Impulse Radio Ultra-wideband Receiver Research Articles

A 0.5–15 GHz reconfigurable IR-UWB receiver in 28 nm CMOS

A 0.5–15 GHz ultra-wideband (UWB) RF reconfigurable receiver in UMC 28 nm CMOS used for IR-UWB (impulse radio UWB) radar system is proposed in this paper. This receiver employs a 0.5–8 GHz path and an 8–15 GHz path to achieve the wide frequency band, and we proposed an RF channel select voltage-to-time converter (VTC) circuit. Two different low noise amplifiers (LNAs) are adopted in the two paths to obtain the high performance of noise figure (NF) and gain. The common drain stage and resistance negative feedback technology as well as the source degeneration inductive technology are introduced to achieve a high flat gain and fine input matching. The R-2R variable load network of a programable gain amplifier (PGA) gives it a nearly 24 dB dynamic range and approximately linear gain control. A 500MS/s time domain analog to digital converter (TD-ADC) with an equivalent sampling rate of 16GS/s is shared for the two paths which can realize the direct RF sampling. The input RF signal path selection is implemented by configuring the Band_sel signal. The receiver has reconfigurability of the RF front end and better power consumption and area. In the frequency of 0.5–8 GHz, the S11 is below −7.9 dB and the NF is smaller than 6 dB. In the frequency of 8–15 GHz, the S11 is below −8dB and the NF is smaller than 11 dB. The receiver dissipates 242.72mW with an area of 1.01 mm2

An OOK and Binary FSK Reconfigurable Dual-Band Noncoherent IR-UWB Receiver Supporting Ternary Signaling

This article presents a multiband low-power and low-complexity impulse radio ultrawideband (IR-UWB) noncoherent receiver. The proposed receiver can be digitally reconfigured in three different modes of operation, including two single-band modes and one concurrent dual-band mode. In the two single-band modes, the proposed envelope detection architecture is capable of receiving and demodulating an on–off keying (OOK) pulse stream at RF center frequencies of 2.8 or 4.8 GHz. In the concurrent dual-band mode, the proposed architecture is able to demodulate binary frequency-shift keying (FSK), in addition to OOK demodulation, at center frequencies of 3 and 5 GHz. The receiver is composed of a reconfigurable low-power differential low noise amplifier (LNA), a fully differential squarer (self-mixer circuit), low-pass filter (LPF), and variable gain baseband (BB) amplifiers. The receiver is fabricated in TSMC 130-nm CMOS process technology. The receiver can operate at up to 150 Mb/s with the ternary signaling that is enabled by the binary FSK modulation combined with the OOK modulation in concurrent dual-band mode. At its maximum gain, the receiver achieves a sensitivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 72 dBm at a bit error rate (BER) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-3}$</tex-math> </inline-formula> at a 100-Mb/s data rate. It consumes 11.9 and 13.2 mW from a 1.2-V supply in the single-band modes and concurrent dual-band mode, respectively.

A Low-Power Squaring Circuit with Regulated Output and Improved Settling Time in 180 nm CMOS for 3–5 GHz IR-UWB Applications

Abstract. This paper demonstrates a low-power squaring circuit for 3–5 GHz non-coherent Impulse-Radio Ultra-Wideband (IR-UWB) receivers for Pulse Position Modulation (PPM) in a low-cost 180 nm CMOS technology. The squaring, which is the key element in typical IR-UWB receivers, is performed exploiting the non-linear transfer function of a MOS transistor. For a high gain at low power consumption the transistor is biased in the moderate inversion region, where the second-order derivative of the transconductance gm and, as a result, the quadratic term in the transfer function reaches a maximum. A control loop was implemented to set the dc output voltage to a defined value and thus to allow a comparison of the squarer output signal with a defined threshold voltage, which can easily be set and adjusted (e.g. by a DAC). To speed up the settling time of the output and hence to reach higher data rates, a novel slew-rate booster is implemented at the output. Thereby, the squarer is capable of data rates of up to 15.6 Mbit s−1, which is more than two times higher compared to the circuit without the slew-rate booster, while only consuming 72.4 µW in addition. In the extracted post-layout simulations the whole circuitry consumes 724 µA at a 1.8 V power supply, resulting in a power consumption of 1.3 mW.

