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Nowadays, as the vivid visual enjoyment requiring in mobile display devices exploding everywhere, enormous bandwidth pressure lands in all high-speed digital transmission interfaces, such as HDMI, MIPI, DP, eDP etc. A low latency in pixels' time, flexible implementation for circuits, and high performance in visual quality video stream encoder and decoder (FHP-Codec) is proposed to relax the stress. The image structural features are analyzed, which directs an accurate 1D or 2D prediction reducing the redundancy utmost compared with DSC by 10~20% benefit in entropy, without obvious increments in circuit area and power consumption. According to the benchmark in Kodak image suite, FHP-Codec shows a considerable cost-performance ratio for display driver application fields. [ABSTRACT FROM AUTHOR]

This paper demonstrates why VCSEL-based transmitter systems are not able to capitalize on higher-order PAM modulation formats (such as PAM-4) to push the link data rate towards 100 Gbit/s with BER of better than 10 − 5 . First, the non-linear and biasing-dependent VCSEL behavior is analyzed in great detail to prove why state-of-the-art VCSELs with linear equalization are not able to reach these bandwidth targets. Consequently, based on an enhanced VCSEL model, a digital non-linear transmit equalizer is proposed to overcome voltage-dependent relaxation frequency shifts as well as data-dependent VCSEL bandwidth variations. The proposed digital non-linear equalizer is compared with a standard linear FFE structure using PAM-4 transmission experiments of 100 Gbit/s and beyond. This way, the proposed non-linear equalizer reveals a BER improvement of more than 30-fold compared to a linear FFE at a data rate of 80 Gbit/s. Finally, at 112 Gbit/s PAM-4 the non-linear equalizer was successfully demonstrated at a BER of 1.5 · 10 − 7 . [ABSTRACT FROM AUTHOR]

In order to break through the bandwidth limitation of digital instantaneous frequency measurement for a real-valued waveform, we developed a frequency estimator with a high dynamic range and low computation cost using multiple sub-Nyquist analog to digital converter (ADC) channels. The procedures of the proposed scheme are as follows: (a) perform zero-crossing detection on the real-valued signal and use multiple sub-Nyquist ADC channels to sample the output signal; (b) take several samples of each channel to calculate the folded frequency; (c) use the frequency residuals of each channel to reconstruct the frequency based on the Chinese remainder theorem. Finally, the algorithm robust analysis and simulation experiments are performed, demonstrating that the scheme of this paper has relatively good anti-noise ability and dynamic adaptability. [ABSTRACT FROM AUTHOR]

A conventional differential line (DL), commonly used on typical digital circuit boards for transmitting high-speed digital data, has fundamental limitations on the maximum signal bandwidth (~10 GHz), mainly due to signal skew, multiple line coupling, and EM interference. Therefore, to support super-high-speed digital data transmission, especially for beyond 5G communications, a practical high-performance transmission structure for digital signals is required. Balanced lines (BLs) can transmit the differential signals with multiple advantages of ultra-wide bandwidth, common-mode rejection, reduced crosstalk, phase recovery, and skew reduction, which enable super-high-speed transmission. In order to utilize the BLs in the DL-based digital circuit, connecting structures between a DL and BLs are required, but the DL-to-BL transition structures dominate the operating bandwidth and signal properties. Therefore, in this paper, properties, and design methods for two ultra-wideband DL-to-BL transitions, i.e., DL-to-CPS (coplanar stripline) and DL-to-PSL (parallel stripline) transitions, are presented. Both implemented DL-to-CPS and DL-to-PSL transitions provide high-quality performance up to 40 GHz or higher, significantly enhancing the frequency bandwidth for the transmission of digital signals while providing compatibility with the DL-based PCBs. The fabricated DL-to-CPS transition performs well from DC to 40 GHz with an insertion loss of less than 0.86 dB and a return loss of more than 10 dB, and the fabricated DL-to-PSL transition also provides good performance from DC to 40 GHz, with an insertion loss of less than 1.34 dB and a return loss of more than 10 dB. Therefore, the proposed DL-to-BL transitions can be applied to achieve super-high-speed digital data transmission with over 40 GHz bandwidth, which is more than four times the bandwidth of the DL, supporting over 200 Gbps of digital data transmission on PCBs for the next generation of advanced communications. [ABSTRACT FROM AUTHOR]

