Low Propagation Delay Research Articles

Exploiting Cloud Computing and Web Services to Achieve Data Consistency, Availability, and Partition Tolerance in the Large-Scale Pervasive Systems

This article presents a new comprehensive approach to realize a sufficient trade-off between the CAP properties (i.e., consistency, availability, and partition tolerance) in the large-scale pervasive information systems. To achieve these critical properties, the capabilities of both cloud computing and web services were exploited in developing the components of the proposed approach. These components include a cloud-based replication architecture for ensuring high data availability and achieving partition tolerance, a web services-based middleware for maintaining the eventual consistency, and a data caching scheme to enable the mobile computing elements to conduct update transactions during the disconnection periods. The evaluation of the performance aspects revealed that the proposed approach is able to achieve a load balance, lower propagation delay, and higher cache hit ratio, as compared to other baseline approaches.

Improved hetero-junction TFET-based Schmitt trigger designs for ultra-low-voltage VLSI applications

Purpose Tunnel field effect transistors (TFETs) have significantly steeper sub-threshold slope (24–30 mv/decade), as compared with the conventional metal–oxide–semiconductor field-effect transistors (MOSFETs), which have a sub-threshold slope of 60 mv/decade at room temperature. The steep sub-threshold slope of TFETs enables a much faster switching, making TFETs a better option than MOSFETs for low-voltage VLSI applications. The purpose of this paper is to present a novel hetero-junction TFET-based Schmitt triggers, which outperform the conventional complementary metal oxide semiconductor (CMOS) Schmitt triggers at low power supply voltage levels. Design/methodology/approach The conventional Schmitt trigger has been implemented with both MOSFETs and HTFETs for operation at a low-voltage level of 0.4 V and a target hysteresis width of 100 mV. Simulation results have indicated that the HTFET-based Schmitt trigger not only has significantly lower delays but also consumes lesser power as compared to the CMOS-based Schmitt trigger. The limitations of the conventional Schmitt trigger design have been analysed, and improved CMOS and CMOS–HTFET hybrid Schmitt trigger designs have been presented. Findings The conventional Schmitt trigger implemented with HTFETs has 99.9% lower propagation delay (29ps) and 41.2% lesser power requirement (4.7 nW) than the analogous CMOS Schmitt trigger, which has a delay of 36 ns and consumes 8 nW of power. An improved Schmitt trigger design has been proposed which has a transistor count of only six as compared to the eight transistors required in the conventional design. The proposed improved Schmitt trigger design, when implemented with only CMOS devices enable a reduction of power delay product (PDP) by 98.4% with respect to the CMOS conventional Schmitt trigger design. The proposed CMOS–HTFET hybrid Schmitt trigger further helps in decreasing the delay of the improved CMOS-only Schmitt trigger by 70% and PDP by 21%. Originality/value The unique advantage of very steep sub-threshold slope of HTFETs has been used to improve the performance of the conventional Schmitt trigger circuit. Novel CMOS-only and CMOS–HTFET hybrid improved Schmitt trigger designs have been proposed which requires lesser number of transistors (saving 70% chip area) for implementation and has significantly lower delays and power requirement than the conventional designs.

Joint optimization based satellite handover strategy for low earth orbit satellite networks

Low earth orbit constellation satellite communication has the characteristics of low propagation delay, low path loss, low launch cost and wide range of applications. Due to the low orbital altitude and the short orbital period of low earth orbit satellites, the relative position between satellites and gateway stations changes fast. As a result, the links between gateway stations and satellites need to be switched continuously. Based on the minimum handover frequency algorithm, this paper considers the balance of satellite workloads, and proposes a load balanced satellite handover strategy. In the proposed handover strategy, a joint optimization algorithm is employed, and the power allocation of the satellite is optimized to improve the system capacity. In the multi-satellite connection model, an adaptive power allocation algorithm is proposed to guarantee the service quality of the system. Simulation results demonstrate the efficiency of the proposed satellite handover strategy.

Design and analysis of photonic crystal ring resonator based 6 × 6 wavelength router for photonic integrated circuits

A photonic crystal ring resonator-based 6 × 6 router has been designed and reported. The router is designed using silicon pillars with a refractive index of 3.47 perforated in the air background of refractive index 1 in a square lattice with a lattice constant of a = 562 nm. The router is designed to operate in the third optical window wavelength which has low loss and most widely used in optical communication systems and networks. Plane-wave expansion and finite difference time domain method has been used to obtain the bandgap and performance of the designed router, which exhibits acceptable performance such as low insertion loss, low propagation delay, and low crosstalk. These routers will find applications in the photonic integrated circuit that paves a path to all-optical networks.

