Bandwidth Delay Research Articles

Optimal packet routing for wireless body area network using software defined network to handle medical emergency

<span lang="EN-US">The packet forwarding node selection is one of the main constraints in the Software Defined Network (SDN). To improve the network performance, the SDN controller has to choose the shortest and optimised path between source and destination in routine and emergency packet transmission. In e-health service, information of the emergency patient has to be transferred immediately to remote hospitals or doctors by using efficient packet routing approach in Wireless Body Area Network (WBAN). In WBAN, to improve the packet transmission, the optimal packet routing policy developed based on packets priority with the support of a greedy algorithm for SDN. The SDN Controller selects the forwarding node based on node propagation delay and available bandwidth between two forwarding nodes. The mesh network topology network created for implementation, implementation results are compared with existing research works. Finally, this algorithm implemented in our institution, Software defined communication testbed laboratory (SDCTestbed Lab) with the support of 13 Zodiac-Fx (Forwarding device), 2 Raspberry-Pi3 B+ Model (host) and Arduino kit (sensor node).</span>

An Overview of Enhance Bandwidth Management in Cellular Network

cellular networks have changed our life. However, current cellular network does not have an efficient bandwidth management during congestion. Some of these techniques was used have a few drawbacks such as the performance of the handoff mechanism depends on the channel quality, QoS, bandwidth, delay and speed of the cellular node, the handoff optimizing tend to increase the ping-pong handoff rate, frequency and bandwidth. The paper indicates the promising factors of the handoff mechanisms as decrease delay, enhance speed, saving energy and control bandwidth to achieve better throughput in wireless networks as compared to predecessor networks. How limited bandwidth are segregated among nodes is discussed in details in this paper. We believe that having implemented the proposed enhanced bandwidth management, congestion in current cellular network can perform better.

Modal delay and modal bandwidth measurements of bi-modal optical fibers through a frequency domain method

Abstract We propose a simple and robust frequency domain method for measuring modal delay and bandwidth of bi-modal optical fibers. An analytical transfer function model is formulated showing excellent agreement with experimental results for relatively short fibers. Using the model, a full set of information can be extracted, including modal delay and modal bandwidth under any launch conditions. As a result, one can obtain a worst-case modal bandwidth that can gauge the fiber modal bandwidth under general conditions. In addition, the frequency domain measurement method and the analytical model are validated through the excellent agreements with the time domain measurement results. The analytical model is also generalized for longer fiber lengths when additional degradation effects become significant to alter the behavior of the transfer function. Through the detailed study, we show that the simple frequency domain measurement method as facilitated by the analytical model can deliver a full set of modal delay and modal bandwidth information that otherwise requires more complex method of differential mode delay measurements.

Slow light with high normalized delay-bandwidth product in organic photonic crystal coupled-cavity waveguide.

In this theoretical study, a photonic crystal coupled-cavity waveguide created on polymer substrate was demonstrated to provide high-performance slow light with low group-velocity dispersion and large normalized delay-bandwidth product. Combined with structural-parameter optimization, the normalized delay-bandwidth product was enhanced to a large value of 0.809, and the group-velocity dispersion was on the order of 104(ps2/km). Furthermore, the optimized coupled-cavity waveguide had tunability capabilities by changing the external pump laser power. Importantly, while adjusting the slow light, the normalized delay-bandwidth product values remained above 0.8, which was necessary to maintain the performance of optical buffering devices.

LAVR: link failure avoidance and void recovery routing protocol for underwater sensor networks

Recently, underwater wireless sensor network (UWSN) has paved the way for researchers towards a new era of exploring ocean realm targeting envisioned landscape of underwater applications. These applications can be made viable through underwater communication by using acoustic waves, giving rise to several design challenges like limited bandwidth, large and variable propagation delay, frequent connectivity loss, etc. Reliable data delivery in UWSN is always a tempting issue to be addressed, which is jeopardised by link failures and communication void. Under this context, Link failure Avoidance and Void Recovery (LAVR) routing protocol is proposed that uses link quality as forwarding factor, computed using Triangle Metric, to achieve reliability. A void node recovery procedure is proposed to displace the void node to a new depth to increase the packet delivery ratio. Simulations are performed in Aqua-Sim simulator and LAVR outperforms other existing protocols in terms of packet delivery ratio and network lifetime.

