IMS Network Research Articles

Effects of On-Site Weather Conditions on the Detection Capability of the Infrasound Station of Madagascar I33MG

Noise due to surface wind and temperature is a problem in infrasound. Efficiency of IMS network concerns scientists. It is obvious to find the causes of deficiencies of detection of infrasound station by studying background noise power with respect to the surface wind and the temperature. Data measured by MB2000 microbarometer of infrasound station I33MG are used for the study. Infrasound records are separated into 4 frequency bands centered respectively at: 1 Hz, 0.25 Hz, 0.0625 Hz and 0.0156 Hz. Effects of surface wind and temperature are studied by plotting the variations of the background noise power with respect to the temperature or wind speed in the four considered frequency bands and compared with the median of background noise power. The influence of temperature is manifested by a reduction in the number of low-frequency detection. The surface wind reduces the number of detection at a high frequency. An exponential function is proposed to predict the variations of the noise power in different observation frequencies and temperature and wind conditions. The views expressed herein are those of the authors and do not necessarily reflect the views of the CTBTO Preparatory Commission.

A proposed Estimation for High Performance Level of VVoIP System on a live Service IMS Network

A proposed Estimation for High Performance Level of VVoIP System on a live Service IMS Network

Fault Diagnosis Knowledge Reasoning of Switching Network in Distributed Generation Based on Petri Net

Telephone network based on IMS technology has been widely applied inpower production and dispatching communication, especially in distributedpower stations. Analysis and positioning failure of IMS network is arduous,because it’s dependent on IP data communication network. In this paper,we first introduced IMS switching network architecture and distributed gen-eration communication network architecture, analyzed and summarized allkinds of network malfunction. Combining typical IMS network fault con-nection relations, we introduced an improved Petri net fault handling modeland reasoning method. The diagnosis and positioning results could reflectthe defects of equipment logic functions. This method on fault diagnosisand location of substation network has been proved to be effective throughpractical application.

Fast update method of new equipment status in IMS network based on ant colony optimization algorithm

In order to update the status of new equipments in IMS network quickly, a new method based on ant colony optimization algorithm is studied. This method is to lock the new status of IMS network and establish the location model of new equipment in IMS network. For the new equipment in IMS network that has been located, the load balancing method of new equipment in IMS network based on ant colony optimization algorithm is adopted to obtain the optimal operation state of new equipment in IMS network, and realize the rapid update of new equipment status in IMS network. The experimental results show that: the proposed method can accurately locate the coordinates of new equipments in IMS network when the node regularity is significant or not; it can effectively improve the update speed of new equipments in IMS network, and realize the rapid update of new equipment status in IMS network; the negative impact on IMS network is smaller, and under the premise of small and large load of IMS network, the proposed method can improve the performance of IMS network. When the new IMS network adds new equipment status, the false alarm rate is small and the update result is reliable.

Analysis of Hydroacoustic Signals Associated to the Loss of the Argentinian ARA San Juan Submarine

On November 15, 2017, an event related to the disappearance of the Argentine military submarine ARA San Juan was detected by two hydrophone triplet stations of the IMS network, established to enforce the nuclear test ban treaty (CTBT). From the two direct hydroacoustic arrivals recorded at 6000 and 8000 km from the localized wreckage, calculated location based on hydroacoustic data only is poorly constrained, and the associated uncertainties are large. In an attempt to interpret the recorded signals, an air dropped calibration grenade was conducted by the Argentine Navy two weeks later, on December 1, 2017, near the last known position of the submarine. From the comparison of temporal and spectral features of both events, we confirm the impulsive nature of the San Juan event. Array processing was performed with a progressive multi-channel correlation method (PMCC). Fine propagation details of direct arrivals are very well resolved in time-frequency space and thirteen secondary arrivals are revealed for the San Juan event, within the fifteen minutes following direct arrivals. The detections presented in this paper were calculated with DTK-PMCC software embedded in the NDC-In-A-Box virtual machine, and can be reproduced by any CTBTO principal user (Member State user which can access raw waveform data and data bulletins). All the identified late arrivals are associated to reflections or refractions from seamounts, islands and the South American continental Slope. The accurate identification of all the reflectors allows to significantly improve the source location accuracy: 95% confidence ellipse area has been reduced by a factor of 100 compared to location obtained from direct arrivals only, and the estimated location is 3.5 km from the known location of the wreckage. The originality of the relocation method is that it is based on the joint inversion of both San Juan and calibration events unknown parameters, and from the selection of only a well-chosen subset of secondary arrivals. Its calculation did not require either the need of advanced oceanographic specifications, or sophisticated methods requiring heavy computational means. Finally, a detailed cepstral analysis of the direct and secondary arrivals has allowed to detect the existence of a second impulse (doublet) in the signals associated to both San Juan and calibration events. Unlike the calibration event, the anisotropic character of the delays measured from the San Juan cepstra suggests that the 15 November signal was generated by two impulsive acoustic sources closely separated in space and time over scales comparable to the size of the submarine. This study demonstrates the capability of the hydroacoustic component of the IMS network to accomplish its mission of Comprehensive Nuclear-Test-Ban Treaty monitoring.