A Balanced Routing Protocol Based on Machine Learning for Underwater Sensor Networks

An underwater sensor network (UWSN) is a wireless network that is deployed in oceans, seas, and rivers for real-time exploration of environmental conditions. The network is used to measure temperature, pressure, water pollution, oxygen level, volcanic activity, floods, and water streams. Although radio frequency (RF) is widely utilized in wireless networks, it is incompatible with the UWSN environment; therefore, other communication mechanisms have been employed to manage the underwater wireless communication among sensors, such as acoustic channels, optical waves, or magnetic induction (MI). Unlike terrestrial wireless sensor networks, UWSNs are dynamic, and sensors move according to water activity. Therefore, the network topology changes rapidly. One of the most critical challenges in UWSNs is how to collect and route the sensed data from the distributed sensors to the sink node. Unfortunately, the direct application of efficient and well-established terrestrial routing protocols is not possible in UWSNs. In this work, a balanced routing protocol based on machine learning for underwater sensor networks (BRP-ML) is proposed that considers the UWSN environmental characteristics, such as power limitations and latency, while considering the void area issue. It is based on reinforcement learning (Q-learning), which aims to reduce the network latency and energy consumption of UWSNs. The communication technique in the proposed protocol is based on the MI technique, which has many advantages, such as steady and predictable channel response and low signal propagation delay. The simulation findings validated that BRP-ML reduced latency by 18% and increased energy efficiency by 16% compared to QELAR.

A study of utilization of magnetic induction for underwater communication

The vast bulk of underwater communication research has focused on acoustic communication. High propagation delays, extremely low data rates, and very environment-dependent channel behavior are among issues that acoustic communication encounters. To solve these flaws, magnetic induction is proposed as a viable communication paradigm for underwater applications in this paper. All research obstacles in this area are described, according to this. Underwater MI communications are fundamentally distinct from traditional underwater communication paradigms, which depend on electromagnetic, acoustic, or optical waves to convey information between transmitting and receiving parties. MI-based underwater communications have a number of unique and promising characteristics, including low signal propagation delay, reliable and consistent channel behaviour, a sufficiently long communication range with high bandwidth, and the ability to operate silently and stealthily underwater. This article presents the foundations of underwater MI communications, including MI channel models, MI networking protocols design, and MI-based underwater localization, in order to fully use the promise aspects of MI-based communications under water.

Adaptive Power Control Aware Depth Routing in Underwater Sensor Networks

Underwater acoustic sensor network (UASN) refers to a procedure that promotes a broad spectrum of aquatic applications. UASNs can be practically applied in seismic checking, ocean mine identification, resource exploration, pollution checking, and disaster avoidance. UASN confronts many difficulties and issues, such as low bandwidth, node movements, propagation delay, 3D arrangement, energy limitation, and high-cost production and arrangement costs caused by antagonistic underwater situations. Underwater wireless sensor networks (UWSNs) are considered a major issue being encountered in energy management because of the limited battery power of their nodes. Moreover, the harsh underwater environment requires vendors to design and deploy energy-hungry devices to fulfil the communication requirements and maintain an acceptable quality of service. Moreover, increased transmission power levels result in higher channel interference, thereby increasing packet loss. Considering the facts mentioned above, this research presents a controlled transmission power-based sparsity-aware energy-efficient clustering in UWSNs. The contributions of this technique is threefold. First, it uses the adaptive power control mechanism to utilize the sensor nodes’ battery and reduce channel interference effectively. Second, thresholds are defined to ensure successful communication. Third, clustering can be implemented in dense areas to decrease the repetitive transmission that ultimately affects the energy consumption of nodes and interference significantly. Additionally, mobile sinks are deployed to gather information locally to achieve the previously mentioned benefits. The suggested protocol is meticulously examined through extensive simulations and is validated through comparison with other advanced UWSN strategies. Findings show that the suggested protocol outperforms other procedures in terms of network lifetime and packet delivery ratio.

EdgeRouting: Using Compute Nodes in Proximity to Route IoT Data

Due to the proliferation of edge computing, cloud providers have started offering compute nodes at the edge of the network in addition to traditional compute nodes in data centers. So far, various systems have been proposed for processing Internet of Things (IoT) data on both edge and cloud compute nodes in order to reduce the communication latency. However, such systems do not typically consider that the network bandwidth between an edge node and a cloud node can be orders of magnitude higher than the bandwidth between an IoT device and a cloud node. As a result, the IoT data are commonly sent selectively to either edge or cloud nodes disregarding alternative network paths through edge nodes, which may have higher network bandwidth, and lower communication latency. To avoid this, in this paper we analyze the latency of sending data to edge and cloud compute nodes of cloud providers. Based on this analysis, we propose edgeRouting which routes the data through the closest edge compute node. By doing that, edgeRouting exploits both the low propagation delay of nodes at the edge, and the high bandwidth among edge and cloud compute nodes of cloud providers. To evaluate our approach, we perform experiments on a real-world setup with nearby and remote compute nodes of a cloud provider, and we show that edgeRouting reduces the communication latency by up to 55% compared to alternative methods.

