scholarly journals Improving Network Performance of IP PBX Based Telecommunication System

2020 ◽  
Vol 11 (2) ◽  
pp. 101
Author(s):  
Wardi Wardi ◽  
Zulfajri Basri Hasanuddin ◽  
Andani Andani ◽  
Jeffry Jo Salli ◽  
Andi Muhammad Syafaat

IP-PBX based communication has become a human need in the era of technology. Some researchers design a wireless telecommunication system based on IP PBX using Raspberry Pi. The previous researches have small network coverage and problematic on the ability of the system to support multiple concurrent connections. Based on these problems, these research aims are to expand the coverage area and increase the number of concurrent calls. This study used Asterisk FreePBX for the media configuration of the servers. The clients: laptops and smartphone devices used Linkin and Bria softphone. The testing was conducted in terms of voice and video services in the form of signal strength, CPU performance of servers, and network performance parameters such as delay, jitter, and packet loss. The results obtained that the CPU performance of the servers for seven calls simultaneously is around 16.9% compared with previous research, at an average of 45%. Based on ETSI standards, the measurement of network performance parameters when communicating between clients outperform than previous research. The clients can communicate well up to 390 meters.  

2021 ◽  
Vol 13 (3) ◽  
pp. 63
Author(s):  
Maghsoud Morshedi ◽  
Josef Noll

Video conferencing services based on web real-time communication (WebRTC) protocol are growing in popularity among Internet users as multi-platform solutions enabling interactive communication from anywhere, especially during this pandemic era. Meanwhile, Internet service providers (ISPs) have deployed fiber links and customer premises equipment that operate according to recent 802.11ac/ax standards and promise users the ability to establish uninterrupted video conferencing calls with ultra-high-definition video and audio quality. However, the best-effort nature of 802.11 networks and the high variability of wireless medium conditions hinder users experiencing uninterrupted high-quality video conferencing. This paper presents a novel approach to estimate the perceived quality of service (PQoS) of video conferencing using only 802.11-specific network performance parameters collected from Wi-Fi access points (APs) on customer premises. This study produced datasets comprising 802.11-specific network performance parameters collected from off-the-shelf Wi-Fi APs operating at 802.11g/n/ac/ax standards on both 2.4 and 5 GHz frequency bands to train machine learning algorithms. In this way, we achieved classification accuracies of 92–98% in estimating the level of PQoS of video conferencing services on various Wi-Fi networks. To efficiently troubleshoot wireless issues, we further analyzed the machine learning model to correlate features in the model with the root cause of quality degradation. Thus, ISPs can utilize the approach presented in this study to provide predictable and measurable wireless quality by implementing a non-intrusive quality monitoring approach in the form of edge computing that preserves customers’ privacy while reducing the operational costs of monitoring and data analytics.


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 621
Author(s):  
Maghsoud Morshedi ◽  
Josef Noll

Video on demand (VoD) services such as YouTube have generated considerable volumes of Internet traffic in homes and buildings in recent years. While Internet service providers deploy fiber and recent wireless technologies such as 802.11ax to support high bandwidth requirement, the best-effort nature of 802.11 networks and variable wireless medium conditions hinder users from experiencing maximum quality during video streaming. Hence, Internet service providers (ISPs) have an interest in monitoring the perceived quality of service (PQoS) in customer premises in order to avoid customer dissatisfaction and churn. Since existing approaches for estimating PQoS or quality of experience (QoE) requires external measurement of generic network performance parameters, this paper presents a novel approach to estimate the PQoS of video streaming using only 802.11 specific network performance parameters collected from wireless access points. This study produced datasets comprising 802.11n/ac/ax specific network performance parameters labelled with PQoS in the form of mean opinion scores (MOS) to train machine learning algorithms. As a result, we achieved as many as 93–99% classification accuracy in estimating PQoS by monitoring only 802.11 parameters on off-the-shelf Wi-Fi access points. Furthermore, the 802.11 parameters used in the machine learning model were analyzed to identify the cause of quality degradation detected on the Wi-Fi networks. Finally, ISPs can utilize the results of this study to provide predictable and measurable wireless quality by implementing non-intrusive monitoring of customers’ perceived quality. In addition, this approach reduces customers’ privacy concerns while reducing the operational cost of analytics for ISPs.


