Real-time Quality Of Service Research Articles

Research on Holographic Evaluation of Service Quality in Power Data Network

With the rapid development of power data network, the continuous development of the Power data application service system, more and more service systems are being put into operation. Following this, the higher requirements for network quality and service quality are raised, in the actual process for the network operation and maintenance. This paper describes the electricity network and data network services status. A holographic assessment model was presented to achieve a comprehensive intelligence assessment on the power data network and quality of service in the operation and maintenance on the power data network. This evaluation method avoids the problems caused by traditional means which performs a single assessment of network performance quality. This intelligent Evaluation method can improve the efficiency of network operation and maintenance guarantee the quality of real-time service in the power data network..

Online QoS Prediction for Runtime Service Adaptation via Adaptive Matrix Factorization

Cloud applications built on service-oriented architectures generally integrate a number of component services to fulfill certain application logic. The changing cloud environment highlights the need for these applications to keep resilient against QoS variations of their component services so that end-to-end quality-of-service (QoS) can be guaranteed. Runtime service adaptation is a key technique to achieve this goal. To support timely and accurate adaptation decisions, effective and efficient QoS prediction is needed to obtain real-time QoS information of component services. However, current research has focused mostly on QoS prediction of working services that are being used by a cloud application, but little on predicting QoS values of candidate services that are equally important in determining optimal adaptation actions. In this paper, we propose an adaptive matrix factorization (namely AMF) approach to perform online QoS prediction for candidate services. AMF is inspired from the widely-used collaborative filtering techniques in recommender systems, but significantly extends the conventional matrix factorization model with new techniques of data transformation, online learning, and adaptive weights. Comprehensive experiments, as well as a case study, have been conducted based on a real-world QoS dataset of Web services (with over 40 million QoS records). The evaluation results demonstrate AMF's superiority in achieving accuracy, efficiency, and robustness, which are essential to enable optimal runtime service adaptation.

Function Split Between Delay-Constrained Routing and Resource Allocation for Centrally Managed QoS in Industrial Networks

Industrial networks demand centrally controlled quality of service (QoS), often in the form of hard real-time guarantees. Software-defined networking (SDN) provides a convenient paradigm for central QoS control. However, existing SDN-based solutions cannot guarantee hard real-time QoS as they rely on a control loop over the forwarding (data) and control planes. We propose a novel SDN-based QoS control framework that maintains an accurate network model through network calculus to avoid a control loop over forwarding and control planes, allocates resources to and routes flows over a network of “queue links,” whereby each physical network link houses multiple queue links (with different QoS levels), and manages QoS through a function split between delay-constrained least-cost routing on the network of queue links and the resource allocation to the queue links. This function split greatly reduces the computational complexity while achieving hard real-time QoS with high bandwidth utilization. Our evaluation results indicate that our function split approach allows for online runtime admission control and can achieve bandwidth utilization above 80% while meeting deterministic real-time QoS requirements.

On The Verification and Realization of VANET Applications

Modeling and realization of Vehicular Ad-Hoc Network (VANET) applications and protocols are very challenging; due to VANET`s unique mobility, driver behavior, signaling and road topology requirements. Although network simulators are commonly used to evaluate wireless network per-formance, VANET applications require mobility simulators to mimic road traffic topology and mobility. However, network and mobility simulators fall short of evaluating Quality of Experience (QoE) and Quality of Service (QoS) of context-rich applications with multiple user interactions. Using real hardware provides a solid mechanism to evaluate QoE and QoS in real time, though it is very expensive to use in large networks and difficult to reproduce specific VANET scenarios such as collisions and signaling changes due to speed and road topology. Emulation techniques combine the benefits of using both simulation and hardware approaches. Recently, multiple Ad-Hoc emulators have been developed, but they are not tailored to VANET`s requirements. In this article, the most suitable network and mobility simulators and their integrations for VANET are surveyed. Subsequently, their features, popularity and challenges are compared, the best ones corresponding to VANET application conditions are rec-ommended. Moreover, a comprehensive review is performed on Ad-Hoc emulators showing the benefits and suitability of each one for VANET applications. This article serves as a starting point for the development of comprehensive VANET emulators and testbeds; it also acts as a start-up guide for researchers to select the best tools for VANET application, protocol modeling, simulation, and emulation. Keywords: Vehicular Ad-Hoc Networks (VANET), Wireless Network Simulation, Mobility Simulation, Network Emulation, Performance Analysis.