Social-aware spectrum sharing for D2D communication by artificial bee colony optimization

Next-generation cellular networks must handle an increasing demand for data transmission resources, which requires the study of new technologies, such as Device-to-Device (D2D) communications. D2D expands the use of resources from a location perspective, and takes advantage of the geographical proximity of users to perform data transmission at high rates and low propagation delays. On the other hand, the widespread use of social networks establishes the degree of social relations among users and facilitates the efficient management of D2D communication networks. The integration of social networks and D2D communications into 5G networks has posed important challenges (e.g., exploitation of the social relationships of mobile users and management of interference and resources towards a better performance of D2D communications). This article proposes a social-aware Radio Resource Allocation (RRA) optimization solution for D2D communications in 5G networks that considers partial Channel State Information (CSI). A selected-NM Maximum Distance Ratio (MDR) q-bit feedback scheme designed reduces feedback overhead, since each D2D receiver sends only q-bit feedback CSI of N cellular User Equipment (CUE) and M D2D pairs with the largest MDR metric. The RRA problem is solved by an Artificial Bee Colony (ABC) algorithm for the obtaining of number of D2D connections in each evolved NodeB (eNB) and maximization of the system throughput.

Study and Implementation of 600-V High-Voltage Gate Driver IC With the Common-Mode Dual-Interlock Technique for GaN Devices

Gallium nitride (GaN) power device is well known as a favorable alternative of silicon power device for the power management system. However, it is difficult to meet the demand of higher operating frequency when using the traditional high-voltage gate driver IC (HVIC) to control the GaN devices. In this article, we illustrated that the propagation delay of the high-voltage level-shifter structure is the primary factor in limiting the operating frequency of the HVIC, and a new high-voltage level-shifter structure named common-mode dual-interlock (CMDI) level-shifter structure is proposed, which can eliminate both the common-mode transient noise and differential-mode transient noise effectively without adopting resistance-capacitance noise filter. A better tradeoff between the dVS/dt noise immunity capability and the propagation delay can be achieved, which is verified by the numerous theoretical analysis and experimental results. Due to all, the GaN integration technology is not suitable for complicated circuits at present, a 600 V HVIC for GaN device adopting the proposed CMDI level-shifter structure is implemented with normal silicon-based bipolar-CMOS- double-diffused MOSFET (DMOS) technology finally. The experimental results show that it can achieve high dVS/dt noise immunity larger than 100 V/ns, low propagation delay less than 32 ns, and the allowable negative VS swing to -4 V at 5 V supply voltage.

TCP Incast in Data Center Networks: Issue and Existing Solutions

Data centers networks supports heterogeneous kind of applications like social networking, e-commerce, web search, video data hosting, computation-intensive and data-storage. It has high-bandwidth links, low propagation delay and commodity switches with small-size buffers. Under cluster-based storage environment, data center supports barrier-synchronized many-to-one communication pattern where multiple worker nodes simultaneously transmit bulk of data to single aggregator node by running standard TCP protocol. This synchronized transmission may overload aggregator’s switch buffer, which leads to severe packet loss and overall throughput fall. This is called as TCP Incast problem. This paper analyses issue of TCP Incast and provides detailed survey about several solutions at link, transport and application layer to mitigate impact of TCP Incast in data center network. Solutions are described with their procedural approach for alleviating Incast. Comparative evaluation between these solutions provides understanding about their merits, demerits and applicability under various implementation circumstances.

Diversity technique evaluation for LTE high mobility user based on high altitude platform

HAPS (High Altitude Platform Station) is an alternative technology of communication system that utilizes terrestrial and satellite systems. HAPS technology is located in the stratosphere layer with the height of 17-22 km above the earth’s surface. HAPS has some advantages, which are wide range area, communication ability on line of sight (LOS), and low propagation delay. In this paper we present the comparison between single HAPS system and two HAPS diversity technique. From simulation result, it is evident that using two HAPS as a diversity technique gives better performance than the single HAPS system, it is shown by how the two HAPS diversity technique requires less SNR than the single HAPS system, typically 3 dB less of SNR.