Time-shift immunity for wireless sensor network based on discrete wavelet packets

Wavelet-based Ultra Wide Band communications rely on receiver collecting data simultaneously from many transmitters and without interference thanks to the orthogonality between primitive wavelet packets. Nevertheless, there is a particular case for which the communication fails. Indeed, the time-shift between primitive wavelet packets results in a loss of the orthogonality of these wavelet packets. This paper proposes an asynchronous Impulse Radio-Ultra Wide Band (IR-UWB) transmission suitable in Wireless Sensor networks without any distinction between the transmitters. The originality of the proposed solution is to ensure a time-shift immunity of IR-UWB receivers by finding the unique combination of shifted primitive packets. For this purpose, finding the one zero result of successive subtractions between received and primitive packets is performed. Considering a given wavelet, the proposed solution is able to decode the shifted-mixed primitive packets from multiple transmitters whatever the time-shift between each packets.

Synchronisation free non‐coherent on–off keying demodulation techniques

Digital envelope detection, self-correlation and high frequency sampling techniques are proposed for high data rate demodulation of on-off keying signals that are widely used in impulse radio ultra-wideband receivers. The proposed designs eliminate the requirement of complex synchronisation circuit architectures and algorithms. The presented circuits are all digital and can be utilised in the baseband synchronisation. The digital envelope detection and self-correlation methods are implemented in 130 nm complementary metal oxide semiconductor (CMOS) technology and concepts are verified with measurement results. Post-layout simulation results are given for the high frequency sampling technique. Measurements show that the digital envelope detector demonstrates successful operation up to 600 Mbps data rate with 2.1 mW power consumption. The self-correlator consumes 10 mW with 100 Mbps data rate in the measurements. The post-layout simulations results show that the high frequency sampler can operate at 2 mW with 500 Mbps data rate.

Pilot-Based TI-ADC Mismatch Error Calibration for IR-UWB Receivers

In this work, we first provide an overview of the state of the art in mismatch error estimation and correction for time-interleaved analog to digital converters (TI-ADCs). Then, we present a novel pilot-based on-line adaptive timing mismatch error estimation approach for TI-ADCs in the context of an impulse radio ultra wideband (IR-UWB) receiver with correlation-based detection. We introduce the developed method and derive the expressions for both additive white Gaussian noise (AWGN) and Rayleigh multipath fading (RMPF) channels. We also derive a lower bound on the required ADC resolution to attain a certain estimation precision. Simulations show the effectiveness of the technique when combined with an adequate compensator. We analyze the estimation error behavior as a function of signal to noise ratio (SNR) and investigate the ADC performance before and after compensation. While all mismatches combined cause the effective number of bits (ENOB) to drop to 3 bits and to 6 bits when considering only timing mismatch, estimation and correction of these errors with the proposed technique can restore a close to ideal behavior. We also show the performance loss at the receiver in terms of bit error rate (BER) and how compensation is able to significantly improve performance.

Compact digital implementation of a non‐coherent IR‐UWB transmitter and receiver

Non-coherent impulse-radio ultra-wideband (IR-UWB) transceivers are attractive candidates for applications where the silicon area and power consumption are relatively limited. This study presents the compact digital architecture design and implementation of a non-coherent IR-UWB transmitter and receiver based on the energy detection scheme, including the synchroniser module. The software models of the designed transceiver are simulated and verified in both floating-point and fixed-point numerical representations. The synthesisable Verilog description of the transmitter and receiver architectures is simulated and verified against their fixed-point simulation model. The transmitter and receiver are implemented in the authors custom-developed field-programmable gate array (FPGA) board. The bit error rate performance of the transmitter and receiver is measured in real-time on the FPGA, utilising an accurate on-chip Gaussian noise generator. The characteristics and implementation results of the transmitter and receiver architecture on the FPGA are presented. An application-specific integrated circuit (ASIC) architecture of the IR-UWB transceiver is estimated to occupy 0.0227 mm 2 and dissipate 760 mW from a 1.0 V supply while operating at 82 MHz in a standard 32 nm complementary metal-oxide-semiconductor technology.