Enhancing the Quality of Service for Real Time Traffic over Optical Burst Switching (OBS) Networks with Ensuring the Fairness for Other Traffics.

Optical burst switching (OBS) networks have been attracting much consideration as a promising approach to build the next generation optical Internet. A solution for enhancing the Quality of Service (QoS) for high priority real time traffic over OBS with the fairness among the traffic types is absent in current OBS’ QoS schemes. In this paper we present a novel Real Time Quality of Service with Fairness Ratio (RT-QoSFR) scheme that can adapt the burst assembly parameters according to the traffic QoS needs in order to enhance the real time traffic QoS requirements and to ensure the fairness for other traffic. The results show that RT-QoSFR scheme is able to fulfill the real time traffic requirements (end to end delay, and loss rate) ensuring the fairness for other traffics under various conditions such as the type of real time traffic and traffic load. RT-QoSFR can guarantee that the delay of the real time traffic packets does not exceed the maximum packets transfer delay value. Furthermore, it can reduce the real time traffic packets loss, at the same time guarantee the fairness for non real time traffic packets by determining the ratio of real time traffic inside the burst to be 50–60%, 30–40%, and 10–20% for high, normal, and low traffic loads respectively.

Probabilistic QoS Aggregations for Service Composition

In this article, we propose a comprehensive approach for Quality of Service (QoS) calculation in service composition. Differing from the existing work on QoS aggregations that represent QoS as single values, discrete values with frequencies, or standard statistical distributions, the proposed approach has the capability to handle any type of QoS probability distribution. A set of formulae and algorithms are developed to calculate the QoS of a composite service according to four identified basic patterns as sequential, parallel, conditional, and loop. We demonstrate that the proposed QoS calculation method is much more efficient than existing simulation methods. It has a high scalability and builds a solid foundation for real-time QoS analysis and prediction in service composition. Experiment results are provided to show the effectiveness and efficiency of the proposed method.

Co-operative Traffic Solutions for Hybrid Communication Environments

Through communication between vehicles and infrastructure, vehicles can receive real-time warnings on incidents and dangerous situations, and can send own sensor data and observed incident information to other road users. Information between vehicles and infrastructures can be exchanged either using ITS-G5 or cellular communications. This paper describes how a fog vision sensor has been developed and deployed for warning drivers about adverse road weather conditions. A hardware-in-the-loop driving simulator has been utilized to test the transmission of vehicle data. Performance measurements of the communication between vehicles and infrastructure have been made for both ITS-G5 and LTE. LTE and the future 5G will provide lower latency, and hence may become the preferred solution especially for road side unit to vehicle communications. Providing seamless connectivity between different network technologies, a mobile IP based solution is utilized with Quality-of-Service (QoS) assisted handovers. Real-time QoS measurements with fast handovers enable the system to react rapidly to changing circumstances. Our solution can exploit multiple networks and prioritize them by quantities such as preference, signal strength and geotagged formerly measured link quality.

Real-Time QoS Routing Protocols in Wireless Multimedia Sensor Networks: Study and Analysis.