SiC MOSFETs Gate Driver With Minimum Propagation Delay Time and Auxiliary Power Supply With Wide Input Voltage Range for High-Temperature Applications

Low propagation delay time is essential for SiC drivers at high frequency. The propagation delay time of the commercial parts is normally over 100 ns. A signal isolation circuit and a level shifting circuit are proposed and applied in SiC drivers with minimum propagation delay time. The narrow edge signals of the input pulsewidth modulation (PWM) signal are extracted by nondelay RC differential circuits in the control side and demodulated by an RS flip-flop in the drive side so that only two low-profile transformers are used for low-delay signal isolation. A two-stage isolated auxiliary power supply without linear optocouplers is proposed in order to realize wide input voltage range and wide operation temperature range. Wide input voltage range is achieved by forward- feedback control. The experimental results verify the proposed driver advantages. The propagation delay time at 400 kHz is 49.6 ns for the rising edge and 18.4 ns for the falling edge, which are reduced by over 50% compared with the commercial parts. The prototype is tested under the ambient temperature of 85 °C with the 9–18-V input auxiliary power supply. Considering the temperature rise of 28 °C, the operation temperature of the power supply is 113 °C.

A 1 V, 0.53 ns, 59 μW Current Comparator Using Standard 0.18 μm CMOS Technology

This letter aim to propose a current comparator based on simple current mirror which use single amplifier to reduce input offset, the improving symmetry current comparator achieve lower propagation delay (0.53 ns at input current $$I = 10\,{\upmu }$$A) and lower power dissipation (59 $${\upmu }$$W at SS corner) by comparing proposed structure at the supply voltage of 1 V, circuit simulations are performed in cadence software and hspice for a 0.18 $${\upmu }$$m TSMC standard CMOS process.

A Miniaturized Low-Intensity Ultrasound Device for Wearable Medical Therapeutic Applications.

Low-intensity ultrasound has drawn increasing attention recently as a non-invasive modality for medical therapeutic applications. Current commercially available low-intensity ultrasound devices are bulky and expensive. In this paper, a battery-powered miniaturized device is proposed to generate low-intensity therapeutic ultrasound. The proposed device consists of a custom Application-Specific Integrated Circuit (ASIC), an off-chip digital control block, and a piezoelectric transducer. The ASIC, which integrates a DC-DC boost converter and a transducer driver, is implemented in TSMC's 0.18 μm BCD Gen2 process. Measurement results show that a maximum output voltage of 14V is achieved by the proposed fully-integrated DC-DC boost converter with a battery supply voltage of 3.7V. The peak power conversion efficiency is 29% and the output power at the peak power conversion efficiency is 105mW. The on-chip transducer driver employs a half-bridge circuit with two n-type devices at the output stage. A high-voltage level shifter with low power consumption and short propagation delay is proposed in this paper for the high-performance operation of the half-bridge transducer driver. The piezoelectric transducer is a customized transducer with a resonance frequency of 1.5MHz. At this frequency, the proposed low-intensity ultrasound device is able to generate continuous-wave ultrasound with a therapeutic power intensity of 32 [Formula: see text]. The proposed low-intensity ultrasound device is low-cost, compact, and light-weight, which enables affordable, and wearable applications.

A 4:1 Multiplexer using dual chirality CNTFET-based domino logic in nano-scale technology

ABSTRACTThis paper proposes a 4:1 Multiplexer (MUX) designed using proposed Dual Chirality High-Speed Noise Immune Domino Logic (DCHSNIDL) technique for designing lower delay noise immune domino logic circuits in Carbon Nanotube Field Effect Transistors (CNTFETs) technology. Dynamic power consumption, speed and noise immunity of the circuit are improved by changing the threshold voltage of the CNTFETs. The chirality indices of the carbon nanotubes (CNTs) are varied to change the threshold voltage of the CNTFETs. Simulations are carried out for 32 nm Stanford CNTFET model in HSPICE for 2-, 4-, 8- and 16-input domino OR gates at a clock frequency of 200 MHz on a DC supply voltage of 0.9V. The proposed DCHSNIDL domino circuit reduces power consumption by a maximum of 61.77% and propagation delay by a maximum of 55.11% compared to Current-Mirror Based Process Variation Tolerant (CPVT) circuit in CNTFET technology. The proposed CNTFET-based domino technique shows a maximum reduction of 96.31% in power consumption compared to its equivalent circuit in CMOS technology for a 4-input OR gate. The proposed technique shows an improvement of 1.04× to 1.35× times in Unity Noise Gain (UNG) compared to various existing techniques in CNTFET technology. The 4:1 MUX designed using proposed technique has 48.91% lower propagation delay and consumes 52.80% lower power compared to MUX using CPVT technique.