2021 ◽  
pp. 147592172110332
Author(s):  
Mehrdad Ghyabi ◽  
Hamidreza Nemati ◽  
Ehsan Dehghan-Niri

In this article, the coverage area prediction of piezoelectric sensor network for detecting a specific type of under-surface crack in plate-like structures is addressed. In particular, this article proposes a simplified framework to estimate the coverage of any given sensor network arrangement when a critical defect is known. Based on numerical results from finite element methods (FEM), a simplified framework to estimate coverage area of any given network arrangement is developed. Using such a simplified framework, one can avoid time-consuming procedure of evaluating numerous FEM models in estimating sensor network coverage. Back-scatter fields of partial cracks are estimated using a proposed function, whose parameters are estimated from the results of a limited number of FEM simulations. The proposed function efficiently predicts the back-scattered field of any combination of transmitters and receivers for a given crack geometry. Superposition is used to estimate the coverage area of an arbitrary piezoelectric (e.g., PZT) sensor network. It is shown that the coverage area of a sensor network depends on both sensor network geometry and defect properties (e.g., crack inclination) and it is not necessarily a linear function of the number of sensors. Furthermore, it is shown that the network arrangement has an important effect on the geometry of the coverage area. Experimental results of a network of 14 PZTs in two clusters confirm the accuracy of the method.


2014 ◽  
Vol 602-605 ◽  
pp. 3643-3647
Author(s):  
Li Yan Liu ◽  
Rong Fu ◽  
Yi He ◽  
Ying Qian Zhang

Distributed underwater sensor network coverage is divided into two main categories: deterministic coverage and stochastic coverage. A strategy is put forward to deploy determinate area by using a triangular-grid method. When a coverage ratio is known, the distance between nodes can be adjusted to meet the coverage ratio in the monitored area, and the least number of sensor nodes can be calculated. Also a heuristic method is proposed for stochastic area deployment strategy. It is under the premise that the initial node location randomly deployed is given, using Voronoi diagram, the not easiest monitored path is searched, and the network coverage performance is improved by configuring the new nodes in the path. Finally it is proved that network performance is more improved by the simulation experiments, when one to four nodes are configured in the easiest breach path.


2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Ana Oktaviana ◽  
Doan Perdana ◽  
Ridha Muldina Negara

The increasing needs and demands of diverse services by the users to be able to exchange and obtain information in real time, reliable, and flexible to be one of the problems faced by existing communication technology. WLAN on the IEEE 802.11 standard is one of the wireless technologies that can be the solution of the problem. It has a relatively small area of ??communication that is between 20-70 meters only, only able to serve up to 2007 stations, and has considerable energy consumption, causing some systems contained in the WLAN in IEEE 802.11 standard less work maximally. With these shortcomings, the WLAN on the IEEE 802.11 standard introduces a new task group called IEEE 802.11ah. IEEE 802.11ah is a new WLAN standard working on the 900 MHz frequency spectrum, a 1 kilometer communications coverage area, capable of serving 8192 stations with new AID hierarchies, has lower energy consumption and can increase throughput value by RAW mechanism. This study will make changes to the number of RAW slots in the IEEE 802.11ah to see how they affect the network performance. In this research it is found that the change of RAW slot number influence to network performance, in this case is throughput, average delay, packet delivery ratio and energy consumption.


2020 ◽  
Vol 3 (4) ◽  
pp. 48-57
Author(s):  
Derek McGrath ◽  
Jonathan Matusitz

This paper applies the Human Needs Theory to Uighur terrorism. The theory posits that people become violent when their basic human needs are unfulfilled, denied, or taken away from them. Also referred to as the East Turkestan Islamic Movement (ETIM), Uighur terrorists are a minority group of Muslim extremists in the western Chinese Autonomous Region of Xinjiang. Until the mid-1700s, they were considered a peaceful group, but when they lost their autonomy during the Qing dynasty rule (until 1910), and faced oppression by their new government, they resorted to violence. In this case, the Uighurs’ human need “stolen” by the Chinese was their identity. Not only is the Uighur issue underrepresented in the media; it has also received such negligible attention that most governments and scholars believe that the Autonomous Region of Xinjiang is mostly occupied by terrorists.