Time delay signature and bandwidth of chaotic laser output from semiconductor laser

<sec> Semiconductor laser (SL) can output chaotic lasers under external disturbances such as optical injection or optical feedback, and the bandwidth can reach up to GHz magnitude. External-cavity feedback semiconductor lasers can output high-dimensional chaotic lasers and are considered to be better sources of chaotic entropy. However, due to external cavity feedback and other effects, it will give rise to obvious external cavity time delay signature (TDS) in the output chaotic laser, which restricts the application of chaotic lasers. On the other hand, the bandwidth of chaotic laser determines the transmission rate of confidential communication, and therefore TDS and bandwidth are two important parameters that will affect chaotic laser’s applications. Therefore, it is significant to take appropriate measures to suppress the TDS and increase the bandwidth of chaotic laser output by semiconductor laser. </sec><sec> In this paper the output laser from a semiconductor laser with single optical feedback is partially injected to another semiconductor laser with double filtered optical feedback. Thus they form a semiconductor laser system with external optical injection and double filtered optical feedback, i.e. a master-slave laser system which is used to suppress the TDS of chaotic laser and investigate its bandwidth. We numerically investigate the influences of external light injection coefficient, feedback intensity, pumping factor, and filter bandwidth on TDS. Then the suppression effects of this system on TDS are analyzed and compared with those of semiconductor laser system with external optical injection and single optical feedback, those of semiconductor laser system with external optical injection and double optical feedback, those of semiconductor laser system with external optical injection and single filtered optical feedback, and those of semiconductor laser system with double filtered optical feedback. The results show that the proposed scheme in this paper has the best suppression effect on TDS. Then the bandwidth of the chaotic laser output from the system is investigated under the condition of parameters of effectively suppressing TDS. The results show that the system proposed in this paper can increase the bandwidth of the system output chaotic laser by properly selecting the parametric values, and the maximum bandwidth value of the obtained chaotic laser is about 8.8 GHz. The above investigations indicate the effectiveness of the proposed scheme. The results of this investigation are significant for the application of chaotic lasers. </sec>

Tension Networked Control Strategy for Carbon Fiber Multilayer Diagonal Loom

With the aim of solving warp tension control problems in the let-off system and opening system in the carbon fiber multilayer diagonal loom, dynamic models of warp tension are established in this study based on dynamic analysis. Adaptive fuzzy PID control is applied to the tension-networked control, and an adaptive fuzzy PID controller is designed to solve the problems of network induced delay, packet loss, and network bandwidth occupancy. A TrueTime simulation structure of the tension control system is also built. Compared with PID control, adaptive fuzzy PID control exhibited the advantages of a small overshoot, small fluctuation of output tension, good tracking effect, and stability in simulations under different conditions, including a 30-ms network induced delay, 10% packet loss, and 30% network bandwidth occupancy. The results of the simulations show that adaptive fuzzy PID control has better control effect than PID control, and is more suitable for tension-networked control systems in the carbon fiber multilayer diagonal loom.

Research on Communication Network Configuration and Simulation of Smart Substation Based on Ethernet

The characters of the intelligent substation communication network structure are analyzed in the paper. Combining existing integrated automation substation hardware circuit and VLAN (Virtual Local Area Network) research foundation to optimize the network configuration. In accordance with IEC61850 standard, the network is partitioned into several VLANs based on the Tag VLAN division method of ID address. Real-time communication packets between GOOSE networks, SV (sampling information) networks, and switches use 802.1Q protocol headers to distinguish these packets. Finally, OPNET simulation software was used to simulate and verify the simplified dual-star topology. The results demonstrate that the delay and traffic bandwidth meet the requirements of actual substation operation standards. Compared with ordinary single-star networks, the reliability is greatly improved and the effectiveness is improved.

