Bandwidth Tradeoff Research Articles

Radiation Behavior of Synthesized LiTi Ferrite Based Microstrip Antenna in X Band

The paper comprehensively explores the development, characteristics, and antenna applications of lithium titanium (LiTi) ferrite. Utilising a solid-state reaction technique, the study examines the substrate’s electrical, magnetic, and structural properties in detail. Additionally, it assesses the far-field radiation patterns of a magnetically-biased LiTi ferrite-based antenna. Key findings point to a noticeable reduction in mutual coupling and radiated power, along with an isotropic redistribution of minor side lobes. Comparative analysis with RT-duroid substrates in X band frequency spectrum highlights the LiTi ferrite-based antenna’s remarkable 62.85 % miniaturization and consistent directivity, along with a superior quality factor. These findings emphasise LiTi ferrite’s potential for compact, high-performance applications in demanding environments. LiTi ferrite’s advantages in miniaturisation and stability position it for specific applications, despite trade-offs in bandwidth, gain, and impedance compared to RT-duroid substrates.

Simulated Channel Length Variation Effects on Regulated Cascode Input Stage-Based Transimpedance Amplifier for Fiber Optics Applications

A proposed transimpedance amplifier with channel length variation is simulated. The amplifier consists of a regulated cascode input stage followed by a common gate-common source configuration. A channel length series (45 nm, 90 nm and 130 nm) in CMOS technology was introduced within the proposed amplifier in order to achieve comparative performance analysis. There are two key findings from this study. On one hand, it was found that the trade off in gain versus bandwidth and input referred noise current still applies when channel length is moved upward from 45 nm up to 130 nm. A series of transimpedance amplifier gains (42.16 dBΩ, 44.34 dBΩ and 46.25 dBΩ) that correspond to (1.80 GHz, 1.33 GHz and 1.06 GHz) of bandwidths is reported corresponding to the above channel length series respectively with an input referred noise current spectral density series (16.35 pA/sqrt(Hz), 12.17 pA/sqrt(Hz) and 10.60 pA/sqrt(Hz)) of reduction. On the other hand, a reduction in power consumption occurred as channel length is moved upward for the same proposed topology. A total power consumption series (0.611 mW, 0.287 mW and 0.173 mW) was reported that corresponds to the above channel length series.

A Low-Noise Low-Power 0.001Hz-1kHz Neural Recording System-on-Chip With Sample-Level Duty-Cycling.

Advances in brain-machine interfaces and wearable biomedical sensors for healthcare and human-computer interactions call for precision electrophysiology to resolve a variety of biopotential signals across the body that cover a wide range of frequencies, from the mHz-range electrogastrogram (EGG) to the kHz-range electroneurogram (ENG). Existing integrated wearable solutions for minimally invasive biopotential recordings are limited in detection range and accuracy due to trade-offs in bandwidth, noise, input impedance, and power consumption. This article presents a 16-channel wide-band ultra-low-noise neural recording system-on-chip (SoC) fabricated in 65nm CMOS for chronic use in mobile healthcare settings that spans a bandwidth of 0.001 Hz to 1 kHz through a featured sample-level duty-cycling (SLDC) mode. Each recording channel is implemented by a delta-sigma analog-to-digital converter (ADC) achieving 1.0 μ V rms input-referred noise over 1Hz-1kHz bandwidth with a Noise Efficiency Factor (NEF) of 2.93 in continuous operation mode. In SLDC mode, the power supply is duty-cycled while maintaining consistently low input-referred noise levels at ultra-low frequencies (1.1 μV rms over 0.001Hz-1Hz) and 435 M Ω input impedance. The functionalities of the proposed SoC are validated with two human electrophysiology applications: recording low-amplitude electroencephalogram (EEG) through electrodes fixated on the forehead to monitor brain waves, and ultra-slow-wave electrogastrogram (EGG) through electrodes fixated on the abdomen to monitor digestion.

High-efficiency dual single layer graphene modulator integrated on slot waveguides.

This paper presents an experimental and theoretical investigation of a graphene-integrated electro-absorption modulator (EAM) based on a slot waveguide. Due to the enhanced light-matter interaction of graphene, the device exhibits an impressive modulation efficiency (0.038 dBµm-1V-1) and bandwidth (≈ 16 GHz). Starting from these results, we carried out an extensive design study, focusing on three crucial design parameters and exploring the associated trade-offs in insertion loss, extinction ratio and bandwidth. The simulation results offer valuable insights into the influence of each design parameter, reaffirming that our slot waveguide platform holds great promise for realizing a high-performance EAM balancing optical and electrical performance. It is important to note that the slot waveguide was defined through standard deep ultraviolet (DUV) lithography, allowing seamless integration into high-density systems.