Parallel redundancy protocol (PRP) and high-availability redundancy protocol (HSR) are widely adopted protocols based on IEC 61850 standard to support zero recovery communication networks for time-critical and reliable interactions in power system substations. However, hiring these protocols comes with technical and economic constraints that impact the size of the substation network arrangement. Therefore, we will undertake a theoretical analysis of HSR, PRP, and their combinations to reach a maximum number of nodes in different substation communication architectures regarding IEC 61850 standard message time constraint requirements and IEC 62439-3 standard regulations. We will validate our findings through a simulation in the OPNET Modeler environment. In addition, we considered bandwidth efficiency by prohibiting the extra circulation of packets in the redundancy Box (RedBox) and QuadBox implementation as interfaces for HSR and PRP connection and HSR rings interconnection, respectively, which represent the main hindrance in utilizing the combination of these protocols. [ABSTRACT FROM AUTHOR]

A 24 GHz self-calibrated all-digital frequency-modulated continuous-wave (FMCW) synthesizer is presented in this article. A multi-bank digitally controlled oscillator (DCO) is employed to provide adequate frequency tuning range and high frequency resolution. A full background self-calibration scheme is proposed to linearize the DCO tuning curve for highly linear and fast chirp generation. An overlap compensator based on an adaptive lookup table (LUT) is utilized to eliminate the frequency overlaps between adjacent DCO tuning bands. The compensation words in the LUT are altered by least-mean-square (LMS) algorithm for robust and precise matching. A ramp tracker, which features real-time ramp tracking with zero steady-state phase error, is employed to estimate and stabilize the frequency ramp. Implemented in 40 nm bulk CMOS, the FMCW synthesizer prototype consumes 28 mW with a 0.26 mm2 core area. The maximum chirp bandwidth is 3.2 GHz, corresponding to 13.33% of the center frequency. Measurement results show that the root-mean-square (RMS) frequency error is reduced by 1/10 with self-calibration after 2 ms convergence time. The maximum chirp slope is up to 320 MHz/ $\mu \text{s}$ with 309 kHz RMS frequency error. The minimum RMS frequency error is 7.35 kHz under 5 MHz/ $\mu \text{s}$ chirp slope, corresponding to 0.0002% of the chirp bandwidth. [ABSTRACT FROM AUTHOR]

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This paper presents the design and development of planar triplexer slot antenna using substrate integrated waveguide (SIW) technology. The proposed antenna is realised using 'Y' shaped slot backed by SIW cavity. SIW cavity is excited by three separate feed lines for resonance at three different frequencies of 5.7 GHz, 6 GHz and 6.4 GHz with unidirectional radiation pattern and gain of 6.26 dBi, 5.87 dBi and 5.19 dBi, respectively. Average isolation of the three ports is better than 24 dB. All the simulations are carried out using high frequency structure simulation (HFSS) software. The proposed antenna is fabricated on RT Duroid 5880substrate and measured results show better performance. The developed antenna is small in size (0.79 λ × 0.78 λ), simple to fabricate and easy to integrate with planar technology making it suitable for C-band application. [ABSTRACT FROM AUTHOR]

In this paper, we present a distributed observer-type consensus controller design for general linear multiagent systems over directed digital networks with limited communication data rates. Considering that each agent can only exchange binary symbolic sequence with its neighbors due to bandwidth constraints, we adopt the probabilistic quantization approach in the distributed consensus controller design. Compared to the existing works, the main contribution is that we use distributed observer-type controllers to inhibit the impact of quantization noises in agent states. First, we study the observer-type protocols with total quantized communications, where the relative-state information of each agent is quantized. The quantized consensus can be achieved, and the upper bounds of steady-state errors in the mean-square sense are also characterized, which are related to the scale of networks, the control parameters, the quantization levels, and the structures of agents. Further, we extend the controller design based on total quantization to the partial quantization case where only the neighbors’ information is quantized. [ABSTRACT FROM AUTHOR]

This paper is concerned with the state estimation problem for a class of discrete-time singularly perturbed systems with distributed time-delays. During the data transmission through a network channel of limited bandwidth, for the sake of collision avoidance and energy saving, a dynamic event-triggered scheme is employed to schedule the data communication from the sensors to the designed estimator. First, for a given singular perturbation parameter (SPP), by constructing a novel Lyapunov–Krasovskii SPP-dependent functional, sufficient conditions are obtained to guarantee the exponentially mean-square ultimate boundedness of the error dynamics of the state estimation. Furthermore, in the case that the SPP does not exceed a predefined upper bound, a design algorithm is developed for the desired state estimator ensuring that the error dynamics is exponentially mean-square ultimately bounded. In this case, by solving certain matrix inequalities, the estimator gain is characterized without needing to know the exact SPP (as long as it stays below the given upper bound). Moreover, the ultimate bound of the error dynamics is estimated. Finally, simulation results are given to confirm the validity and advantages of the proposed design scheme of the state estimator. [ABSTRACT FROM AUTHOR]