Fair Resource Allocation Based on User Satisfaction in Multi-OLT Virtual Passive Optical Network

In this paper, a fair resource allocation mechanism based on user satisfaction in multiple optical line terminal (multi-OLT) virtual passive optical network (VPON) is proposed. By introducing user satisfaction functions, the satisfaction of users can be quantified. By presenting multi-OLT VPON in metro-access optical network (MAON), different priority services can be effectively handled separately. Based on user satisfaction, a fair resource allocation mechanism called double fair dynamic bandwidth allocation scheme (DFDBAS) is proposed. DFDBAS is a combination of two algorithms: wavelength fair allocation (WFA) algorithm and timeslot fair allocation (TFA) algorithm. In TFA algorithm, max-min fairness (MMF) algorithm is presented to allocate bandwidth for high priority service and Lagrange multiplier method is implemented to allocate bandwidth for low priority service. By implementing DFDBAS, not only user delay satisfaction can be improved, but also user bandwidth satisfaction can increase. By the simulation and analysis, the effectiveness of the proposed algorithms is demonstrated. Compared with modified limited service (LS) algorithm, DFDBAS makes both delay satisfaction and bandwidth satisfaction increase by at least 30% when the load is greater than 1.

Simulation of dynamically tunable and switchable electromagnetically induced transparency analogue based on metal-graphene hybrid metamaterial

A planar terahertz electromagnetically induced transparency-like (EIT-like) metamaterial, comprising an outer circular ring resonator (CRS) made by graphene, an inner vertical two-gap circular split ring resonator (VSRR) and a smaller horizontal two-gap circular split ring resonator (HSRR), is proposed. A distinct transparency window can be observed in two perpendicular polarization directions, respectively. By tuning the Fermi energy, the maximum modulation depths in two perpendicular polarization directions respectively can reach up to 83.54% and 94.39%. Meanwhile, the EIT-like effect, amplitude of transparency window, group delay and delay bandwidth product (DBP) can be adjusted dynamically without shift of frequency. The surface currents and three-level Λ-type system can explain the physical mechanism of EIT-like effect. The analytical results based on a two-particle model are in good agreement with the numerical results. Our work provides a new method for dynamically adjustable terahertz slow light devices, which makes the graphene more controllable in metal-graphene hybrid structure.

Efficient upstream bandwidth utilization with minimum bandwidth waste for time and wavelength division passive optical network

For an efficient bandwidth management among the optical network units in the upstream link of a passive optical network (PON), it is necessary to use a dynamic bandwidth assignment (DBA) scheme at the optical line terminal. This is really helpful for the PON service providers in meeting their delay guarantees and bandwidth commitments as per the service level agreements (SLAs). It also enables them to increase their revenue by accommodating more users in the available bandwidth. This study investigates the weaknesses of existing ITU compliant DBA schemes. The study reviews the earlier reported work on DBA with a focus on the ITU compliant schemes. The study argues that the existing reported schemes suffer from a few deficiencies such as inefficient bandwidth reporting in their polling process and borrow refund problem while utilizing the unused bandwidth (UBW). To overcome these shortcomings, an efficient bandwidth assignment (EBA) scheme is presented. Extensive simulations are performed to test the performance of the proposed scheme with both Poisson distributed and self-similar traffic patterns. The results show that the EBA scheme efficiently utilizes the UBW and RSB leading up to 80%, 90%, 60% and 99% lesser upstream delays with Poisson traffic pattern and up to 80%, 77% and 99% lesser delay with self-similar traffic compared to GREAL, IACG, and GIANT schemes. However, compared to EBU it shows up to 12% higher delay values due to reduction of its RSB share because of the utilization of UBW by T3 and T4. Overall, compared to other schemes, EBA exhibits least bandwidth waste per cycle resulting in least US delays. The bandwidth waste in EBA is also minimized due to least unallocated bandwidth ratio and frame loss rate. The maximum US delays of all traffic classes for EBA remains under 2 ms for T2 and T3 till the traffic load of 1 and till the load of 0.8 for T4 traffic class.

Performance Evaluation of a MIMO based Underwater Communication System under Fading Conditions

Due to the intense importance of underwater applications in military and commercial purposes, Underwater Acoustic Communication (UWAC) is an attracting research area. Very high propagation delay, path loss, and low bandwidth are the factors that challenged the acoustic waves in an underwater environment. Multi-input multi-output (MIMO) techniques are currently considered in UWAC to surpass the bandwidth limitation of the undersea channel. In this paper, the accomplishment of a MIMO in UWAC System highlighting both Line of Sight (LOS), i.e. the Rician fading and Non-Line of Sight (NLOS), i.e. the Rayleigh fading signal propagation, is assessed. Spatial Modulation technique is used, which helps in increasing the data rate in UWAC. It controls the spatial distribution of the energy caused by a signal in such a way that the single ocean channel sustains multiple parallel communication channels. The utilization of Zero Forcing (ZF) equalizer, which estimates the transmitted data proves the success of removing inter symbol interference (ISI). Matlab simulations are done for the UWAC system for values of LOS/NLOS. Because of various scattering effects in NLOS propagation, the error rate is considerably high when compared to that of the LOS propagation. Bit Error Rate (BER) values for the corresponding signal to noise ratio (SNR) are calculated.