Collaborative 3D Object Detection for Autonomous Vehicles via Learnable Communications

3D object detection from LiDAR point cloud is a challenging task in autonomous driving systems. Collaborative perception can incorporate information from spatially diverse sensors and provide significant benefits for accurate 3D object detection from point clouds. In this work, we consider that the autonomous vehicle uses local point cloud data and combines information from neighboring infrastructures through wireless links for cooperative 3D object detection. However, information sharing among vehicles and infrastructures in predefined communication schemes may result in communication congestion and/or bring limited performance improvement. To this end, we propose a novel collaborative 3D object detection framework using an encoder-decoder network architecture and an attention-based learnable communications scheme. It consists of three components: a feature encoder network that maps point clouds into feature maps; an attention-based communication module that propagates compact and fine-grained query feature maps from the vehicle to support infrastructures, and optimizes attention weights between query and key to refine support feature maps; a region proposal network that fuses local feature maps and weighted support feature maps for 3D object detection. We evaluate the performance of the proposed framework on CARLA-3D, a new dataset that we synthesized using CARLA for 3D cooperative object detection. Experimental results and bandwidth consumption analysis show that the proposed collaborative 3D object detection framework achieves a better detection performance and communication bandwidth trade-off than five baseline 3D object detection models under different detection difficulties.

Does the syrinx, a peripheral structure, constrain effects of sex steroids on behavioral sex reversal in adult canaries?

We previously confirmed that effects of testosterone (T) on singing activity and on the volume of brain song control nuclei are sexually differentiated in adult canaries: females are limited in their ability to respond to T as males do. Here we expand on these results by focusing on sex differences in the production and performance of trills, i.e., rapid repetitions of song elements. We analyzed >42,000 trills recorded over a period of 6 weeks from 3 groups of castrated males and 3 groups of photoregressed females that received Silastic™ implants filled with T, T plus estradiol or left empty as control. Effects of T on the number of trills, trill duration and percent of time spent trilling were all stronger in males than females. Irrespective of endocrine treatment, trill performance assessed by vocal deviations from the trill rate versus trill bandwidth trade-off was also higher in males than in females. Finally, inter-individual differences in syrinx mass were positively correlated with specific features of trills in males but not in females. Given that T increases syrinx mass and syrinx fiber diameter in males but not in females, these data indicate that sex differences in trilling behavior are related to sex differences in syrinx mass and syrinx muscle fiber diameter that cannot be fully suppressed by sex steroids in adulthood. Sexual differentiation of behavior thus reflects organization not only of the brain but also of peripheral structures.

Enabling Edge-Cloud Video Analytics for Robotics Applications

Emerging deep learning-based video analytics tasks demand computation-intensive neural networks and powerful computing resources on the cloud to achieve high accuracy. Due to the latency requirement and limited network bandwidth, edge-cloud systems adaptively compress the data to strike a balance between overall analytics accuracy and bandwidth consumption. However, the degraded data leads to another issue of poor tail accuracy, which means the extremely low accuracy of a few semantic classes and video frames. Autonomous robotics applications especially value the tail accuracy performance but suffer using the prior edge-cloud systems. We present Runespoor, an edge-cloud video analytics system to manage the tail accuracy and enable emerging robotics applications. We train and deploy a super-resolution model tailored for the tail accuracy of analytics tasks on the server to significantly improves the performance on hard-to-detect classes and sophisticated frames. During online operation, we use an adaptive data rate controller to further improve the tail performance by instantly adjusting the data rate policy according to the video content. Our evaluation shows that Runespoor improves class-wise tail accuracy by up to 300%, frame-wise 90%/99% tail accuracy by up to 22%/54%, and greatly improves the overall accuracy and bandwidth trade-off.

Architecture for integrated RF photonic downconversion of electronic signals.