We consider the main problems of metrological support for measurements of speed and bandwidth in digital packet data networks. We enumerate the methods for performing data rate measurements. We propose various ways of providing traceability of digital data rate meters such as upgrades to the existing standard GET 200-2012, development of a primary reference method for measuring speed, and the creation of a local verification procedure for measuring the transmission speed of digital information. Recommendations are given for the implementation of the selected method for ensuring traceability of meters for data transfer rate and bandwidth of communication channels. Suggested approaches can apply in metrology for digital communication systems. [ABSTRACT FROM AUTHOR]

We theoretically compare the performance of optical discrete multi-tone (DMT) and pulse amplitude modulation (PAM) using intensity modulated and direct detection. PAM is a lower cost, lower complexity solution than DMT, however, it is more vulnerable to chromatic dispersion on the C-band. We compare DMT and PAM taking into consideration the interplay of laser linewidth, fiber length, transmission rate, and channel bandwidth. We use a semi-analytical model to examine bit error rates. We study how system parameters shift the performance advantages between DMT and PAM. Our model can also be used to find the best hardware solution and frequency band for a target modulation format and bit error rate. [ABSTRACT FROM AUTHOR]

This paper aims to derive accurate outage probability expressions of a cognitive decode-and-forward (DF) relay system over the Nakagami-m fading channel. A secondary system and a primary system coexist in a spectrum sharing the environment. In order to protect the data transmission of the primary system, the transmission power of the secondary system cannot exceed the tolerable interference threshold of the primary system and its available peak power. In particular, we also consider the impact on the secondary system when the primary system turns on its transmitter. Simulation results align with our theoretical formulas very well. [ABSTRACT FROM AUTHOR]

Abstract Industry pushes towards ever faster and more accurate production of thin substrates. Contactless positioning offers advantages, especially in terms of risk of breakage and contamination. A system is considered designed for contactless positioning by floating a silicon wafer on a thin film of air. This paper focuses on the design of a control system, including actuators, sensors and control method, suitable for this purpose. Two cascaded control loops, with decoupled SISO controllers, are implemented for this moving mass controlled on a mass-spring system, which can be modelled as a fourth order system. The SISO controllers are first designed with classic loopshaping tools, which are then modified using fractional control. Two arguments based on examples in this system are given for the application of fractional control. Firstly, to increase the bandwidth of a regular mass-spring system, and secondly to control a plant which behaves fundamentally fractional, such as the moving mass in this cascaded fourth order system. By merely the application of fractionality, the bandwidths are extended by 14.6 % and 62 %, for the inner and outer loop respectively. A closed-loop positioning bandwidth of the wafer of 60 Hz is achieved, resulting in a positioning error of 104 nm (2 σ value), which is limited by sensor noise and pressure disturbances. This paper shows how the extension of classic loopshaping tools with fractional control can directly improve the performance, without adding to the complicatedness of the control system. Moreover it demonstrates a working concept of a novel type of contactless actuator. Highlights • Fractional order lead control is trade off between higher bandwidth and stability. • An accuracy of 104 nm is achieved for the concept of contactless positioning. • The application of fractional PID led to an improvement in bandwidth of 14.6 %. [ABSTRACT FROM AUTHOR]

Abstract Designing an efficient digital communication system requires trade-offs among Spectral Efficiency (SE), Energy Efficiency (EE), and system complexity. In this paper, these metrics are analyzed for an M -ary Continuous Phase Frequency Shift Keying (M -CPFSK) system based on average mutual information and normalized bandwidth of the system. The analysis is presented for arbitrary value of modulation index h (0 < h ⩽ 1), number of frequency tones M , and observation length n T s of the receiver. The efficiency metrics are evaluated for Nakagami- m and Generalized- K (GK) channels corrupted by Additive White Gaussian Noise (AWGN). The bounds on SE and EE for these channels are derived and illustrated. Results show that the efficiency metrics are negatively impacted by fading and shadowing characteristics of channel. An increase in observation length of receiver for M -CPFSK can be used to improve SE and EE of the system. It is observed that increasing the observation length of the receiver although improves the energy efficiency metric, even when channel effects are severe, it will be at the cost of increased system complexity. The effects of system parameters on efficiency metrics are examined and it is shown that while M -CPFSK offers better EE as the modulation index h approaches unity, it increases the system bandwidth. SE and EE metrics as a function of M -CPFSK system parameters are examined and discussed. [ABSTRACT FROM AUTHOR]