Many routing protocols have been proposed for wireless sensor networks. These routing protocols are almost always based on energy efficiency. However, recent advances in complementary metal-oxide semiconductor (CMOS) cameras and small microphones have led to the development of Wireless Multimedia Sensor Networks (WMSN) as a class of wireless sensor networks which pose additional challenges. The transmission of imaging and video data needs routing protocols with both energy efficiency and Quality of Service (QoS) characteristics in order to guarantee the efficient use of the sensor nodes and effective access to the collected data. Also, with integration of real time applications in Wireless Senor Networks (WSNs), the use of QoS routing protocols is not only becoming a significant topic, but is also gaining the attention of researchers. In designing an efficient QoS routing protocol, the reliability and guarantee of end-to-end delay are critical events while conserving energy. Thus, considerable research has been focused on designing energy efficient and robust QoS routing protocols. In this paper, we present a state of the art research work based on real-time QoS routing protocols for WMSNs that have already been proposed. This paper categorizes the real-time QoS routing protocols into probabilistic and deterministic protocols. In addition, both categories are classified into soft and hard real time protocols by highlighting the QoS issues including the limitations and features of each protocol. Furthermore, we have compared the performance of mobility-aware query based real-time QoS routing protocols from each category using Network Simulator-2 (NS2). This paper also focuses on the design challenges and future research directions as well as highlights the characteristics of each QoS routing protocol.

Quality of service management for IPTV services support in VANETs: a performance evaluation study

In order to deliver a qualitative Internet Protocol Television (IPTV) service over vehicular ad hoc networks (VANETs), a quality of service (QoS) mechanism is needed to manage the allocate of network resources to the diverse IPTV application traffic demands. Unlike other mobile network, VANETs have certain unique characteristic that presents several difficulties in providing an effective QoS. Similarly, IPTV requires a constant stream for QoS which at the moment is quite difficult due to the inherent VANET characteristics. To provide an effective QoS that will meet the IPTV application service demands, VANETs, must satisfy the compelling real-time traffic streaming QoS requirement (i.e., minimum bandwidth allocation, packet loss and jitter). In this report, we evaluate via simulation the feasibility of deploying quality IPTV services over VANETs, by characterizing the association between the IPTV streaming quality determining factors (i.e., throughput, delay, loss, jitter) and the IPTV quality degradation, with respect to node density and node velocity. Furthermore, we used an objective QoS metric (Media-Delivery-Index) to identify, locate and address the loss or out-of-order packet. We outline how, using these information's can support in shaping network parameters to optimize service flows. The implementation assures a priority for handling IPTV traffic, such that maximise the usage of VANETs resources, and opens the possibility that loss and delay can be minimised to a degree that could guarantee quality IPTV service delivery among vehicle in a vehicular network system.

Real-Time Traffic-Differentiated QoS Routing for Wireless Sensor Networks

Wireless sensor networks (WSNs) emerge as underlying infrastructures for new classes of large scale networked embedded systems. However, WSNs system designers must fulfill the Qualityof-Service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments and extremely limited resources are major obstacles for satisfying QoS metrics such as reliability, timeliness, and system lifetime. The limited communication range of WSN nodes, link asymmetry, and the characteristics of the physical environment lead to a major source of QoS degradation in WSNs. This paper proposes a Real-Time Traffic-Differentiated Routing protocol for Wireless Sensor Networks (WSNs). It targets WSN applications having different types of data traffic with several priorities. The protocol achieves to increase packet reception ratio and reduce end-to-end delay while considering multi-queue priority policy, two-hop neighborhood information, link reliability and power efficiency. The protocol is modular and utilizes memory and computational effective methods for estimating the link metrics. Numerical results show that the proposed protocol is a feasible solution to addresses QoS service differentiation for traffic with different priorities.

