for ultra-wideband (UWB) pulse radars is presented. This algorithm based on trilateration is easy to implement and needs no preprocessing of measurement data. Mathematical derivations of the formulas for both monostatic and bistatic radar imaging setups are derived. The performance of the proposed algorithm is verified in 3D surface measurements, and a good...
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