A novel method of realization of composite right-/left-handed leaky-wave antennas featuring through broadside-beam-scanning capability and utilizing coupled-line sections has been proposed. The unique feature of the presented concept is that it allows to adjust both the beam-scanning bandwidth and the distance between consecutive unit cells thanks to the introduction of additional identical transmission-line sections to the unit cell. The concept has been theoretically analyzed as well as experimentally verified by the simulations and measurements of the developed antenna operating with the transition frequency of 3 GHz. [ABSTRACT FROM AUTHOR]

It is a matter of fact that quality of experience (QoE) has become one of the key factors determining whether a new multimedia service will be successfully accepted by the final users. Accordingly, several QoE models have been developed with the aim of capturing the perception of the user by considering as many influencing factors as possible. However, when it comes to adopting these models in the management of the services and networks, it frequently happens that no single provider has access to all of the tools to either measure all influencing factors parameters or control over the delivered quality. In particular, it often happens to the over-the-top (OTT) and Internet service providers (ISPs), which act with complementary roles in the service delivery over the Internet. On the basis of this consideration, in this articlewe first highlight the importance of a possible OTT-ISP collaboration for a joint service management in terms of technical and economic aspects. Then we propose a general reference architecture for a possible collaboration and information exchange among them. Finally, we define three different approaches, namely joint venture, customer lifetime value based, and QoE fairness based. The first aims to maximize the revenue by providing better QoE to customers paying more. The second aims tomaximize the profit by providing betterQoE to the most profitable customers (MPCs). The third aims to maximize QoE fairness among all customers. Finally, we conduct simulations to compare the three approaches in terms of QoE provided to the users, profit generated for the providers, and QoE fairness. [ABSTRACT FROM AUTHOR]

The Xilinx RFSoC is the first product to integrate cutting-edge RF data converters with an FPGA SoC. This breakthrough integration delivers a dramatic reduction in system power and footprint, while offering increased flexibility for wide-bandwidth communications applications. The RFSoC monolithically integrates a quad-core 1.5-GHz ARM Cortex-A53 application processor, dual-core Cortex-R5 real-time processing units, 4,000 FPGA DSP resources, and up to 16 digital-RF transmit and receive paths. Each RF transmit path includes a 14-bit, 6.4-GS/s RF-DAC and a flexible digital up conversion (DUC) chain. The RF receive channels contain 12-bit, 4-gigasamples per second (GS/s) RF-ADCs and a flexible digital down conversion (DDC) chain. All RF paths include a programmable complex digital mixer with numerically controlled oscillator (NCO), digital compensation of RF paths, on-chip RF-clock generation, and a flexible wideband interface to the FPGA fabric. The device is housed in a 40x40-mm, 1,517-pin ball grid array (BGA) package and is manufactured in a 16-nm Fin field-effect transistor (FinFET) process. [ABSTRACT FROM AUTHOR]

A stepped frequency-modulated continuous-wave lidar system using a dual parallel Mach–Zehnder modulator with heterodyne detection is demonstrated. The lidar transmitter utilizes a modulation loop circuit composed of an electro-optic dual parallel Mach–Zehnder modulator and a fiber amplifier, as well as a tunable Fabry–Perot filter to generate a bandwidth-enhanced stepped frequency-modulated signal. In addition, a centroid algorithm is used in the receiver to process the signal with both high precision and high accuracy. The simulation results demonstrated that the ranging precision of the proposed lidar was 2.09 cm and the ranging accuracy was 0.16 cm. A validation experiment verified that the data obtained in the simulation had a modulation bandwidth of 4 GHz using a 200-MHz signal source. The improvements resulted in a frequency-modulated continuous-wave lidar system with high precision and accuracy by operating a modulated signal with a wider modulation bandwidth using signal sources with low bandwidth in a low-cost and compact structure. [ABSTRACT FROM AUTHOR]