Electronic analog to digital converters (ADCs) are running up against the well-known bit depth versus bandwidth trade off. Towards this end, radio frequency (RF) photonic-enhanced ADCs have been the subject of interest for some time. Optical frequency comb technology has been used as a workhorse underlying many of these architectures. Unfortunately, such designs must generally grapple with size, weight, and power (SWaP) concerns, as well as frequency ambiguity issues which threaten to obscure critical spectral information of detected RF signals. In this work, we address these concerns via an RF photonic downconverter with potential for easy integration and field deployment by leveraging a novel, to the best of our knowledge, hybrid microcomb/electro-optic comb design.

Photocurrent-Summation-Based High-Speed Integrated Photonic Digital-to-Analog Converter

Achieving ultra high-speed arbitrary signal generation with conventional electronic digital-to-analog converters (DACs) is becoming extremely challenging, owing to the inherent bandwidth limitations due to interconnect and device parasitics in electronic circuits. Using optical techniques, and leveraging the advantages of photonic integration, a power-efficient solution for high-speed high-precision digital-to-analog conversion is proposed. A framework presenting resolution, power consumption and bandwidth tradeoffs for performance analysis of the photonic digital-to-analog converter (PDAC) with different configurations, is shown. The proposed PDAC concept is demonstrated in a proof-of-concept experimental setup, generating multi-level signals at up to 21.5 GBd.

On Rack-Aware Cooperative Regenerating Codes and Epsilon-MSCR Codes

In distributed storage systems, cooperative regenerating codes tradeoff storage for repair bandwidth in the case of multiple node failures. In rack-aware distributed storage systems, there is no cost associated with transferring symbols within a rack. Hence, the repair bandwidth will only take into account cross-rack transfer. Rack-aware regenerating codes for the case of single node failures have been studied and their repair bandwidth tradeoff characterized. In this paper, we consider the framework of rack-aware cooperative regenerating codes for the case of multiple node failures where the node failures are uniformly distributed among a certain number of racks. We characterize the storage repair-bandwidth tradeoff as well as derive the minimum storage and minimum repair bandwidth points of the tradeoff. We also provide explicit constructions of minimum bandwidth rack-aware cooperative regenerating codes and minimum storage rack-aware cooperative regenerating codes for a large range of parameters. We also consider another extension of minimum storage cooperative regenerating codes, in which we design slightly sub-optimal cooperative regenerating codes with much lower sub-packetization. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> -MSR codes are a class of codes introduced to tradeoff sub-packetization level for a slight increase in the repair bandwidth for the case of single node failures. We introduce the framework of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> -MSCR codes which allow for a similar tradeoff for the case of multiple node failures. We present a construction of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> -MSCR codes, which can recover from two node failures, by concatenating a class of MSCR codes and scalar linear codes. We give a repair procedure to repair the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> -MSCR codes in the event of two node failures and calculate the repair bandwidth for the same. We characterize the increase in repair bandwidth incurred by the method in comparison with the optimal repair bandwidth. Finally, we show the subpacketization level of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\epsilon $ </tex-math></inline-formula> -MSCR codes scales logarithmically in the number of nodes.

Meandered and Dispersion-Enhanced Planar Leaky-Wave Antenna With Fast Beam Scanning

Controlling the scan rate of frequency-scanned antennas can be useful for any bandwidth-limited application. Two techniques to control the scan rate of planar periodic leaky-wave antennas are discussed: optimizing unit cell dispersion and meandering unit cells with a desired periodicity. Each technique presents a tradeoff of limited matching bandwidth or reduced antenna gain, respectively. These techniques are used together to design a broadside-scanning Ka-band antenna. Measurements demonstrate a very high scan rate of 10.5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> /%BW. The 8$\%$ available bandwidth and 80 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> scan range through broadside is very favorable for frequency-scanned applications.

Review of CMOS Amplifiers for High Frequency Applications

The headway in electronics technology proffers user-friendly devices. The characteristics such as high integration, low power consumption, good noise immunity are the significant benefits that CMOS offer, paying many challenges simultaneously with it. The short channel effects and presence of parasitic which prevent speed pose questions on the performance parameters. A great sort of works has done by many groups in the design of the CMOS amplifier for high-frequency applications to discuss the parameters such as power consumption, high bandwidth, high speed and linearity trade-off to obtain an optimized output. A lot of amplifier topologies are experimented and discussed in the literature with its design and simulation. In this paper, the various efforts associated with CMOS amplifier circuit for high-frequency applications are studying extensively.