A 1.9-mm-Precision 20-GHz Direct-Sampling Receiver Using Time-Extension Method for Indoor Localization

This paper presents an impulse-radio ultra-wideband (IR-UWB) receiver design for precise wireless ranging using a newly proposed direct sampling with time-extension (DTE) method. To overcome the problems encountered in high-speed sampling for impulse signals, the DTE method, which exploits the characteristics of an impulse, is proposed. The proposed method performs high-speed sampling only during the period when short pulses exist, and quantizes the sampled signal during the dead time where no pulses exist. The high-speed impulse signal can be easily digitized using low-speed analog-to-digital converter. We designed and fabricated the IR-UWB receiver using a 65-nm CMOS process. The measurement result shows a 1.9-mm resolution for indoor wireless ranging within a 1-m range. The receiver has a power consumption of 70 mW at 1.2 V and energy efficiency of 1554 nJ/pulse.

A self-duty-cycled 7.2–8.5 GHz IR-UWB receiver for low power and low data rate applications

A self-duty-cycled non-coherent impulse radio-ultra wideband receiver targeted at low-power and low-data-rate applications is presented. The receiver is implemented in a 130 nm CMOS technology and works in the 7.2---8.5 GHz UWB band, which covers the IEEE 802.15.4a and 802.15.6 mandatories high-band channels. The receiver architecture is based on a non-coherent RF front-end (high gain LNA and pulse detector) followed by a synchronizer block (clock and data recovery or CDR function and window generation block), which enables to shut down the power-hungry LNA between pulses to strongly reduce the receiver power consumption. The main functions of the receiver, i.e. the RF front-end and the CDR block, were measured stand-alone. A maximum gain of 40 dB at 7.2 GHz is measured for the LNA. The RF front-end achieves a very low turn-on time (<1 ns) and an average sensitivity of ź92 dBm for a 10ź3 BER at a 1 Mbps data rate. A root-mean-square (RMS) jitter of 7.9 ns is measured for the CDR for a power consumption of 54 µW. Simulation results of the fully integrated self-duty-cycled 7.2---8.5 GHz IR-UWB receiver (that includes the measured main functions) confirm the expected performances. The synchronizer block consumes only 125 µW and the power consumption of the whole receiver is 1.8 mW for a 3% power duty-cycle (on-window of 30 ns).

On the Variance-Based Detection for Impulse Radio UWB Systems

A variance detection (VD)-based impulse radio ultra-wideband (IR-UWB) system has the potential of mitigating narrowband interference (NBI), even in multipath environments. However, as a highly nonlinear system, which involves fourth-order multiplications, comprehensive analysis and evaluations of its performances have not been seen so far. In this paper, we address the issues by developing a log-normal random distribution model for the VD-based IR-UWB receiver and deriving the analytical bit-error-rate formulas for the system in both additive white Gaussian noise and CM1 multipath channels with and without NBIs for the first time. Furthermore, through both theoretical analysis and simulations, we show that the presented VD-based receivers can outperform the conventional energy-detection-based and the fourth-order detection-based receivers and have a stronger inherent ability to mitigate destructive performance degradation caused by strong NBIs. This makes the VD-based IR-UWB system a good candidate as a non-coherent IR-UWB receiver for low power and low complexity applications.

A Time-Based Angle-of-Arrival Sensor Using CMOS IR-UWB Transceivers

In this paper, we present a time-based angle-of-arrival (AoA) sensor using the impulse-radio ultra-wideband (IR-UWB) technology. Arrival angles are estimated using the time difference of the received signal, which is transmitted from a target between two IR-UWB receivers. The most salient feature of this system is high precision angle estimation, which is possible with simple and compact hardware, because its operation is based on a time-based approach. The receiver in the AoA sensor consumes 50 mA at 1.2 V supply voltage and the sensitivity is -61 dBm. The measurement result shows that angle error is lower than ±1°.

Weighted Symbol Decision for Transmitted Reference Impulse Radio Ultra-Wideband Receiver by Modifying Hadamard Matrix