Receiver in-phase/quadrature (IQ) imbalance caused by imperfect analog receiver front end can rapidly degrade system performance in Nyquist-subcarrier-modulation (Nyquist-SCM) direct detection scheme. These imbalances, including IQ skew, IQ gain and phase imbalance, become increasingly important when higher symbol rate, higher modulation order, and lower roll-off pulse shape are used. Here, an adaptive four real-valued widely linear equalizer in an inner two-by-two butterfly structure is used to compensate receiver IQ imbalance and channel linear distortion, which has the same computational complexity with the conventional complex-valued FIR filter. In addition, the effectiveness of adaptive equalizer is validated experimentally with offline processing through a 20-Gbps 16-QAM Nyquist-SCM signal over 40-km standard single mode fiber transmission. [ABSTRACT FROM AUTHOR]

We propose &#x201C.compressed training adaptive equalization” as a novel framework to reduce the quantity of training symbols in a communication packet. It is a semi-blind approach for communication systems employing time-domain/frequency-domain equalizers, and founded upon the idea of exploiting the magnitude boundedness of digital communication symbols. The corresponding algorithms are derived by combining the least-squares-cost-function measuring the training symbol reconstruction performance and the infinity-norm of the equalizer outputs as the cost for enforcing the special constellation boundedness property along the whole packet. In addition to providing a framework for developing effective adaptive equalization algorithms based on convex optimization, the proposed method establishes a direct link with compressed sensing by utilizing the duality of the \ell 1 and $\ell _\infty $ norms. This link enables the adaptation of recently emerged \ell 1 -norm-minimization-based algorithms and their analysis to the channel equalization problem. In particular, we show for noiseless/low noise scenarios, the required training length is on the order of the logarithm of the channel spread. Furthermore, we provide approximate performance analysis by invoking the recent MSE results from the sparsity-based data processing literature. Provided examples illustrate the significant training reductions by the proposed approach and demonstrate its potential for high bandwidth systems with fast mobility. [ABSTRACT FROM AUTHOR]

The paper presents the characterization of a 300-GHz transmission system for modern digital communications. The quality of the modulated signal at the output of the system (error vector magnitude, EVM) is measured using a vector signal analyzer. A method using a digital real-time oscilloscope and consecutive mathematical processing in a computer is shown for analysis of signals with bandwidths exceeding that of state-of-the-art vector signal analyzers. The uncertainty of EVM measured using the real-time oscilloscope is open to analysis. Behaviour of the 300-GHz transmission system is studied with respect to various modulation schemes and different signal symbol rates. [ABSTRACT FROM AUTHOR]

The influence of the human body in antenna systems has significant impact in the received signal strength (RSS) of wireless transmissions. Accounting for body effect is generally considered as being able to improve position estimation based on RSS measurements. In this work we perform several experiments with a wireless sensor network, using a sensor node equipped with an inertial measurement unit (IMU), in order to obtain the relative orientation between the sensor node and multiple anchor nodes. A model of the RSS attenuation induced by the body was created using experimental measurements in a controlled environment and applied to a real-time positioning system. A path loss exponent (PLE) estimation method using RSS information from neighbor anchors was also implemented and evaluated. Weighted centroid localization (WCL) algorithm was the positioning method used in this work. When the sensor node was placed on the user's body, accounting for body effect produced negligible improvements (6 %) in the best-case scenario and consistently degraded accuracy under real conditions, whether the node was placed on the user's body (in the order of 3 %), 10 cm away (from 14 to 35 %) or 20 cm away from the body (from 42 to 105 %) for results in the 70th percentile. The PLE estimation method showed improvements (in the order of 11 %) when the sensor node is further away from the body. Results demonstrate that the distance between sensor node and the body has an extremely important influence on the accuracy of the position estimate. [ABSTRACT FROM AUTHOR]

An improved low-profile printed antipodal drop-shaped dipole antenna for wide-band wireless applications is presented. The proposed radiating structure is integrated with a planar metal reflector useful to enhance antenna gain up to 5.5 dBi and the front-to-back ratio up to 21 dB. The geometry of reflector, feeding line, and dipole arms is optimized in order to achieve a broad operating bandwidth useful to meet the requirements of modern wireless communication protocols. Furthermore, the particular shape of the metal reflector and the adoption of a thin low-permittivity dielectric substrate result in a low distortion of the radiated field and a limited back radiation which makes the antenna suitable for UWB applications as well. These features, together with the low profile and the limited occupation area, make the antenna well adapted to mobile terminals as well as radio base stations. A locally conformal FDTD numerical procedure has been adopted to design and analyse the radiating structure, while a SEM technique has been employed to highlight the field perturbation caused by the antenna reflector as well as to extract the characteristics underlying the transient behaviour of the antenna. The experimental measurements performed on an antenna prototype are found to be in good agreement with the numerical computations. [ABSTRACT FROM AUTHOR]

