Ultra-wideband Communication Systems Research Articles

LOCATING THE BURIED OBJECT IN THE NON-DESTRUCTIVE STRUCTURES USING TH-BPSK UWB SYSTEM

The ultra-wideband (UWB) communication system utilizing impulse signals is an attractive technique which can achieve low power consumption, high data rate, and high accuracy in location estimation. One of the applications of UWB is ground penetrating radar (GPR) which has been using to investigate non-destructive structures. In this paper, we proposed a method of locating a buried object in non-destructive structures (concrete, dry soil) using time hopping BPSK UWB (TH-BPSK UWB) modulation system with a certain pulse shape combined with Gauss-Newton nonlinear estimation algorithm. The results of the proposed method were evaluated using computer simulation in terms of the errors of estimated position and spatial resolution.

A Model-Based Systems Engineering Approach to Trade Space Exploration of Implanted Wireless Biotelemetry Communication Systems

This paper summarizes the application of model-based systems engineering (MBSE) to the development of a system trade study and decision-making tool for implantable ultra-wideband (UWB) wireless biotelemetry communications systems. The systems modeling language (SysML) is used to develop graphical representations, called descriptive models, of the system architecture, parameters, and interdependencies along with leveraging various analytical tools to produce performance and safety assessments of various system configurations. Both descriptive and analytical models are linked together to enable system designers the ability to rapidly run a wide range of system configurations such that the results can be visualized, analyzed, and pruned to meet system safety and performance requirements. This integrated system approach is more effective than typical standalone or disparate analysis since it enables system designers the ability to consider multivariate scenarios in the system simulation as compared to only a few. The modeling framework is also consistent and easily verified and validated at the component, sub-system, and system levels. An ultra-wideband communication system with an implanted transmitter sub-system is the exemplary case considered in this paper.

Hexagonal Printed Monopole Antenna with Triple Stop Bands for UWB Application

Inherently UWB (Ultra Wideband) communication systems comes with interference problem with some if the existing narrowband communication systems. These bands are stopped with the help of band-stop filter in order to reduce electromagnetic interference However, the complexity and limitations are increased due to these filters, hence this solution is turned down in those applications where design complications and complexity is of concern. Introducing various slots of specific shapes and exact dimensions however, have solved this issue for the researchers around the world. This paper presents a hexagonal PMA (Printed Monopole Antenna) with triple stop bands. The antenna is used for UWB application. The antenna is stopped the WiMAX (Worldwide Interoperability for Microwave Access), WLAN (Wireless Local Area Network) and ITU (International Telecommunication Union) bands. The antenna dimensions are 30x28x16 mm3. FR4 is used between ground and radiating patch with relative permittivity of 4.4. The VSWR (Voltage Standing Wave Ratio) is less than 2 between 3-11 GHz except WiMAX (3.1-3.7 GHz), WLAN (5.1-5.8 GHz) and the ITU frequency band (7.95-8.4 GHz). The antenna is design in CST software.

Adaptive Sub-Nyquist Spectrum Sensing for Ultra-Wideband Communication Systems

With the ever-increasing demand for high-speed wireless data transmission, ultra-wideband spectrum sensing is critical to support the cognitive communication over an ultra-wide frequency band for ultra-wideband communication systems. However, it is challenging for the analog-to-digital converter design to fulfill the Nyquist rate for an ultra-wideband frequency band. Therefore, we explore the spectrum sensing mechanism based on the sub-Nyquist sampling and conduct extensive experiments to investigate the influence of sampling rate, bandwidth resolution and the signal-to-noise ratio on the accuracy of sub-Nyquist spectrum sensing. Afterward, an adaptive policy is proposed to determine the optimal sampling rate, and bandwidth resolution when the spectrum occupation or the strength of the existing signals is changed. The performance of the policy is verified by simulations.

A VARIABLE IMPULSE WIDTH METHOD FOR IMPROVING THE RANGING ACCURACY OF IR-UWB PENETRATING SYSTEMS

Ultra Wideband (UWB) communication system utilizing impulse signals is interested recently. In the impulse radio based UWB system (IR-UWB), lots of different shaped pulses have been considered to evaluate and improve the accuracy in positioning technique. The choice of the pulse shape and pulse width strongly affects the choice of receiver bandwidth, the performance and positioning accuracy of system. In this paper, we propose an analytical method to select the pulse parameters that match the positioning distance to improve the accuracy of the system. Computer simulation results show that the proposed system gives higher accuracy than conventional narrow band (NB) system with the average error of the proposed system is 0.05 m while in the NB system is 0.35 m.