Development and demonstration of indoor three-dimensional localization using IR CMOS sensors for Mobile manipulators

A novel 3D localization scheme has been proposed for smart living or computer animation applications. This scheme utilizes two CMOS IR sensors originally used for Nintendo wiimote for performing stereo range finding on IR LEDs. Essential kinematics relations are developed to transform the detected pixel information into 3D spatial coordinates of IR LEDs. The sensing distance can be up to 3−4 meters and the localization scattering is characterized between 0.5 and 5 cm, depended on the sensing distance under proper setup. Such performance could actually satisfy the requirement in coarse navigation and motion planning of indoor mobile devices. Meanwhile, an Arduino-based IR LED switching technique for breaking the constraint on available Bluetooth communication channels is also proposed and implemented. By controlling the switching of IR LED units sequentially, the equivalent available channels can be extended with a tradeoff in system bandwidth. This 3D localization system can detect more IR LEDs than the number of original channels and each IR LED can be identified correctly even if it passes through a shelter. Several testing systems are setup for evaluating the performance on the 3D localization and the IR LED switching control, as well as for demonstrating the application potentials. The preliminary results indicate that the position of IR LEDs can be identified with sufficient accuracy and the system can also simultaneously detect more IR LEDs than the original limitation. With proper arrangement in deployment, it is possible to further increase the sensing zone to cover the entire indoor living space. This novel localization system is thus expected to have a great potential on applications such as mobile robots monitoring or human motion capture for animations.

Phase matching in two-dimensional coherent Raman imaging

Coherent anti-Stokes Raman scattering (CARS) is a valuable spectroscopic tool for the measurement of temperature and species concentration. In recent years, multi-dimensional CARS has seen focused development and is especially important in reacting flows. An important aspect of multi-dimensional CARS is the phase-matching scheme used. Historically, collinear and BOXCARS phase-matching schemes have been used to achieve phase matching over a broad spectral range. For 1-D and 2-D CARS imaging, two-beam or counter-propagating beam arrangements are necessary. The two-beam arrangement offers many advantages, but introduces a phase mismatch which limits the spectral response of the measurement. This work explores the tradeoffs in spatial resolution, spectral bandwidth, and CARS intensity in 2-D CARS arrangements. Calculations are made for two-beam and counter-propagating beam CARS.

Cascade Codes for Distributed Storage Systems

A novel coding scheme for exact repair-regenerating codes is presented in this paper. The codes proposed in this work can trade between the repair bandwidth of nodes (number of downloaded symbols from each surviving node in a repair process) and the required storage overhead of the system. These codes work for general system parameters $(n,k,d)$, which are the total number of nodes, the number of nodes suffice for data recovery, and the number of helper nodes in a repair process, respectively. The proposed construction offers a unified scheme to develop exact-repair regenerating codes for the entire trade-off, including the MBR and MSR points. We conjecture that the new storage-vs.-bandwidth trade-off achieved by the proposed codes is optimum. Some other key features of this code include: the construction is linear; the required field size is only $\Theta(n)$; and the code parameters and in particular sub-packetization level is at most $(d-k+1)^k$; which is independent of the number of the parity nodes. Moreover, the proposed repair mechanism is \emph{helper-independent}, that is the data sent from each helper only depends on the identity of the helper and failed nodes, but independent of the identity of other helper nodes participating in the repair process.

Millimeter-Wave Huygens’ Transmit Arrays Based on Coupled Metallic Resonators

A novel Huygens' transmit-array is proposed based on a coupled-resonator approach where two identical elliptical metallic patches with an elliptical hole separated by a dielectric substrate has been used to demonstrate millimeter-wave (mm-Wave) beam-forming for linear polarization. The proposed structure is simple and compatible with standard Printed Circuit Board (PCB) processes and utilizes a single dielectric substrate only. It is shown that by engineering the geometrical dimensions of the resonator, its electric (even-mode) and magnetic (odd-mode) resonances are excited in a balanced manner to achieve zero back-scattering in a large bandwidth. This operation principle of the proposed Huygens' cell is explained in details using both an insightful equivalent circuit model, as well as full-wave eigenmode analysis. Next, the proposed Huygens' cell is placed on top of a high gain 2D slot-array antenna, in its near-field, to engineer its aperture field distribution, where the resulting Huygens' transmit-array acts as a broadband phase plate. Several transmit-array prototypes designed around the 60 GHz frequency band are demonstrated and experimentally characterized in both their near and far-fields, to achieve difference pattern generation, beam expansion and beam steering as application examples, in addition to a uniform surface demonstrating its low-loss performance. Further discussions related to the unit cell size vs frequency bandwidth trade-offs and future extension to handling circular polarization are finally provided.