Service Differentiated QOS Guaranteed Cross Layer Solution for Underwater Acoustic Sensor Networks (SD-QCLS)

Physical characteristics limits the capability of sensor network in case of underwater deployment. Factors like medium delay, doppler spreads and limited bandwidth are challengers to achieve a QoS (Quality of Service) guarantee in under water acoustic sensor networks. Under these conditions maximizing the bandwidth availability with consideration for application traffic requirements is important. This work proposes a service differentiated QOS guaranteed cross layer solution to maximize the available bandwidth and life time of the network under the constraints of application traffic requirements. At all different layers of IEEE 802.15.4 protocol stack, i.e., Application Layer, Session Layer, Network Layer, MAC Layer, and PHY Layer, the solution uses network parametes to optimize available bandwidth and also QoS. The solution involves redundancy and prediction based content coding at application layer, QoS based rate control at session layer, load based routing, transmission range adjustment at physical layer for guaranteed QoS delivery over acoustic sensor network.

Research Scope and Tools for Workflow Scheduling in Cloud Environment

Workflow is a prototype that executes the behavior of scientific and engineering applications for which the sequence of tasks needs to be automated based on the input parameters specified. Difficulties arise for CSPs primarily during the execution environment due to its direct impact on various QoS parameters. Existing workflow scheduling techniques has research focus with dimensions that include undetermined demands, task failure,l delay cost, ambiguous deadlines, bandwidth, cache inclusion, scheduler policies, VM cycles, QoS impact, OS support, fault-tolerant and virtualization level. The comparative analysis made in this paper for workflow scheduling strategies and tools used in the cloud environment towards QoS parameters would have a greater impact on industry task automation which in turn provides the researchers to set their objectives and tools to be used in-order to bring forth new approaches and solutions. This paper can be extended considering the research scope given in the comparative analysis and the data size pertaining to each task in workflow and data migration issues which cannot be done without cost, legal policies and technical issues.

An offloading scheme leveraging on neighboring node resources for edge computing over fiber-wireless (FiWi) access networks

The computation resources at a single node in Edge Computing (EC) are commonly limited, which cannot execute large scale computation tasks. To face the challenge, an Offloading scheme leveraging on NEighboring node Resources (ONER) for EC over Fiber-Wireless (FiWi) access networks is proposed in this paper. In the ONER scheme, the FiWi network connects edge computing nodes with fiber and converges wireless and fiber connections seamlessly, so that it can support the offloading transmission with low delay and wide bandwidth. Based on the ONER scheme supported by FiWi networks, computation tasks can be offloaded to edge computing nodes in a wider range of area without increasing wireless hops (e.g., just one wireless hop), which achieves low delay. Additionally, an efficient Computation Resource Scheduling (CRS) algorithm based on the ONER scheme is also proposed to make offloading decision. The results show that more offloading requests can be satisfied and the average completion time of computation tasks decreases significantly with the ONER scheme and the CRS algorithm. Therefore, the ONER scheme and the CRS algorithm can schedule computation resources at neighboring edge computing nodes for offloading to meet the challenge of large scale computation tasks.

A Tunable Optical Delay Line Based on Cascaded Silicon Nitride Microrings for Ka-Band Beamforming

A continuously tunable optical delay line with low delay ripple based on four cascaded tunable silicon nitride microring resonators for Ka-band beamforming network is proposed. The delay responses of the tunable optical delay line were investigated theoretically and experimentally. And a maximum delay tuning range of 300.3 ps, 169.4 ps and 88.6 ps were achieved when the delay bandwidth is set as 2 GHz, 5 GHz and 10 GHz respectively. In addition, low delay ripple about 8.5 ps and low additional loss less than 3.6 dB were obtained. Moreover, the maximum delay tuning range was increased to about 395 ps by combining the off-resonance region of the cascaded MRRs.