ABSTRACT Two planar matched loads using substrate integrated waveguide (SIW) and absorbing material are presented. The magnetic-loss absorbing material is cut into horn and concave shapes and loaded into SIW sections respectively to form two SIW matched loads. Measured results of the proposed SIW matched loads show comparable agreement with their corresponding simulations. Moreover, the proposed matched loads exhibit fractional bandwidths of 46.1 and 68%, respectively with a return loss over 18.5 dB, as well as system integration capability, low complexity and low cost, which demonstrate their suitability for Ka- and Q-band applications. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1174-1178, 2017 [ABSTRACT FROM AUTHOR]

Error vector magnitude (EVM) and noise power ratio (NPR) measurements are well-known approaches to quantify the inband performance of communication systems and their respective components. In contrast to NPR, EVM is an important design specification and is widely adopted by modern communication standards such as 802.11 (WLAN). However, EVM requires full demodulation, whereas NPR excels with simplicity requiring only power measurements in different frequency bands. Consequently, NPR measurements avoid bias due to insufficient synchronization and can be readily adapted to different standards and bandwidths. We argue that NPR-inspired measurements can replace EVM in many practically relevant cases. We show how to set up the signal generation and analysis for power-ratio-based estimation of EVM in orthogonal frequency-division multiplexing systems impaired by additive noise, power amplifier nonlinearity, phase noise, and in-phase–quadrature (IQ) imbalance. Our method samples frequency-dependent inband errors via a single measurement and can either include or exclude the effect of IQ mismatch using asymmetric or symmetric stopband locations, respectively. We present measurement results using an 802.11ac PA at different backoffs, corroborating the practicability and accuracy of our method. Using the same measurement chain, the mean absolute deviation from the EVM is less than 0.35 dB. [ABSTRACT FROM AUTHOR]

This paper measures the actual bandwidth of wireless devices on ARM platforms supporting the IEEE 802.11ac standard as the data transmission protocol under the condition that there is no occlusion in the transmission path. The influences of the transmission distance, the data transmission duration, and the driving devices on the transmission terminal on the data transmission rate are investigated in several experiments. The results indicate that the maximum bandwidth can reach 251.63 Mbps when ARM platforms are used on the transmission terminal and the transmission distance and duration do not influence the data transmission rate significantly ( p -values are 0.3 and 0.07, respectively). We conclude that the actual data transmission rate of devices supporting the IEEE 802.11ac protocol may not reach the nominal level (~ 1Gbps), and the actual data transmission rate depends on the hardware configuration and other set up parameters. [ABSTRACT FROM AUTHOR]

Terahertz (THz) hot-electron bolometer mixers reach a unique combination of low noise, wide noise bandwidth, and high operation temperature when 6nm thick superconducting MgB2 films are used. We obtained a noise bandwidth of 11GHz with a minimum receiver noise temperature of 930K with a 1.63 THz Local Oscillator (LO), and a 5K operation temperature. At 15K and 20K, the noise temperature is 1100K and 1600K, respectively. From 0.69 THz to 1.63 THz, the receiver noise increases by only 12%. Device current-voltage characteristics are identical when pumped with LOs from 0.69 THz up to 2.56 THz, and match well with IVs at elevated temperatures. Therefore, the effect of the THz waves on the mixer is totally thermal, due to absorption in the π conduction band of MgB2. [ABSTRACT FROM AUTHOR]

This paper presents a transmission method for improving human body communications in terms of spectral efficiency, and the performances of bit-error-rate (BER) and frame synchronization, with a highly simplified structure. Compared to the conventional frequency selective digital transmission supporting IEEE standard 802.15.6 for wireless body area networks, the proposed scheme improves the spectral efficiency from 0.25 bps/Hz to 1 bps/Hz based on the 3-dB bandwidth of the transmit spectral mask, and the signal-to-noise-ratio (SNR) by 0.51 dB at a BER of 10-6 with an 87.5% reduction in the detection complexity of the length of the Hamming distance computation. The proposed preamble structure using its customized detection algorithm achieves perfect frame synchronization at the SNR of a BER of 10-6 by applying the proposed pre-processing to compensate for the distortions on the preamble signals due to the band-limit effects by transmit and receive filters. [ABSTRACT FROM AUTHOR]