Performance of multi-band OFDM UWB communication systems in presence of IEEE802.11n WLAN interference for different antenna scheme configurations

Multi-band orthogonal frequency division multiplexing ultra-wideband (MB OFDM UWB) communication system has been a leading proposal in the IEEE 802.15.3a standard and has been adopted in the ECMA standard for wireless personal area networks. In this paper, the performance of the MB-OFDM UWB communication system in the Saleh-Valenzuela multi-path UWB channel model using different antenna scheme configurations has been analytically evaluated. The analytical evaluation has been investigated for the three antenna scheme configurations which are the single input multiple output (SIMO), the multiple input single output (MISO), and the multiple input multiple output (MIMO). The issue of existence of high power inband interference signal such as the IEEE802.11n has been also analytically evaluated. A practical link budget analysis is considered. It was shown that the performance of the desired MB-OFDM UWB SIMO/MISO/MIMO communication system can severely deteriorated due to presence of such high power inband interference signal. The obtained analytical results are validated with the aid of extensive simulation results.

Antennas for Ultra-Wideband Applications: Design and Performance Study Using Printed and Dielectric Resonators

Ultra-wideband (UWB) communication systems may make use of a miniature dielectric resonator antenna. A 50 ohm microstrip line is included into the modified T-shaped feed network to produce strong coupling and some bandwidth augmentation; the antenna element itself is a rectangular low permittivity ceramic block with a dielectric constant of 9.4. Simulations and measurements of the antenna's performance in a range of 3100–5500 MHz reveal an impedance bandwidth of 55.8% and a Voltage Standing Wave Ratio (VSWR) of 2, making it well-suited for ultra-wideband (UWB) uses.

Dual Notched Band Quad-Element MIMO Antenna With Multitone Interference Suppression for IR-UWB Wireless Applications

Ultrawideband (UWB) signals are extremely power limited due to the severe power spectral density constraints obligated by the Federal Communications Committee. Therefore, the design of radiation efficient antennas for UWB signaling is a challenging step in the design and development of impulse radio UWB (IR-UWB) communication systems, especially when these signals coexist with previously standardized narrowband (NB) wireless services. In this paper, a dual-band-notched quad-element UWB multiple-input multiple-output (MIMO) antenna design is presented. The proposed design is capable of suppressing NB interference (NBI). The NBI suppression capability of the proposed design is tested both experimentally and through simulations. Moreover, the experimentally measured spectral characteristics of the proposed design are employed in simulating the bit error rate (BER) performance of IR-UWB systems, considering the biphase modulation (BPM) scheme. Both experimental and simulation results show that the proposed design is capable of improving the BER performance of BPM-modulated IR-UWB systems in an NBI environment by suppressing the NBI signals located at six different frequencies within the bandwidth of the two band notches of the proposed design, while introducing a negligible distortion to the IR-UWB signaling waveforms.

Chaos-Based transmitted-reference ultra-wideband communications

ABSTRACTTransmitted-reference (TR) ultra-wideband (UWB) communication systems have gained increasing popularity for the usage in the low data rate application, due to its non-coherent receiver structure. In conventional TR system, non-coherency at the receiver is achieved by sending reference pulses prior to the data-bearing pulses. Then, at the receiver side, reference pulses are used as template signals for correlation with data-bearing pulses. Therefore, the orthogonality between reference and data pulses is obtained in time division multiple access (TDMA) fashion. However, the implementation of a wideband delay line is very difficult in the current low power integrated circuits. In this paper, a TR method called Chaos-Based TR (CB-TR) is proposed. In the proposed method, chaotic sequences are used to separate the reference and data pulses. Such approach exploits the benefits of chaotic signals, such as non-periodicity, easy-to-generate, impulse-like autocorrelation value and low cross-correlation value. Furthermore, in order to decrease the influence of some negative properties of conventional chaotic maps, a modified chaotic generator (MCS) is proposed. Simulation results over the IEEE 802.15.4a channel model show comparable bit error rate performance to other TR methods.

