Stephane Paquelet

An impulse radio asynchronous transceiver for high data rates

The purpose of this paper is to provide an operative way of achieving high data rates for impulse radio (IR) transmission based systems. Since applications targeted for ultra wide band (UWB) are liable to be low-cost, we especially focus on simple transceiver design. To that effect, we present an original demodulation scheme adapted to a multi-band ON-OFF keying modulation. From the receiver point of view, we impose relaxed channel estimation constraints and derive suitable signal processing schemes and simple hardware architectures. Indeed, we only consider the benefit from a limited a priori channel knowledge: approximative delay spread and energy level. The associated optimum demodulation turns out to be a non-trivial energetic threshold comparison whose precise theoretical computation admits an analytical solution proving its feasibility. Numerical results are eventually performed for IEEE 802.15.3a channel models and FCC requirements; they obviously demonstrate the potential of these techniques.

An energy adaptive demodulation for high data rates with impulse radio

The purpose of This work is to provide an operative way of achieving high data rates for impulse radio (IR) transmission based systems. Because applications targeted for ultra wide band (UWB) are low-cost, we especially focus on simple transceiver design. To that effect, we present an original demodulation scheme adapted to a multi-band on-off keying (OOK) modulation. The receivers novelty consists of considering only the benefit from approximative delay spread and energy level to relax channel estimation constraints. The optimum demodulation turns out to be a non-trivial energetic threshold comparison whose precise theoretical computation admits an original analytical solution proving its feasibility. The knowledge of the available energy as well as the noise level required to set the threshold is easily obtained by appropriate estimators. Finally, in addition to simple hardware architectures, numerical results show the efficiency of these techniques.

A 1 nJ/b 3.2-to-4.7 GHz UWB 50 Mpulses/s double quadrature receiver for communication and localization

This paper describes the integration in a 0.13 µm CMOS of an Ultra Wide Band (UWB) receiver for communication and localization. It operates in the whole 3.2-to-4.7 GHz band of the IEEE.802.15.4a regulation mask. The proposed double quadrature coherent architecture allows exploiting high resolution capability of short pulses in the time domain, with a low sampling clock at 50 MHz. Architecture offers high flexibility to cope with various channel conditions and robustness against out of band blockers. Maximum measured ranging error at 4m in wireless link is 3.8 cm and total receiver consumption at 50 Mpulses/s rate is 50 mW.

Double-Quadrature UWB Receiver for Wide-Range Localization Applications With Sub-cm Ranging Precision

The interest of industry for localization technologies is growing, because of their ability to allow a wide variety of applications. Among the different technologies, UWB is known to potentially offer the best precision. This paper presents a fully integrated low-power UWB impulse radio receiver dedicated to communication and ranging applications. The new architecture based on double quadrature is used to reach sub-cm ranging precision while limiting the speed requirements and complexity of ADC and digital signal processing. Much attention has been paid to rejecting the out-of-band signals which could degrade receiver performance while fully exploiting the available spectrum in the [3-5 GHz] band. The 5.8-mm2 0.13- μm CMOS receiver consumes 50 mW at 50-Mb/s maximum data rate. It shows -95-dBm sensitivity at 1 Mb/s and 2.5-mm maximum ranging error at 10 m.

An ultra-wide band umbilical cord for cognitive radio systems

This paper describes how cognitive radio (CR) could benefit from software-defined radio (SDR) compatible ultra-wide band (UWB) systems. It introduces the notion of umbilical cord that can keep a CR device connected to its surrounding world, thanks to sensing and low speed over-the-air reconfiguration (OTAR) means provided by low-data rate (LDR) systems, and to fast OTAR downloading facilities based on high-data rate (HDR) hot spots. A particular UWB architecture supporting SDR-compatible technological constraints is proposed as candidate to realize this promising combination of capabilities

A mathematical model for the TCP tragedy of the commons

This paper presents a novel mathematical model for the TCP Tragedy of the Commons, using Game Theory concepts. This tragedy may appear in a TCP/IP-based network when hosts do not respect the protocol rules and try to monopolize the shared network resources by using a selfish strategy. Our model quantifies the effects of this evil behavior in a simple and standard network topology and allows to obtain some interesting results which we prove formally. Finally, we validate the model results by comparing its predictions with a set of extensive simulations carried out using the NS Network Simulator.

Statistical analysis of noise in broadband and high resolution ADCs

The estimation of mismatch-induced errors between the channels of a Time-Interleaved ADC is crucial for implementing an efficient calibration method. This step is often done with the assumption that all the noise sources have a white gaussian distribution. In this paper we analyze the statistical properties of noise components in wideband ADCs in terms of Probability Density Function (PDF) and Power Spectral Density (PSD) and discuss some conditions of whiteness.

Performance of a simple architecture of an analog CMOS detector for MB-UWB receiver

This paper presents an implementation study of an analog CMOS pulse detector. The detector includes four stages: squarer, current amplification, an integrator and a sample and hold. The main objective is to realize the pulse detection function with less complexity design, low power consumption and low mass fabrication cost. Also, it must operates in the 3.1–10.6 GHz UWB band for a multi-band impulse radio receiver. The noise performance of the detector is studied. Transistors mismatches and imperfection of the current amplifier are theoretically studied in order to evaluate their effects on the global circuit performances. CADENCEs spectre simulation results in 0.35 µm CMOS technology are presented to validate this approach. Monte-Carlo simulation results are equally given in order to enforce the analytical studies. The proposed detector consumes only 2 mW with a ±1.8 V supply.

A non-coherent multi-band IR-UWB HDR transceiver based on energy detection

This paper presents an architecture of an IR-UWB MB-OOK non-coherent transceiver. Channel measurements performed for both LOS and NLOS short-range communications in real indoor environment based on this realized prototype are provided. A comparison between the use of directional and omnidirectional antennas at both emission and reception is presented. Then, an estimation of the data rate of the communicating system is given. Also, an implementation study of an analog CMOS pulse detector is presented. The main objective is to realize the pulse detection function with less complexity design, low power consumption and low mass fabrication cost. Also, it must operates in the 3.1–10.6 GHz UWB band for a multi-band impulse radio receiver. The noise performance of the detector is studied. CADENCEs spectre simulation results in 0.35 µm CMOS technology are presented to validate this approach. The proposed detector consumes only 2 mW with a ±1.8 V supply.

Performance of a low-power multi-band IR-UWB transceiver based on energy detection

This paper presents an architecture of a low power non-coherent multi-band IR-UWB transceiver. The proposed system was studied and a prototype was realized. Also, it concerns with the study of the performance and a future implementation of such a system based on energy detection. Channel measurements performed in both LOS and NLOS short-range communications in real indoor environment are provided. Finally, the performance of a communicating system based on energy detection and a data rate evaluation are given.