BazNet: A Deep Neural Network for Confident Three-component Backazimuth Prediction

As the Treaty Monitoring Community seeks to lower detection thresholds across its sparse sensor network, single-station location estimates and accurate backazimuth predictions become increasingly important. Accurate backazimuth predictions are traditionally limited to array stations, where beamforming provides high-confidence backazimuth prediction that can be reliably passed on to the associator. Three-component stations, on the other hand, rely on polarization analysis for backazimuth prediction, which suffers from both high error and low confidence. As such, very few three-component backazimuth predictions are passed on to the association algorithm. This study presents BazNet, a deep neural-network that takes in a three-component seismogram and produces both a backazimuth prediction and corresponding certainty measure. For existing stations with ample historical training data, the technique achieves an overall median absolute deviation of around $$14^{\circ }$$ , a modest improvement over the $$15^{\circ }$$ achieved by polarization. More importantly, each estimate is accompanied by a robust certainty measure, allowing the selection of high-confidence predictions to be passed on to the associator. Using the BazNet certainty measure, roughly 60% of all three-component predictions can be selected with a median absolute deviation of just $$6^{\circ }$$ , which is on par with the predictions from a full beamformed seismic array. This represents a sevenfold improvement over the 8% of signals similarly selectable via polarization analysis. BazNet performance is demonstrated against 10 years of waveform data from 561,154 cataloged arrivals across nine stations selected from the global IMS Network: STKA, CPUP, VNDA, LPAZ, AAK, BOSA, ULM, BATI, INK.

Assessing critical load exceedances and ecosystem impacts of anthropogenic nitrogen and sulphur deposition at unmanaged forested catchments in Europe

Anthropogenic emissions of nitrogen (N) and sulphur (S) compounds and their long-range transport have caused widespread negative impacts on different ecosystems. Critical loads (CLs) are deposition thresholds used to describe the sensitivity of ecosystems to atmospheric deposition. The CL methodology has been a key science-based tool for assessing the environmental consequences of air pollution. We computed CLs for eutrophication and acidification using a European long-term dataset of intensively studied forested ecosystem sites (n = 17) in northern and central Europe. The sites belong to the ICP IM and eLTER networks. The link between the site-specific calculations and time-series of CL exceedances and measured site data was evaluated using long-term measurements (1990–2017) for bulk deposition, throughfall and runoff water chemistry. Novel techniques for presenting exceedances of CLs and their temporal development were also developed. Concentrations and fluxes of sulphate, total inorganic nitrogen (TIN) and acidity in deposition substantially decreased at the sites. Decreases in S deposition resulted in statistically significant decreased concentrations and fluxes of sulphate in runoff and decreasing trends of TIN in runoff were more common than increasing trends. The temporal developments of the exceedance of the CLs indicated the more effective reductions of S deposition compared to N at the sites. There was a relation between calculated exceedance of the CLs and measured runoff water concentrations and fluxes, and most sites with higher CL exceedances showed larger decreases in both TIN and H+ concentrations and fluxes. Sites with higher cumulative exceedance of eutrophication CLs (averaged over 3 and 30 years) generally showed higher TIN concentrations in runoff. The results provided evidence on the link between CL exceedances and empirical impacts, increasing confidence in the methodology used for the European-scale CL calculations. The results also confirm that emission abatement actions are having their intended effects on CL exceedances and ecosystem impacts.

A Simulator for Reporting Performance Data from Network Element To Network Management System

Now a days, the biggest challenge for Mobile Network Operators is to provide broadband service with high performance.4G(VoLTE) has been developed to meet user requirement by offering high speed data transfer services using IMS network. The key performance indicators (KPI) are used to monitor and optimize mobile network performance in order to provide high quality services using counters. The indicators are standardized by third-generation partnership project(3GPP). Simulators are used in network element so that we can check the capacity of each VM and calculated using counters from element management system to network management system.