The increasing core count in manycore systems requires a corresponding large Network-on-chip (NoC) bandwidth to support the overlying applications.However, it is not possible to provide this large bandwidth in an energy-efficient manner using electrical link technology. To overcome this issue, photonic link technology has been proposed as a replacement. This work explores the limits and opportunities for using photonic links to design the NoC architecture for a future Kilocore system. Three different NoC designs are explored: ElecNoC, an electrical concentrated two-dimensional- (2D)mesh NoC;HybNoC, an electrical concentrated 2D mesh with a photonic multi-crossbar NoC; and PhotoNoC, a photonic multi-bus NoC.We consider both private and shared cache architectures and, to leverage the large bandwidth density of photonic links, we investigate the use of prefetching and aggressive non-blocking caches. Our analysis using contemporary Big Data workloads shows that the non-blocking caches with a shared LLC can best leverage the large bandwidth of the photonic links in the Kilocore system.Moreover, compared to ElecNoC-based andHybNoC-based Kilocore systems, a PhotoNoC-based Kilocore system achieves up to 2.5× and 1.5× better performance, respectively, and can support up to 2.1× and 1.1× higher bandwidth, respectively, while dissipating comparable power in the overall system. [ABSTRACT FROM AUTHOR]

Synchronisers are a significant part of digital communication receivers since they are used to estimate the received signal timing. Among these synchronisers, non-data-aided (NDA) or blind synchronisers are even more important due to bandwidth efficiency. In this study, a different approach is investigated to derive new feedforward NDA timing estimators based on Newton algorithm. Two novel estimators with four and two samples per symbol are presented and compared with traditional timing estimators, respectively. One of the main advantages of the second proposed estimator is the ability to control the loop gain automatically. This ability improves the convergence speed and robustness of the design. Simulation results show that the presented estimators outperform the conventional estimators over a noisy channel, especially at small excess bandwidth and low signal to noise ratio. [ABSTRACT FROM AUTHOR]

This paper proposes a software-defined EPON architecture which replaces the hardware-implemented DBA module with reprogrammable DBA module. The DBA module allows pluggable bandwidth allocation algorithms among multiple ONUs adaptive to traffic profiles and network states. We also introduce a bandwidth management scheme executed at the controller to manage the customized DBA algorithms for all date queues of ONUs. Our performance investigation verifies the effectiveness of this new EPON architecture, and numerical results show that software-defined EPONs can achieve less traffic delay and provide better support to service differentiation in comparison with traditional EPONs. [ABSTRACT FROM AUTHOR]

In contrary to the common argument that the digital access divide is quickly closing and that the focus should shift to skills and usage, this article shows that access to digital communication is a moving target unlikely to ever be solved. While the number of subscriptions reaches population saturation levels, the bandwidth divide continuous to be dynamic. The article measures the nationally installed bandwidth potential of 172 countries from 1986 to 2014. The overarching finding is that the divide in terms of bandwidth does not show any clear monotonic pattern. It fluctuates up and down over the decades as the result of an intricate interplay between incessant technological progress and diffusion of technology. The bandwidth divide between high- and low income countries has first increased and only decreased below historic levels very recently during 2012–2014. In general it shows that the bandwidth divide is linked to the income divide, which is notoriously persistent. The bandwidth distribution among all countries is undergoing a new process of global concentration, during which North America and Europe is being replaced by Asia as the new global leader. In 2014 only 3 countries host 50% of the globally installed bandwidth potential (10 countries almost 75%). The U.S. lost its global leadership in 2011, being replaced by China, which contributes more than twice as much national bandwidth potential in 2014 (29% versus 13%). Despite this bad news about the continuous persistence of the digital access divide among countries, exploratory analysis from a global perspective brings the good news that many more individual people seem to enjoy more equal access to global bandwidth. All of this showcases the urgency to systematically develop indicators to track the digital divide in terms of bandwidth. [ABSTRACT FROM AUTHOR]

This paper presents a third-order digital tunable bandpass filter based on digitally tunable capacitor loaded microstrip open ring resonator. Magnetic dominated mixed coupling is utilized to make the coupling coefficient meet the requirement of stable bandwidth response. Electric source-load coupling is designed to generate a transmission zero for improving the frequency selectivity. This filter is designed, fabricated and measured. The measurement shows that the filter can be digitally tuned by 5-bits pure digital command. The fractional bandwidth is 9 ± 1%, and the tuning range is from 410MHz to 820 MHz. [ABSTRACT FROM AUTHOR]