Quantum networks for single photon detection

Single photon detection generally consists of several stages: the photon has to interact with one or more charged particles, its excitation energy will be converted into other forms of energy, and amplification to a macroscopic signal must occur, thus leading to a "click." We focus here on the part of the detection process before amplification (which we have studied in a separate publication). We discuss how networks consisting of coupled discrete quantum states and structured continua (e.g. band gaps) provide generic models for that first part of the detection process. The input to the network is a continuum (the continuum of single-photon states), the output is again a continuum describing the next irreversible step. The process of a single photon entering the network, its energy propagating through that network and finally exiting into another output continuum of modes can be described by a single dimensionless complex transmission amplitude, $T(\omega)$. We discuss how to obtain from $T(\omega)$ the photo detection efficiency, how to find sets of parameters that maximize this efficiency, as well as expressions for other input-independent quantities such as the frequency-dependent group delay and spectral bandwidth. We then study a variety of networks and discuss how to engineer different transmission functions $T(\omega)$ amenable to photo detection.

Improving Cloud Gaming Experience through Mobile Edge Computing

With the development of 4G/5G technology and smart devices, more and more users begin to play games via their mobile devices. As a promising way to enable users to play any games, cloud gaming is proposed to stream game scene rendered remotely in the cloud with the format of video. However, it faces major challenges in terms of long delay and high network bandwidth. To this end, a novel framework named EdgeGame is proposed to improve the cloud gaming experience by leveraging resources in the edge. Compared to existing cloud gaming systems, EdgeGame offloads the computation-intensive rendering to the network edge instead, which can reduce network delay and bandwidth consumption greatly. Moreover, EdgeGame introduces deep reinforcement learning in the edge to adjust the video bitrates adaptively to accommodate the network dynamics. Finally, we implemented a prototype system and compared it with an existing cloud gaming system. The experiments show that EdgeGame can reduce the average network delay by 50 percent and improve user's QoE by 20 percent.

Design of EPICS and Web-Based Remote Control Software of Near-Infrared Sky Brightness Monitor in Antarctica

The Near-infrared Sky Brightness Monitor (NIRBM) aims to measure the middle infrared sky background in Antarctica. The NIRBM mainly consists of an InGaAs detector, a chopper, a reflector, a cooler and a black body. The reflector can rotate to scan the sky with a field of view ranging from 0{\deg} to 180{\deg}. Electromechanical control and weak signal readout functions are accomplished by the same circuit, whose core chip is a STM32F407VG microcontroller. Considering the environment is harsh for humans in Antarctica, a multi-level remote control software system is designed and implemented. A set of EPICS IOCs are developed to control each hardware module independently via serial port communication with the STM32 microcontroller. The tornado web framework and PyEpics are introduced as a combination where PyEpics is used to monitor or change the EPICS Process Variables, functioning as a client for the EPICS framework. Tornado is responsible for the specific operation process of inter-device collaboration, and expose a set of interfaces to users to make calls. Considering the high delay and low bandwidth of the network environment, the tornado back-end is designed as a master-and-agent architecture to improve domestic user experience. The master node is deployed in Antarctic while multiple agent nodes can be deployed domestic. The master and agent nodes communicate with each other through the WebSocket protocol to exchange latest information so that bandwidth is saved. The GUI is implemented in the form of single-page application based on the Vue framework which communicates with tornado through WebSocket and AJAX requests. The web page integrates device control, data curve drawing, alarm display, auto observation and other functions together.

Proposal of cross‐layer bandwidth assignment with buffer size indication for TCP flow control

AbstractIn this paper, we propose, verify, and evaluate a method combining cross‐layer method and bandwidth allocation to overcome the difficulty of flow control in a network with large bandwidth delay product. When the bandwidth delay product is large, there are problems with the convergence time, efficiency and stability of bandwidth utilization, and fairness among traffics of different round‐trip time. As a result of examining the conventional methods, we propose a novel method that can be realized as a functional addition to the existing transmission control protocol (TCP) flow control with improvement in utilization efficiency, fairness, stability, and convergence time. The method is compared with TCP Reno, FAST TCP, CUBIC, Explicit Congestion Notification, and eXplicit Control Protocol by simulation, and is confirmed as having good characteristics.