THE INVESTIGATION AND EVALUATION MULTISERVICE NETWORK NGN/IMS FOR MULTIMEDIA TRAFFIC

Òhe functional architecture of the subsystem picture messaging-IMS (Internet Protocol Multimedia Subsystem) for multimedia session management for multiservice NGN/IMS networks that determine the interaction systems and NGN protocols are investigated. The basic element of the IMS core network architecture are session control function CSCF (Call/Session Control Function) which is implemented on the SIP-server (Session Initiation Protocol) using the protocol. A block diagram of the functioning of the traffic service model of multimedia services in the NGN/IMS network when establishing sessions that use the network elements of the user data server HSS (Home Subscriber Server), CSCF control system core, signaling and media gateways (SGW & MGW, Signaling Gateway & Media Gateway). The characteristics of the effectiveness of the IMS and found that in the NGN / IMS multimedia services network in real time significantly alter the traffic characteristics as a service, and efficiency, which requires new models and approaches to assess the main indicators of quality of the service Triple Play. Based on the analysis of the quality NGN/IMS networks in the provision multimedia services, the mathematical model for evaluating the quality of services. This model takes into account the properties of self-similar random process with Hurst index and describes the quality of functioning of NGN/IMS architectural concept. Based on the model studied when performing voice services with the ability to activate multimedia applications, video telephony, multimedia traffic, Triple Play services. According to the study of mathematical models of NGN / IMS networks using SIP-servers analytical expressions to assess the indicators of a common set of operating characteristics of IP-based networks, which take into account the recommendations of ITU-T Y.1540 and Y.2000 and determined the average waiting time in the queue IMS system in the provision of multimedia services with the required parameters, providing a guaranteed quality of service QoS (Quality of Service). According to the latest recommendations of the ITU-T and based on SMO with queues can be defined by five network characteristics that are indicative of the effectiveness of multi-service NGN/IMS networks and an important indicator of QoS.

Analyse of Measurement Based Admission Control Methods in IMS Networks and Simulation Principle

This paper deals with the quality of service in IP Multimedia Subsystem networks. The evaluation of Quality o Service (QoS) is done through admission control methods. We analyse various methods, which are based on the traffic measurement. The approach that can be applied in finding the suitable admission control method while considering selected QoS parameters is described. Different important QoS parameters can be defined, however we decided to focus on the loss parameter. In our simulations we have used Simple Sum method. Based on the simulation results, we have used new algorithm. The main difference is that it uses the mechanism of time window for achieving more accurate traffic estimate. Algorithm Measured Sum with implementation of time window T has better ability to predict the traffic fluctuation. Compared to the Simple Sum algorithm it achieves lower link utilisation, but also lower level of loss ratio.

Bases for the construction of a QoS model for a video-calls service in a virtualized IMS network

Package-based services are affected by different network parameters and conditions that can deteriorate the quality of the transmitted services, especially those that are provided in real time. In this paper, result of an undergraduate research project, the bases for the construction of a QoS model are defined for a video call on an IMS network, specifying the most adequate parameters to estimate its QoS, the infrastructure used, and the tests developed. The results indicate the possibility of improving the QoS by applying the horizontal scaling technique over the IMS Core of the network since, in the vertical scalability, no major improvements were observed when increasing the physical resources of the virtual machines where the Core IMS was installed. Also, the bandwidth that complies the conditions of the quality parameters such as packet loss, delay, and jitter, to provide a good quality video call service is 640 kbps.

Traffic Management by Using Admission Control Methods in Multiple Node IMS Network

The paper deals with Admission Control methods (AC) as a possible solution for traffic management in IMS networks (IP Multimedia Subsystem) - from the point of view of an efficient redistribution of the available network resources and keeping the parameters of Quality of Service (QoS). The paper specifically aims at the selection of the most appropriate method for the specific type of traffic and traffic management concept using AC methods on multiple nodes. The potential benefit and disadvantage of the used solution is evaluated.

Admission Control Methods in IMS Networks

In this paper we present admission control methods for IMS network. The task of RACS block is to accept or reject new connection into the network. The main goal of the admission control method is to ensure the Quality of Service not only for new connection but also for already accepted connections. We discuss and compare three admission control algorithms in the paper from the qualitative parameters point of view.