In this paper, a simple and effective method is proposed for designing tunable diplexers with constant fractional bandwidth using dual-mode resonators. The proposed method directly connects two independently designed dual-mode bandpass filters and forms a tunable diplexer without any additional matching network at the common port, thus bringing significant design flexibility to the diplexer design process. Also, an alternative design process is proposed to characterize the coupling in the dual-mode resonator and external quality factors at the input/output, making it much easier for constant bandwidth designs. A second- and fourth-order diplexer consisting of dual-mode stepped-impedance microstrip resonators are designed and fabricated to demonstrate this method. The second-order diplexer is tuned using silicon varactor diodes, and covers 1.9–3.4 GHz with an insertion loss of 3.0–5.0 dB. Constant fractional bandwidths of \sim6% and \sim4.5% are obtained for the two frequency channels, respectively. In addition, due to the employment of the stepped-impedance dual-mode resonator, the second-order tunable diplexer occupies a compact area of 0.037\lambda0\times 0.158\lambda0, where \lambda0 is the free-space wavelength at the lowest frequency that the diplexer can be tuned. Simulations and measurements are presented with excellent agreement. Application areas are in multi-standard communication systems. [ABSTRACT FROM PUBLISHER]

We analyze the properties of a photonic crystal waveguide as a device capable of producing slow light along a wide bandwidth. The proposed structure consists of a square lattice of hollow silicon cylinders rotated 45° immersed on a colloidal suspension of magnetic nanoparticles; this arrangement produces “U-type” group index–frequency curves. The cylinder inner radius is carefully chosen to maximize the normalized delay bandwidth product (NDBP) and the concentration of the magnetic fluid is changed in order to make the device tunable in frequency. [ABSTRACT FROM AUTHOR]

A compact asymmetric coplanar strip (ACS)-fed monopole antenna with tri-band operation for LTE 2500, 2.4/5.2 GHz WLAN, 2.5 GHz WiMAX, 8 GHz ITU applications is presented in this paper. The proposed antenna design, which occupies an overall size of 14 × 26 mm including ground plane, is composed of an ACS feedline with rectangular stub, C-shaped and L-shaped branches. The C-shaped radiating element is used to generate 2.5 GHz first resonant mode, L-shaped branch is used to generate second resonant mode at 5.2 GHz and ACS with rectangular shaped stub is aimed to generate a third resonance at higher frequency bands between 7.0 and 8.8 GHz.The measured impedance bandwidths (|S| ≤ −10 dB) are about 285 MHz (2.4-2.685 GHz), 380 MHz (5.0-5.38 GHz) and 3.5 GHz (6.5-10.0 GHz) for the three operating band, respectively. The experimental result shows a reasonable good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

ABSTRACT This article proposes a novel, simple, microstrip-fed, circularly polarized, stacked, diagonal-slotted, wideband hexagonal microstrip patch antenna for Intelligent Transport System (ITS) applications. It has been found to operate in the Global Positioning Systems frequency L1 (GPS 1.575 GHz). The fabricated antenna shows an impedance bandwidth of 171 MHz which is around 11% (1.521-1.692 GHz) with 3 dB axial-ratio-bandwidth (ARBW) of 80 MHz which is around 5% (1.54-1.62 GHz) and for the entire 3 dB ARBW the gain achieved is over 6.5 dBi. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2548-2554, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT A printed microstrip line-fed fractal antenna is presented with a high fidelity factor for UWB applications. The antenna structure of electrical dimension 0.24 λ × 0.33 λ at lower frequency 3.1 GHz is made of a fractal patch, a slotted partial ground plane, and a microstrip feed, which is fabricated on FR4 material of low cost and dielectric. Measured results demonstrates that the fractal antenna achieves fractional bandwidth of 117.88% covering the frequency range from 3.1 GHz to more than 12 GHz with a maximum gain 3.54 dBi at 6.25 GHz. An acceptable analogy is observed between measured and simulation results. The high fidelity factor, sharply surface current distribution, time domain performances, acceptable gain, and nearly omnidirectional radiation characteristic have validated the appropriateness of this proposed fractal antenna for UWB and microwave imaging applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2580-2585, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT A five-port power divider with single-ended input and two differential-ended outputs is proposed. The frequency ranges from 9 to 11 GHz with a central frequency of 10 GHz. A stepped impedance line with open stubs is used between differential pairs for broadening the bandwidth and miniaturization of the divider. The divider is fabricated and the measurement results comply with the simulation. A proper performance for differential mode signal is achieved. The insertion loss is within 1.8 dB, the isolation is more than 15 dB, and the return loss is more than 11 dB. In addition, the common mode suppression is reached as well. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2669-2673, 2015 [ABSTRACT FROM AUTHOR]