Pavel Vajsar

Predicting user QoE satisfaction in current mobile networks

Intensive competition between network operators as well as steady increase in mobile traffic call for additional investments into the networking infrastructure. Keeping current mobile networks profitable, the following criteria should be satisfied: end-user quality expectations need to be fulfilled on the one hand and service quality overprovisioning should be eliminated on the other. This generates growing demand for adequate QoE estimation models accounting for dominant mobile data services. Moreover, novel models have to fulfill requirements of good applicability and high accuracy. Our approach in this paper details an advanced QoE estimation model, extensively verified with appropriate statistical tools, for the most popular mobile web services: browsing, download, and upload. The proposed model follows from a recent extensive QoE assessment and utilizes the bitrate together with the initial loading delay as well-measurable input parameters. Targeted to estimate the mean opinion score, our proposed model demonstrates an excellent convergence across the considered practical scenarios.

User's happiness in numbers: Understanding mobile YouTube quality expectations

Our major contribution is to propose QoE assessment methodologies for mobile YouTube which is currently the most prominent on-line video portal. For this purpose we designed two assessment methodologies which are reflecting real usage scenarios. The focus is given on different variables: the video streaming profile, end user device and overall conditions. Furthermore, the implementation of various test conditions into the test methodology is explained and both quality ratings are described in details. Finally, rating types are compared and their performance and contributions are discussed on selected YouTube QoE results.

Mobile web QoE study for smartphones

The mobile web traffic is growing rapidly due to service accessibility in densely populated areas and massive usage of smart hand held devices (smartphones, pads and Internet dongles). This is a challenge for mobile operators and service providers, because it forces systematically increasing network throughput capacity and in parallel to keep this investment on profitable basis. On the other side, the user satisfaction with mobile broadband service should be considered as well, in order to balance the user expectations and mobile operator investments. Our work provides extensive QoE study for different conditions in sense of mobile web service, web content, network conditions and end user device. Finally, the obtained results create basis for more dimensional overview of mobile web QoE and allow to recognize quality and saturation thresholds based on network parameters.

Advanced trajectory management techniques for mobile nodes in OPNET Modeler environment

The goal of each simulation is to get a situation with conditions approaching the real environment. The results obtained are more accurate and more in a line with network behaviour in real environment. One of the most important parameters of Mobile Ad hoc Networks (MANET) is the mobility of network nodes. Each mobile node may change its location with a specific rate depending on the time. The simulation environment OPNET Modeler enables to control a trajectory of each network station by several ways. This paper presents the possibility to control the movement of mobile node based on information about the route stored in the GPX file. This GPX file was originated from a simplified map source. The development process of the simulation scenario and obtained results are presented in this paper.

QoS support in routing protocols for MANET

This paper deals with the characteristics of mobile ad-hoc networks and the issue of quality of service assurance in these networks. The work is focused mainly on the routing protocol AODV and its ability to provide different processing probabilities for different types of network traffic. Firstly, the development of the MANET simulation model and implementation of AODV protocol are described. The Network Simulator 3 was used as the key software tool for this purpose. The analysis of the efficiency of QoS mechanism implemented into AODV protocol and the final evaluation are posted at the end of this paper.

Monitoring and management system for wireless sensor networks

Wireless sensor networks (WSN) can be used in many deployed and in many areas. For the wireless sensor network monitoring is important a tool, which is able to provide information about the network and which is able to collect and represent required data from the network. This paper describes the solution called WSN Monitor, which is able to monitor wireless sensor network. The solution is divided into the several parts such as the database storage for collect a data from a wireless sensor network, client and server side applications, Fig. 1. This paper describes the solution requirements, architecture and used technology for develop the solution. The solution was tested for real time monitoring RSS (Received Signal Strength) value in the real wireless sensor network. The second part of this paper brings describe the measurement method, input problems, the results and the evaluation of the measurement values.

Map-based direct position control system for wireless ad-hoc networks

The mobility modelling is one of the most important issues in wireless ad-hoc networks, therefore our research activities are focused on this area. This paper presents a new solution for map-based mobility modelling system which enables direct position control for mobile stations. This system, based on the cooperation model between OPNET Modeler simulation environment and MATLAB tool, provides fully automated process of direct position control with respect to the initial requirement and attributes. Firstly, the input information are collected in OPNET Modeler and forwarded to MATLAB environment. After that, MATLAB process a map source stored as a bitmap image and runs the function which generates a set of coordinates. These coordinates are transferred back to OPNET Modeler and used for the direct movement control of mobile stations. Our system developed was evaluated by the set of simulation runs and the results are placed on the end of this paper.

Design of QoS model for mobile Ad-hoc network

This paper deals with the characteristics of MANET and issues of the quality of service support with using the DSDV routing protocol. In this paper, the creation of the process model of MANET with DSDV routing protocol in a simulation environment NS-3 and its complement of QoS support are elaborated. The implementation of QoS support algorithms is verified by the functional simulation model and consequently analyses of achieved results. Comprehensive evaluation including enunciation effectiveness of the implemented QoS method is mentioned at the end of this paper.