Performance analysis of IMS based LTE and WIMAX integration architectures

In the current networking field many research works are going on regarding the integration of different wireless technologies, with the aim of providing uninterrupted connectivity to the user anywhere, with high data rates due to increased demand. However, the number of objects like smart devices, industrial machines, smart homes, connected by wireless interface is dramatically increasing due to the evolution of cloud computing and internet of things technology. This Paper begins with the challenges involved in such integrations and then explains the role of different couplings and different architectures. This paper also gives further improvement in the LTE and Wimax integration architectures to provide seamless vertical handover and flexible quality of service for supporting voice, video, multimedia services over IP network and mobility management with the help of IMS networks. Evaluation of various parameters like handover delay, cost of signalling, packet loss,, is done and the performance of the interworking architecture is analysed from the simulation results. Finally, it concludes that the cross layer scenario is better than the non cross layer scenario.

Analysis of quality-of-service metrics in IMS networks

A network constructed according to the IMS architecture consists of different modules that sequentially process signaling messages transferred during providing communication services. Delays that occur when processing signaling messages determine the quality of service for subscribers. International recommendations define the quality-of-service metrics, which include not only the mean, but also the 95% quantile. The paper proposes an approach to analyzing the quality-of-service characteristics. It is assumed that IMS-network nodes work as multi-server queues with general service time distribution.

New Infrastructure of NGN and IMS Networks

New Infrastructure of NGN and IMS Networks

Transparent reallocation of control functions in IMS deployments

In this article we present a novel solution to transfer users between IMS network elements. This solution enables a home operator to perform an appropriate redistribution of load among the call session control functions of the IMS, which can be deployed as virtualized network functions or over dedicated machines. This way, the operator is enabled to adequately accommodate the instantaneous load generated by users to the available control resources, which may dynamically be activated or deactivated as necessary, as well as to enhance the resilient operation of the IMS deployment. Additionally, our solution does not require any change to the IMS specifications, and at the same time, the procedures are transparent to the end-user applications running at the IMS terminals. Finally, we describe some results obtained with a proof-ofconcept implementation of the procedures presented in the article in order to show the viability and correctness of our proposal.

Impact of Admission Control Methods to the Traffic Management

The paper deals with Admission control methods (AC) in IMS networks (IP multimedia subsystem) as one of the elements that help ensure QoS (Quality of service). In the paper we are trying to choose the best AC method for selected IMS network node to allow access to the greatest number of users. Of the large number of methods that were tested and considered good we chose two. The paper compares Gaussian approximation method and one of the measurement based method, specifically „Measured Sum“. Both methods estimate effective bandwidth to allow access for the greatest number of users/devices and allow them access to prepaid services or multimedia content.

Towards automated test and validation of SIP solutions

IP networks are currently the major communication infrastructure used by an increasing number of applications and heterogeneous services, including voice services. In this context, the session initiation protocol (SIP) is a signaling protocol widely used for controlling multimedia communication sessions such as voice or video calls over IP networks, thus performing vital functions in an extensive set of public and enterprise solutions. However, the SIP protocol dissemination also entails some challenges, such as the complexity associated with the testing/validation processes of IMS/SIP networks. As a consequence, manual IMS/SIP testing solutions are inherently costly and time consuming tasks, being crucial to develop automated approaches in this specific area. In this perspective, this article presents an experimental approach for automated testing/validation of SIP scenarios in IMS networks. For that purpose, an automation framework is proposed allowing to replicate the configuration of SIP equipment from the production network and submit such equipment to a battery of tests in the testing network. The proposed solution allows to drastically reduce the test and validation times when compared with traditional manual approaches, also allowing to enhance testing reliability and coverage. The automation framework comprises of some freely available tools which are conveniently integrated with other specific modules implemented within the context of this work. In order to illustrate the advantages of the proposed automated framework, a real case study taken from a PT Inovacao customer is presented comparing the time required to perform a manual SIP testing approach with the one time required when using the proposed automated framework. The presented results clearly corroborate the advantages of using the presented framework.

NGN Model for the Mexican Rural Context Applied to the e-México System

This paper presents a network model based on a NGN architecture applied to the Mexican rural context and deployed over the optical fiber backbone of the e-Mexico (now Mexico Conectado) system. The proposed model considers the integration of access networks for GERAN, UTRAN and E-UTRAN users, allowing also the interconnection with circuit switched networks. We use the E model proposed by ITU-T to maintain a minimum level of voice quality R>70. Additionally, we calculate the estimated bandwidth consumption during the seven phases that SIP requires establishing a telephone call on IMS networks. Our model includes the calculation of the most significant NGN parameters, taking into account the use of an optimal codec, a percentage of packet loss and link utilization level, for the conditions of the Mexican rural environment and the e-Mexico (now Mexico Conectado) system infrastructure.