Effect of Torsional Beam Length on Acoustic Functionalities of Bio-Inspired Piezoelectric MEMS Directional Microphone

In MEMS, the vibrations of torsionally supported diaphragms largely depend on the torsional beam specifications. An amiss selection of the beam parameters can lead to significant imperfection in the microphone functionalities, such as modal frequency, sensitivity, directionality, signal-to-noise ratio (SNR), and input-referred noise floor. Here, we present two piezoelectric MEMS directional microphones inspired by the ear anatomy of fly Ormia ochracea, with a prime focus to identify the effect of torsional beam dimensions on their acoustic functionalities. The dimensions of both diaphragms and the width & thickness of the torsional beams are identical for both microphones, the only difference between these two microphones lies in the torsional beam length. The microphones are fabricated by a commercially available micromachining process; PiezoMUMPs. To convert the mechanical vibrations into the electronic signal, a unique piezoelectric sensing scheme is developed comprising of aluminium nitride (AlN) and D33 transducer mode. The performances of both microphones are carried out by the theoretical analysis and simulation and further verified with the experimental measurements. It is found from all analyses that the microphone having a shorter length of the torsional beam is better in terms of sensitivity, noise floor, and SNR regarding its low propagation delay.

5G-Slicing-Enabled Scalable SDN Core Network: Toward an Ultra-Low Latency of Autonomous Driving Service

5G networks are anticipated to support a plethora of innovative and promising network services. These services have heterogeneous performance requirements (e.g., high-rate traffic, low latency, and high reliability). To meet them, 5G networks are entailed to endorse flexibility that can be fulfilled through the deployment of new emerging technologies, mainly software-defined networking (SDN), network functions virtualization (NFV), and network slicing. In this paper, we focus on an interesting automotive vertical use case: autonomous vehicles. Our aim is to enhance the quality of service of autonomous driving application. To this end, we design a framework that uses the aforementioned technologies to enhance the quality of service of the autonomous driving application. The framework is made of 1) a distributed and scalable SDN core network architecture that deploys fog, edge and cloud computing technologies; 2) a network slicing function that maps autonomous driving functionalities into service slices; and 3) a network and service slicing system model that promotes a four-layer logical architecture to improve the transmission efficiency and satisfy the low latency constraint. In addition, we present a theoretical analysis of the propagation delay and the handling latency based on GI/M/1 queuing system. Simulation results show that our framework meets the low-latency requirement of the autonomous driving application as it incurs low propagation delay and handling latency for autonomous driving traffic compared to best-effort traffic.

A Charging-Aware Multi-Mode Routing Protocol for Data Collection in Wireless Rechargeable Sensor Networks.

This paper proposes a charging-aware multi-mode routing protocol (CMRP) to collect data in the wireless rechargeable sensor networks. The routing mechanism in CMRP is not steady but changes according to the energy charging status of sensors. Sensors that cannot replenish their energy efficiency use the routing protocol with less energy consumption. On the contrary, sensors that can replenish their energy use the low propagation delay routing protocol. A novel heuristic chaining mechanism based on multi-level convex hull circle (MCC) is also proposed. Simulation results show that CMRP not only has longer operation time than LEACH and PEGASIS but also has the shortest propagation delay time. The lifetime of CMRP is less than the minimum spanning tree by about 1%, but the propagation delay is shorter than MSTP about 21–28%. In addition, CMRP considers both reducing energy consumption and shortening the propagation delay at the same time. The life-delay rate of the CMRP is close to the optimal results.

A Power-Delay and Area Efficient Voltage Level Shifter Based on a Reflected-Output Wilson Current Mirror Level Shifter

This brief presents an area-efficient and ultra-low power high-speed voltage level shifter (LS) based on a reflected-output Wilson current mirror LS (WCMLS). The proposed technique removes the limitation of conventional WCMLS in using a current mirror with extremely high sizing ratio significantly saving area and power. Compared to the state-of-the-art counterparts, the proposed LS comprises relatively fewer elements all minimum sized further reducing the area. The proposed LS operates well with extremely sub-threshold input voltages while exhibiting considerably lower propagation delay. Implemented in a standard $0.18-\mu \text{m}$ CMOS process, post-layout simulations confirm that the proposed subthreshold LS can effectively transform input voltage levels as low as 50 mV to about 1.8 V at output without employing any multi-threshold devices. With an area of $7.5\,\,\mu \text{m}\,\,\times \,\,4.7\,\,\mu \text{m}$ , the overall delay and power consumption of the proposed LS for a 0.4 V/1 MHz input signal and 1.8 V output level are 6.1 ns and 76.34 nW, respectively.