PAPR reduction in ECMA‐368 UWB communication systems using parametric discrete sliding norm transform

SummaryECMA‐368 Standard adopts multiband orthogonal frequency division multiplexing (MB‐OFDM) for high rate ultra‐wideband (UWB) communication systems as a possible candidate for indoor wireless personnel area networks. One of the main drawbacks of MB‐OFDM modulation is the high peak‐to‐average power ratio (PAPR), which limits the power efficiency of the digital‐to‐analog converter and the high power amplifier due to nonlinear distortion. In this paper, a post inverse discrete Fourier transform nonlinear transformation called parametric discrete sliding norm transform (PDSNT) is proposed to reduce the PAPR in MB‐OFDM systems. The PDSNT method in addition to its much lower computational complexity than other schemes recently proposed for ECMA‐368 UWB systems introduces an efficient controlling parameter to obtain a good tradeoff between PAPR reduction and bit error rate (BER) performance degradation. Simulation results show that the proposed PDSNT‐based MB‐OFDM scheme can achieve better performance in PAPR reduction than conventional solutions with affordable BER performance degradation in UWB channel models.

Approach for improving inter‐element isolation of orthogonally polarised MIMO slot antenna over ultra‐wide bandwidth

With the increasingly multiple-input multiple-output (MIMO) applications in ultra-wideband (UWB) communication systems, antenna researchers face big challenges in designing compact operational geometries that meet the essential demand of achieving high isolation among antenna elements over the ultra-wide operating bandwidth. Disposed antenna elements orthogonally are seen to be the most common methodology to reduce mutual coupling of MIMO antenna by exploiting polarisation diversity performance. In such configuration, the mutual coupling mainly depends on the inter-element spacing, which it may not be in line with the compact structure. In this Letter, taking the advantages of symmetry of planar UWB antennas, asymmetric feeding scheme miniaturising technique is utilised to improve the inter-element isolation of a reference MIMO antenna made up of four previously designed slot antenna elements, closely-disposed orthogonally. Analytical results have validated the design concept and the improved MIMO antenna using the halved-chopped elements, showing good performance in terms of impedance matching, isolation, radiation features, signal correlation, and system fidelity factor.

In brief

PAGE 995 The use of long coherent integration times in CZT-based algorithms could have applications for GPS systems operating in weak signal environments. A down-sampling data operation introduced by researchers in China demonstrates that the same signal acquisition can be achieved with a lower carrier-to-noise ratio and reduced computational effort. PAGE 991 Researchers in the UK working with semiconductor-based terahertz emitters have observed that temperature dependent polarity reversal within the material is an intrinsic property. Terahertz emission from various emitters over a range of temperatures revealed the semiconductor's inversion is not influenced by metallic contact, and creates potential for these devices to compete with commercial antennas. Signal detection probability improves with extended coherent integration times. PAGE 1007 A novel design for a simpler, more flexible, high performance microstrip power-divider (PD) has been implemented and tested by researchers in China. The device is composed of two dual-mode filtering PDs lacking any additional matching network, and provides significant design utility and size reduction with applications in wireless communications systems. Spectrometer set up for temperature dependence measurement of metal emitters. PAGE 967 Researchers from China have developed a frequency calibration method for a crystal-less current-controlled ring oscillator utilising a serial data signal from another chip as a reference. This newly presented auto-correlation method outperforms similar literature designs in terms of calibration accuracy, power consumption, and circuit area. Measured and simulated performances of power-divider device channels. PAGE 969 A purely digital approach to ultra-narrow pulse control for use in the picosecond and gigahertz domains has been presented by researchers in China. The digital synthesis method converts pulse-width control to the relative delay control between two signals, and can be applied to ultra-wideband communication systems and pulse radar. Frequency histograms before and after chip signal calibration. Diagram of ideal and real sharpener edge signal outputs.