Shipboard Power Systems Reconfiguration—A Cyber-Physical Framework For Response Time Analysis

Several applications within a shipboard system involve the integration of physical systems (e.g., power systems) and cyber computing platforms such as command and control, communications, and sensing networks, and require real-time quality of service (QoS) guarantees. In this paper, the distribution of total (end-to-end) delay associated with fault diagnosis and reconfiguration of shipboard power system (SPS) is investigated from a cyber-physical systems (CPS) perspective. Specifically, a cross-layer end-to-end delay analysis framework is introduced for SPS reconfiguration. The proposed framework stochastically models the heterogeneity of actions of various subsystems involved in the reconfiguration tasks viz., generation of fault information by sensor nodes associated to the power system, processing of actions at control center to resolve fault locations and reconfiguration, and flow of information through communication network to perform necessary actions. The proposed framework then combines appropriately the output delay distributions from each subsystem to: 1) analytically predict the distribution of end-to-end delay in SPS reconfiguration after the occurrence of faults and 2) analyze and design real-time reconfiguration solutions for shipboard CPS, that meet total delay requirements. Simulations using various topological scenarios demonstrate that the proposed analytical framework closely predict the total delay associated with SPS reconfiguration.

Packet Scheduling Algorithm Considering Maximum Delay Tolerance for HSDPA System

In this paper, we consider a new packet scheduling algorithm for real-time traffic in the HSDPA system that has been introduced for the WCDMA system, in order to provide high transmission rates. The objective of the design is to meet the maximum tolerable delay and consider channel assignment based on the received SIR for real-time traffic users. The proposed scheduling algorithm shows that the users are ranked by the ratios of the bits in the buffer to the residual time for transmission as priority order; then the ranked users are assigned certain number of channels based on the SIR value table. The simulation results show that the proposed algorithm can provide a lower packet drop rate, and satisfy real time quality of service (QoS) requirements.

Distributed multi-hop reservation protocol for wireless personal area Ultra-Wideband networks

Ultra-wideband (UWB) technology is a promising technology for multimedia applications in wireless personal area networks (WPANs) that supports very high data rates with lower power transmission for short range communication. The limitation of coverage radius of UWB network necessitates for multihop transmissions. Unfortunately, as the number of hops increases, the quality of service (QoS) degrades rapidly in multihop network. The main goal of this research is to develop and enhance multihop transmission that ensures QoS of real time traffic through the proposed distributed multihop reservation (DMR) scheme. The DMR scheme consists of two modules; distributed multihop reservation protocol (DMRP) and path selection. DMRP incorporates resource reservation, routing and connection setup that are extended on the existing WiMedia Media Access Control protocol (MAC). On the other hand, the path selection determines the optimal path that makes up the multihop route. The path selection selects nodes based on the highest Signal to Interference and Noise Ratio (SINR). The performance of DMR scheme has been verified based on the performance of the video traffic transmission. The main metrics of QoS are measured in terms of Peak Signal- to- Noise ratio (PSNR), End-to-End (E2E) delay, and throughput. The results show that DMRP compared to Multiple Resources Reservation Scheme (MRRS) in six (6) hops transmission has enhanced the average PSNR by 16.5%, reduced the average E2E delay by 14.9% and has increased the throughput by 11.1%. The DMR scheme which is the inclusion of path selection in DMRP has been compared to Link Quality Multihop Relay (LQMR). DMR scheme has improved the video quality transmission by 17.5%, reduced the average E2E delay by 18.6% and enhanced the average throughput by 20.3%. The QoS of six (6) hops transmission employing DMR scheme is almost sustained compared to two hops transmission with the QoS experiencing only slight degradation of about 2.0%. This is a considerable achievement as it is well known that as the number of hops increases the QoS in multihop transmission degrades very rapidly. Thus DMR scheme has shown to significantly improve the performance of real time traffic on UWB multihop network. In general, DMR can be applied to any WPAN network that exploit multihop transmission.

Reservation Conflict-Free MAC Design for Mobile Wireless USB Devices with Distributed MAC

In this paper, a collision-free resource reservation scheme for WUSB (Wireless Universal Serial Bus) networks with WiMedia D-MAC (Distributed Medium Access Control), Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WUSB with WiMedia D-MAC can be deteriorated. In addition, when we consider multi-hop environment, “mobile” hidden node problem due to mobility of WUSB devices can be happened, and it is a critical problem to mobile WUSB devices transceiving real-time QoS(Quality of Service) traffic. To tackle the problem, we propose a new DRP reservation mechanism to prevent DRP conflicts for multi-hop mobility support in WUSB networks with WiMedia D-MAC and show its improved performance via simulation results.