Author(s):  
Noor Nateq Alfaisaly ◽  
Suhad Qasim Naeem ◽  
Azhar Hussein Neama

Worldwide interoperability microwave access (WiMAX) is an 802.16 wireless standard that delivers high speed, provides a data rate of 100 Mbps and a coverage area of 50 km. Voice over internet protocol (VoIP) is flexible and offers low-cost telephony for clients over IP. However, there are still many challenges that must be addressed to provide a stable and good quality voice connection over the internet. The performance of various parameters such as multipath channel model and bandwidth over the Star trajectoryWiMAX network were evaluated under a scenario consisting of four cells. Each cell contains one mobile and one base station. Network performance metrics such as throughput and MOS were used to evaluate the best performance of VoIP codecs. Performance was analyzed via OPNET program14.5. The result use of multipath channel model (disable) was better than using the model (ITU pedestrian A). The value of the throughput at 15 dB was approximately 1600 packet/sec, and at -1 dB was its value 1300 packet/se. According to data, the Multipath channel model of the disable type the value of the MOS was better than the ITU Pedestrian A type.


Author(s):  
Amine Berqia ◽  
Mohamed Hanini ◽  
Abdelkrim Haqiq

Packet scheduling and buffer management are the two important functions adopted in networks design to ensure the Quality of Service (QoS) when different types of packets with different needs of quality share the same network resources. The Packet scheduling policy determines packet service priorities at the output link, it can reduce packet delay and delay jitter for high-priority traffic. The buffer management involves packet dropping and buffer allocation. The overall goal of such schemes proposed in High Speed Downlink Packet Access (HSDPA) is to take advantage of the channel variations between users and preferably schedule transmissions to a user when the channel conditions are advantageous; it does not take in consideration the characteristics of the flows composing the transmitted traffic to the user. This paper compares two queue management mechanisms with thresholds applied for packets transmitted to an end user in HSDPA network. Those mechanisms are used to manage access packets in the queue giving priority to the Real Time (RT) packets and avoiding the Non Real Time (NRT) packets loss. The authors show that the performance parameters of RT packets are similar in the two mechanisms, where as the second mechanism improves the performance parameters of the NRT packets.


Author(s):  
Hemavathy RM

<p>The main focus of the project is to prevent the loss of human life against the discomfort and death caused by the lack of attention towards the patients due to the improper monitoring systems provided in the hospital. The aim of the project is to monitor the bio sensors attached to the persons in their body either internally or externally. The biosensors which are about to be used in this project are EEG sensor (electro encephalogram sensor). An ECG sensor (electro cardiogram sensor) which is very essential for a critical patient, this project also emphasizes on the extended design of a special type of sensor called the oxygen insensitive microscale biosensor which helps in the monitoring of constant oxygen supply in blood thereby detecting blood cancer at the earliest stage. The data from all the sensors are sent to a central wireless node through wifi. From the main node the data is sent to the control station of the hospital through zigbee as the coverage area of certain hospitals is more than the coverage area of a Bluetooth. The control station segregates the data of different patients and stores in the memory location. If any of the patient data exceeds the standard data fed to the control station by the doctor then a message will be sent to the mobile of the attendee and the doctor using the GSM control system.<em></em></p><p><em>Keywords: Biosensors, Raspberry pi (controller), GSM, Zigbee</em></p><p><em> </em></p>


2013 ◽  
Vol 711 ◽  
pp. 440-445
Author(s):  
Xiang Fu ◽  
Chun Ping Lu ◽  
Hao Li

DGreedy (distributed greedy) algorithm evaluates the priority level in view of remaining energy of terminals, and the relationships between neighbor nodes are not considered. At the same time, the adjustable sensing orientations of sensors are limited. Therefore, the network coverage ratio of DGreedy is affected usually by the processing order of sensor nodes. In this paper, an improved Greedy algorithm for the coverage in directional sensor network is proposed based on the principle of global greedy. The single coverage area of nodes is considered as priority. The direction of node with maximum single coverage area is deployed firstly. Thereby it reduces the sensing overlapping regions and accomplishes coverage enhancement of the networks. Meanwhile, in order to improve the network coverage ratio, the sensing orientations of sensors are adjustable continuously, so the best sensing orientation of node can be selected by considering the deployment of neighbor nodes. Simulation experiments show that the proposed algorithm can improve the coverage area effectively.


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