The UWB technique is employed in this study to exclude unusual multipath components by introducing a modified Hadamard matrix. Within the concept of this approach, IPI is totally removed and the S/N is improved. The successful UWB developments were always challenged by some external factors such as noise, interference and wrong multipath components. The challenges were treated by several researchers and, in many occasions, success was achieved in improving the data rate. The basic objectives of the improvement include removing the inter-pulse interference, distinguishing the wrong multipath components and to achieve high accuracy. Transmitted reference impulse radio ultra-wideband is only one of these techniques where it is aimed to have better detection and estimation. The analogue signals are digitalized -a crucial step that significantly pushed transmitted reference impulse radio ultra-wide to a new frontier. The basic element of this study is to digitalize the output quantities of integrable data by using analogue-to-digital convertor. The other element of this study is to modify the Hadamard matrix in transmitter and receiver to achieve total removal of inter-pulse interference. As a result, the estimation and the decision were enhanced and, on other side, a reduction in signal-to-noise ratio by amount ranges from 7.12% to about 14.42% at the receiver compared to the previous modification (modified hoped single delay). Other achievements were performed by targeting inter-pulse interference total removal and the wrong multipath error was altered which led to high accuracy, better information and less simple error rate.

Improved Noncoherent UWB Receiver for Implantable Biomedical Devices.

The purpose of this paper is to describe a novel noncoherent receiver architecture to improve the error performance of impulse-radio ultrawideband (IR-UWB) in bioimplanted devices. IR-UWB receivers based on energy detection are popular in biomedical applications owing to the low implementation cost/complexity and the high data rates that UWB can potentially support. Implanted devices suffer from severe frequency-dependent attenuation due to human blood and tissues, while most receivers in the literature are designed based on commonly used indoor wireless channel models. We propose a novel receiver design that is based on judiciously combining the energies in different bands of the signal spectrum with a weighted linear combiner. We derive the optimum coefficients of the combiner. The receiver retains almost all of the advantages of a conventional noncoherent detector, but can also compensate for attenuation properties of blood/tissue. The receiver design can be adapted to different implantation depths by simply varying the combiner weights. The receiver can also be considered to be a simple form of equalizer for noncoherent reception. Our simulations show about 2-dB improvement over other commonly used receivers. This receiver design is significant in that it can enhance critical battery life of implanted transmitters.

Impulse radio UWB receiver analysis of non‐coherently detected orthogonal signal

In this Letter, performance analysis of an impulse radio (IR) ultra wideband (UWB) correlation based receiver utilising non-coherent detection of orthogonal signalling is provided. The receiver's performance is presented through analysis and simulations in the additive white Gaussian noise (AWGN) channel. Results which show that in non-coherent detection of binary orthogonal signalling there is a difference between the traditional narrowband and IR approaches are provided. In the narrowband communication, there is a well-known, approximately 1 dB, difference between coherent and non-coherent orthogonal signal detection in AWGN. It is demonstrated here that in the binary orthogonal signalling of IR receiver the difference between coherent and non-coherent detection is insignificant, only tenths of decibels. This can be significant piece of information while considering different receiver structures for wireless sensor networks.

On Integration and Validation of a Very Low Complexity ATC UWB System for Muscle Force Transmission.

The thresholding of Surface ElectroMyoGraphic (sEMG) signals, i.e., Average Threshold Crossing (ATC) technique, reduces the amount of data to be processed enabling circuit complexity reduction and low power consumption. This paper investigates the lowest level of complexity reachable by an ATC system through measurements and in-vivo experiments with an embedded prototype for wireless force transmission, based on asynchronous Impulse-Radio Ultra Wide Band (IR-UWB). The prototype is composed by the acquisition unit, a wearable PCB 23 × 34 mm, which includes a full custom IC integrating a UWB transmitter (chip active silicon area 0.016 mm(2), 1 mW power consumption), and the receiver. The system is completely asynchronous, it acquires a differential sEMG signal, generates the ATC events and triggers a 3.3 GHz IR-UWB transmission. ATC robustness relaxes filters constraints: two passive first order filters have been implemented, bandwidth from 10 Hz up to 1 kHz. Energy needed for the single pulse generation is 30 pJ while the whole PCB consumes 5.65 mW. The pulses radiated by the acquisition unit TX are received by a short-range and low complexity threshold-based 130 nm CMOS IR-UWB receiver with an Ultra Low Power (ULP) baseband unit capable of robustly receiving generic quasi-digital pulse sequences. The acquisition unit have been tested with 10 series of in vivo isometric and isotonic contractions, while the transmission channel with over-the-air and cable measurements obtained with a couple of planar monopole antennas and an integrated 0.004 mm(2) transmitter, the same used for the acquisition unit, with realistic channel conditions. The entire system, acquisition unit and receiver, consumes 15.49 mW.