Analysing Real Time Communications on DDS over FlexRay

In this paper we present an approach to timing analysis of applications communicating over a FlexRay bus, taking into consideration the specific aspects of the publish subscribe paradigm. We give an overview of works dealing with Data Distribution Service (DDS), scheduling over FlexRay and scheduling over the Control area Network (CAN). We are interesting in real time Quality of Service (QoS) for DDS. We specially focus on real time communication on static and dynamic FlexRay bus. We give our approach to calculate deadline on a DDS distribution using the equal Flexibility. We give also DDS and the task models for the computation.

Analyzing Real Time Communication Over FlexRay

In this paper we present an approach to timing analysis of applications communicating over a FlexRay bus, taking into consideration the specific aspects of the publish subscribe paradigm. We give an overview of works dealing with Data Distribution Service (DDS), scheduling over FlexRay and scheduling over the Control area Network (CAN). We are interesting in real time Quality of Service (QoS) for DDS. We specially focus on real time communication on static and dynamic FlexRay bus. We give our approach to calculate deadline on a DDS distribution using the equal Flexibility. We give also DDS and the task models for the computation. In Many distributed embedded real-time applications, like military, automobile, aeronautique data produced in one component of the system needs to be shared with other components of the system. The middleware Data Distribution Service DDS is divided into two components: the Data-Centric Publish-Subscribe DCPS layerand the Data local Reconstruction Layer DLRL. The DCPS layer transports data from publishers to subscribers according to Quality of Service QoS constraints associated with the data topic, publisher, and subscriber. The DLRL allows distributed data to be shared by local objects located remotely from each other as if the data is local. The DLRL is built on top of the DCPS layer. DDS impose of Service in transmission between publishers and subscribers. The transmission of data is managed by the real time bus. Real time applications use CAN or FlexRay bus. The challenge is to deal with a configuration using DDS middleware over FlexRay bus. The goal of using QoS in DDS is that all DataReaders read temporally valid data. DDS proveides QosPolicies specifically targeted to minimum latency, predictable real-time operation in high performance distributed data-critical systems. The DEADLINE QosPolicy expresses the maximum duration within which a DataReader expects a data-object instance to be updated. Our research team was interested in the LifeSpan (LS) Qos which concerns the Topic and the Data Writer entities. It specifies the maximum duration of validity of the data written by the DataWriter. They developed [6] an algorithm that calculate data distribution deadline. The following assumptions are considered: all nodes, data objects, and scheduling parameters are known a priori; each DataReader/DataWriter has a local node, where it originates.; the period of a DataWriter is always less than its Lifespan; and the offered deadline period is always less then the requested deadline period. This work gives an analysis for deadline computation on a FlexRay bus. The goal is to consider the data-centric publish- subscribe (DCPS) and to use DDS Qos. Both Dynamic segment and static segment are considered. We are currently working on a project to implement deadline computation with C language in order to finalize our works dealing with our DDS implementation.

Modelling and performance evaluation of the IEEE 802.11 DCF for real-time control

Popular wireless networks, such as IEEE 802.11/15/16, are not designed for real-time applications. Thus, supporting real-time quality of service (QoS) in wireless real-time control is challenging. This paper adopts the widely used IEEE 802.11, with the focus on its distributed coordination function (DCF), for soft-real-time control systems. The concept of the critical real-time traffic condition is introduced to characterize the marginal satisfaction of real-time requirements. Then, mathematical models are developed to describe the dynamics of DCF based real-time control networks with periodic traffic, a unique feature of control systems. Performance indices such as throughput and packet delay are evaluated using the developed models, particularly under the critical real-time traffic condition. Finally, the proposed modelling is applied to traffic rate control for cross-layer networked control system design.