Wideband Ge-Rich SiGe Polarization-Insensitive Waveguides for Mid-Infrared Free-Space Communications

The recent development of quantum cascade lasers, with room-temperature emission in the mid-infrared range, opened new opportunities for the implementation of ultra-wideband communication systems. Specifically, the mid-infrared atmospheric transparency windows, comprising wavelengths between 3–5 µm and 8–14 µm, have great potential for free-space communications, as they provide a wide unregulated spectrum with low Mie and Rayleigh scattering and reduced background noise. Despite the great efforts devoted to the development of mid-infrared sources and detectors, little attention is dedicated to the management of polarization for signal processing. In this work, we used Ge-rich SiGe alloys to build a wideband and polarization-insensitive mid-infrared photonic platform. We showed that the gradual index change in the SiGe alloys enabled the design of waveguides with remarkably low birefringence, below 2 × 10−4, over ultra-wide wavelength ranges within both atmospheric transparency windows, near wavelengths of 3.5 µm and 9 µm. We also report on the design of a polarization-independent multimode interference device achieving efficient power splitting in an unprecedented 4.5-µm bandwidth at around 10-µm wavelength. The ultra-wideband polarization-insensitive building blocks presented here pave the way for the development of high-performance on-chip photonic circuits for next-generation mid-infrared free-space communication systems.

UWB Bandpass Filter with Dual Notched Bands Using T-Shaped Resonator and L-Shaped Defected Microstrip Structure.

In this paper, an ultra-wideband (UWB) bandpass filter (BPF) with dual notched bands using a T-shaped resonator and L-shaped defected microstrip structure (DMS) is proposed and fabricated. First, the principle of generating notched bands by using a T-shaped resonator and L-shaped defected microstrip structure to determine the size parameters of the structure is analyzed. High frequency structure simulator (HFSS) software is used to analyze the performance of the filter, and advanced design system (ADS) is used to extract the equivalent circuit model parameters. The two simulation results are consistent, which further verifies the correctness of the circuit model. Finally, the filter is fabricated and measured. The measured results are in good agreement with simulated results, demonstrating good insertion loss and return loss. The proposed filter has dual independently controllable notched bands which are implemented by coupling the T-shaped resonator to the transmission line and by etching the L-shaped defected microstrip structure respectively. The proposed filter can suppress dispensable bands at 3.5 GHz and 7.5 GHz in WiMAX band and X-band to improve the performance of the ultra-wideband communication system. By adjusting the parameters of the T-shaped resonator and L-shaped defected microstrip structure, the UWB bandpass filter with dual notched bands working at WiMAX band and X-band can be designed and applied to the wireless communication system.

A Fine-Grained Analysis of Time Reversal MU-MISO Systems Over Correlated Multipath Channels With Imperfect CSI

Time reversal (TR) is regarded as a potential future transmission scheme for multi-user (MU) multiple-input single-output (MISO) ultra-wideband (UWB) communication systems. In spite of TR’s good performance in MU-MISO UWB systems, it suffers from performance degradation due to spatial correlation and imperfect channel-state information. In this paper, a comprehensive performance analysis of MU-MISO UWB systems with a TR pre-filter is provided. Both spatial correlation and channel estimation errors (CEE) are taken into account in the propagation channel model, and the system performance is mainly studied in terms of its effective signal-to-interference-plus-noise ratio (SINR), channel capacity, and bit error rate. The novel closed-form expressions for the average effective SINR are derived in order to characterize the influence of propagation conditions such as channel impulse response duration, spatial correlation, and CEE on TR performance metrics. The expressions reveal more precisely to us that spatial correlation and CEE have different effects on the average power of the desired signal, inter-symbol interference, and inter-user interference. Moreover, the impacts of spatial correlation and CEE on the performance of MU-MISO TR system are thoroughly investigated. In particular, the capacity loss of MU-MISO TR system due to spatial correlation and CEE is quantified and fully discussed at the end of this paper. It is shown that high spatial correlation and CEE cause a remarkable reduction in bandwidth efficiency. Finally, all theoretical results are confirmed by numerical simulations.