An Outer Bound for Linear Multi-Node Exact Repair Regenerating Codes

In distributed storage, erasure codes provide fault-tolerance while reducing the storage overhead compared to replication. The network traffic cost during the repair of node failures, called repair bandwidth, is an important metric in code design. Regenerating codes are a class of erasure codes developed with the aim of reducing the repair bandwidth while maintaining a high level of fault-tolerance. They exhibit a tradeoff between the storage overhead per node and the repair bandwidth. However, a fundamental understanding of the storage-repair bandwidth tradeoff under exact repair is open in general. In this work, we consider the exact repair problem of multiple failures in a centralized way. Building upon techniques from the literature, we first provide an alternative proof of the functional repair bound. Then, we derive a new outer bound for linear centralized multi-node exact repair codes and illustrate its performance under various parameter settings. The derived outer bound shows that, in general, the centralized multi-node functional repair tradeoff is not achievable under linear exact repair.

Spectral Efficiency Comparison Between Analog and Digital RoF for Mobile Fronthaul Transmission Link

Mobile fronthaul requires an efficient transfer of radio signals between cell-site remote radio heads (RRHs) and a centralized baseband unit (BBU) to satisfy diverse requirements on system capacity, latency, and cost. Both analog radio-over-fiber (A-RoF) and digital radio-over-fiber (D-RoF) enable the realization of the mobile fronthaul transmission link. A-RoF can achieve high spectral efficiency while it is susceptible to the noise and inherent nonlinearities during the optical transmission. Nevertheless, D-RoF can achieve high signal fidelity by using high quantization bits while it is commonly considered as low spectral efficiency. Therefore, the spectral efficiency comparison between D-RoF and A-RoF is generally not a fair one under the same constraint of the optical transmission link. In this paper, we theoretically analyze the recovered signal fidelity for D-RoF and A-RoF under the constraint of spectral efficiency and channel condition. We reveal that under the same channel condition, D-RoF can achieve the same spectral efficiency as A-RoF with the same recovered signal-to-noise ratio (SNR). Provided that D-RoF consumes more bandwidth, it offers the key advantage of D-RoF that the achievable SNR exhibits exponential improvement as a trade-off of the link bandwidth. If keeping the same quantization bits for radio signals, the required SNR threshold for D-RoF decreases exponentially with respect to the link bandwidth. Extensive experiments are carried out to confirm the theoretical analysis over the same constraint of the optical transmission link.

Cache Subsidies for an Optimal Memory for Bandwidth Tradeoff in the Access Network

While the cost of the access network could be considerably reduced by the use of caching, this is not currently happening because content providers (CPs), who alone have the detailed demand data required for optimal content placement, have no natural incentive to use them to minimize access network operator (ANO) expenditure. We argue that ANOs should therefore provide such an incentive in the form of direct subsidies paid to the CPs in proportion to the realized savings. We apply coalition game theory to design the required subsidy framework and propose a distributed algorithm, based on Lagrangian decomposition, allowing ANOs and CPs to collectively realize the optimal memory for bandwidth tradeoff. The considered access network is a cache hierarchy with per-CP central office caches, accessed by all ANOs, at the apex, and per-ANO dedicated bandwidth and storage resources at the lower levels, including wireless base stations, that must be shared by multiple CPs.

Storage and repair bandwidth tradeoff for heterogeneous cluster distributed storage systems

The storage and repair bandwidth tradeoff is an important issue in distributed storage systems (DSSs) where large scale data are stored in multiple nodes with erasure coding to ensure reliability. There are lots of studies on the DSS model with multiple clusters where the repair bandwidths from intra-cluster and cross-cluster nodes are differentiated to improve repair efficiency based on the realistic network topological structures. At the same time, separate nodes are also prevalent due to the variety of practical networks, but the work on the cluster DSS model with multiple separate nodes is insufficient, which is a main motivation of this paper. We formulate the tradeoff bound between storage repair bandwidth for a heterogeneous DSS model consisting of clusters and separate nodes by analyzing the min-cuts of heterogeneous information flow graphs corresponding to the orders of failed nodes. Additionally, the tradeoff bounds are investigated in multiple aspects when the repair bandwidth constraints and the amount of separate nodes vary, respectively. Moreover, a class of regenerating codes are illustrated to achieve the tradeoff in the heterogeneous cases.