A Switched System Approach to Exponential Stabilization Through Communication Network

This paper considers a networked control loop, where the plant is a “slave” part, and the remote controller and observer constitute the “master”. Since the performance of networked control systems (NCS) depends on the quality of service (QoS) available from the network, it is worth to design a controller that takes into account qualitative information on the QoS in realtime. The goal of the design is to provide a controller that guarantees the following two things: 1) high performances (here expressed by exponential decay rates) when the QoS remains globally the same and 2) global stability when the QoS changes. In order to guarantee the global stability, the controller will switch by respecting a dwell time constraint. The dwell time parameters are obtained by using the switched system theories and the obtained conditions are linear matrix inequalities. An experiment illustrates how the controller can be implemented for a control over Internet application (remote control of a small robot).

QoS Analysis in IMS Network

Fixed-mobile networks convergence and multimedia services supply at any device and any access are enabled in IMS technology. It is a network and layered architecture using packet transmission in the transport layer. For IMS interoperability with different technology networks, there are network gateways, which affects the quality of real-time services. Qualitative analysis of the service flows is carried out in this work. Also there is evaluating fixed access specification and packets service distributions. The delay dependence on utilization rate in the system also on service time dispersion there is assessing in this work. Ill. 5, bibl. 9, tabl. 1 (in English; abstracts in English and Lithuanian). http://dx.doi.org/10.5755/j01.eee.112.6.442

IPTV 서비스 품질의 사전 관리를 위한 서비스 이용자 중심의 상시 측정 방안 구현과 검증

최근 네트워크의 광대역화에 따라 새로 등장한 대표적인 서비스로 IPTV(Internet Protocol Television) 서비스를 들 수 있다. 서비스 품질(Quality of Service; QoS)이 보장되지 못하는 인터넷을 통한 IPTV 서비스가 성공적으로 정착하여 활성화되기 위해서는 철저한 서비스 품질 관리가 필수적이다. 이를 위해서는 기존의 계측기에 의한 서비스 품질의 사후 관리는 향후 서비스 이용자가 서비스를 받는 중 이루어지는 실시간 측정 위주의 서비스 품질 관리로 바뀌어야 할 필요가 있다. 따라서 본 논문에서는 서비스 이용자 위주의 상시 품질 측정이 가능한 IPTV 서비스 품질 관리 방안을 제안한다. 제안된 방안의 구현을 위해 개발된 소프트웨어는 서비스 이용자 측의 셋톱박스에 설치되어 실시간으로 IPTV 서비스의 품질을 상시 측정하고 이를 보고할 수 있는 기능을 갖추고 있다. 구현된 소프트웨어의 신뢰성을 검증하기 위하여 다수 개의 중요 지표들에 대해서 대표적인 두 개의 상용 계측기와 비교하였고 그 결과 개발된 소프트웨어를 통한 측정 결과가 사용 계측기와 크게 다르지 않고 신뢰할 수 있음을 보였다. Recently internet protocol television (IPTV) service is becoming a typical emerging service enabled on broadband networks. Through the Internet which cannot support quality of service (QoS) beyond best-effort (BE) policy, how to manage and maintain its service quality is an important and essential issue for successful deployment and settlement of IPTV service. In particular, the current measurement scheme that mostly depends on specific equipments should be replaced with one that supports realtime and constant measurement achieved on a user's own will. Therefore, this paper proposes a scheme so-called 'user centric realtime measurement' of IPTV service. The developed software, which is installed in a set-top box (STB) at a user's premise, measures and reports the quality of IPTV service in realtime. In order to verify the performance and accuracy of the developed software, a number of tests are performed comparing to the measurement values from two major measurement equipments. The result of the tests shows that the measurement by the implemented software is significantly reliable.