On the Nonlinear Teager-Kaiser Operator for Energy Detection Based Impulse Radio UWB Receivers

In this paper, by modeling a narrowband interference (NBI) as a wide-sense stationary (WSS), zero-mean Gaussian bandpass random process, a systematic theoretical framework is developed for the first time to characterize the operation and performance improvement of energy detection (ED) based impulse radio ultra-wideband (IR-UWB) receivers that employ a nonlinear Teager-Kaiser operator (TKO) and a highpass filter. Furthermore, through both theoretical analysis and simulations, we have identified (1) that the TKO technique can effectively mitigate not only the performance degradation caused by an NBI but also that caused by additive white Gaussian noise and (2) that a larger bandwidth of the UWB signal leads to better mitigation. Therefore, the TKO technique is considered as a very promising technique to improve the overall performance of ED-based IR-UWB receivers no matter an NBI is present or not.

Polarity-Invariant Square Law Technology for Monobit Impulse Radio Ultra Wideband Receivers

In this paper, a novel nonlinear signal processing technology, which is denoted as the polarity-invariant square law (PISL) algorithm, is proposed to compensate nonlinear distortions caused by monobit digitization and to mitigate the performance degradation of impulse radio ultra wideband (IR-UWB) receivers employing monobit analog-to-digital converters (ADCs). An analytical framework based on characteristic functions has been developed to evaluate bit error rates of monobit transmitted-reference (TR) receivers and performance improvement offered by the PISL algorithm. Both theoretical analysis and simulations show that by employing the PISL algorithm, the monobit weighted TR (MWTR) receivers can achieve a bit-error-rate performance that is more than 10 dB over the direct-reference algorithm and is less than 1.5 dB away from the performance bound of the MWTR receivers in intravehicle UWB channels. Furthermore, the MWTR receiver employing the PISL algorithm is insensitive to a correlation interval; this feature not only reduces complexity of the receiver design but also ensures performance robustness over various multipath channels. Therefore, the PISL algorithm can be considered an enabling technology for the monobit IR-UWB receivers that demand high performance, lower power consumption, and low complexity.

A CMOS Impulse Radio Ultra-Wideband Receiver for Inner/Inter-chip Wireless Interconnection

This paper presents a CMOS impulse radio ultra-wideband (IR-UWB) receiver implemented using IBM 0.13um CMOS technology for inner/inter-chip wireless interconnection. The IR-UWB receiver is based on the non-coherent architecture which removes the complexity of RF architecture (such as DLL or PLL) and reduces power consumption. The receiver consists of three blocks: a low noise amplifier (LNA) with active balun, a correlator, and a comparator. Simulation results show the die area of the IR-UWB receiver of 0.2mm2, a power gain (S21) of 12.5dB, a noise figure (NF) of 3.05dB, an input return loss (S11) of less than -16.5dB, a conversion gain of 18dB, a NFDSB of 22. The receiver exhibits a third order intercept point (IIP3) of -1.3dBm and consumes 22.9mW of power on the 1.4V power supply.

Design of a parallel low power flash A/D converter for the sub-sampling IR-UWB receiver

This paper presents the design of a dual-channel 4-bit analog-to-digital converter (ADC) for the sub-sampling impulse radio ultra-wideband receiver with the sampling rate of 2.112 GS/s. The ADC's specifications are optimized at the system level. Two parallel channels help to achieve high conversion speed and low power consumption. To tackle the problem of clock mismatch between the channels, a twice sampling front end is used. An improved averaging termination technique using intended asymmetric spatial filter response is proposed. This circuit is designed in a 0.13 μm CMOS technology with 1.2 V power supply. Simulation results show a 26 dB SNDR at 2.112 GHz sampling rate with 36 mW power consumption and the effective figure of merit value is 0.24 pJ/step.

CMOS IR-UWB Receiver for $\pm$9.7-mm Range Finding in a Multipath Environment

This brief implements an impulse radio ultrawideband receiver (Rx) for accurate wireless ranging. The ranging accuracy of ±9.7 mm is achieved in a multipath environment by employing the proposed leading edge detection method with a time-to-digital converter (TDC). The Rx extracts the leading edge of the input pulse, and the TDC measures the time of arrival, which is the time interval between the leading edge of a received signal and the reference clock synchronized with a transmitter (Tx). The Rx is implemented with 130-nm CMOS and consumes 46.8 mW.