Multi-hope relay based high capacity energy efficient model for ultra wideband communication system

Demanding large bandwidth and signal robustness over a short distance, ultra wideband communication systems plays an important role. UWB systems exhibits very low spectral density, implies that the interference to narrowband systems is very small. The relay based communication has the advantages of coverage extension, range extension, increase data rates and green communication. The relay based communication with UWB frequency is used to increase the coverage area by using of relays and increasing the data rates by increasing SNR of the links using multi-hop communication. In this paper, capacity and bit error rate of relay based UWB system for indoor and outdoor channel models are analyzed. key Terms—UWB, green communication, multi-hop, capacity, bit error rate, spectral density.

Design of Fractal Array Bionic Ultra Wideband Antenna

According to the requirements of the second generation, the third generation, the fourth generation and the fifth generation mobile communication system, radio frequency identification system and ultra wideband communication system to the antenna's performance, the present paper originally combines bat wing bionic antenna and cross fractal array, designed a fractal array bionic ultra wideband antenna, fabricated the antenna sample and tested the radiation characteristics of the antenna. The result of test indicate that the antenna's working frequency range is 0.728-12.739 GHz, the antenna's working bandwidth is 12.011 GHz, the bandwidth octave is 17.49, the antenna return loss is less than -10 dB in the whole operating frequency band, the minimum value of return loss is -23.18 dB. This antenna completely covered the second generation mobile communication standard GSM frequency band, the third generation mobile communication standard TD-SCDMA frequency band, the third generation mobile communication standard WCDMA frequency band, the fourth generation mobile communication standard TD-LTE frequency band, the three candidate frequency bands of the fifth generation mobile communication, the three common frequency bands of the radio frequency identification system , and working band of ultra wideband communication system. This antenna can meet the requirements of small size, low thickness, low return loss and wide working bandwidth at the same time, it has a broad application prospect.

A highly sustainable multi-band orthogonal wavelet code division multiplexing UWB communication system for underground mine channel

The underground mine channel is highly hostile for communication. A sustainable communication system is required to be integrated as a multipurpose system capable of transferring all types of information such as data, voice and video on identical infrastructure. With its large bandwidth, the Ultra Wide Band (UWB) provides a promising solution to satisfy these requirements. The Multi-Band Orthogonal Frequency Division Multiplexing (MBOFDM) UWB system provides high resilience to Inter-Symbol Interference (ISI) caused by multipath fading channels. This study compares the performance of various existing multi-band UWB systems in the IEEE UWB channel and underground mine channel: MBOFDM, Multi-Band Orthogonal Frequency Code Division Multiplexing (MBOFCDM) and Multi-Band Orthogonal Wavelet Division Multiplexing (MBOWDM). Further, the application of 2D spreading to the MBOWDM UWB system is attempted, and as a result, the Multi-Band Orthogonal Wavelet Code Division Multiplexing (MBOWCDM) UWB system is proposed. The performance of the MBOWCDM system in the IEEE UWB channel and underground mine channel is investigated. The performance of the MBOWCDM UWB system is observed to be superior to those of other multi-band UWB systems. Moreover, the MBOWCDM UWB system supports a higher data rate with low complexity and lower overheads.

Fast Startup of LC VCOs Using Circuit Asymmetries

An LC VCO whose design includes deliberate circuit mismatches is presented. It is shown that such mismatches can reduce the oscillation start-up time due to a common-mode disturbance simultaneous with the turn-on of the tail current. The use of this technique is applied to a low-power transmitter for an ultra-wideband wireless communication system using the on–off keying modulation scheme. Measurements using a 0.18- ${\mu }\text{m}$ CMOS technology with a 4.2-GHz carrier frequency demonstrate the technique.

A novel dual‐band tunable band‐notched antenna

AbstractThis letter presents a novel dual‐band tunable band‐notched antenna. The antenna consists of a monopole ultrawideband (UWB) antenna and two kinds of novel notched structures. A tunable notched wave is obtained by adjusting the capacitance on the notched structure. Monopole antenna works well on 3.1‐10.6 GHz. The low frequency notched wave can be adjusted on the 3–4 GHz, and the high frequency band notched wave can be adjusted on the 5–6 GHz, which can avoid the influence of the WiMax and WLAN narrowband communication system on the UWB communication system, and improve the performance of the antenna system. At the same time, through the analysis of the surface current distribution of the notched antenna, the principle of the notched wave is studied. At last, a prototype of the band‐notched antenna is fabricated and measured whose simulation is consistent with the measurement.