Toni Janevski

Modelling and simulation of IEEE 802.11a wireless local area networks using SDL

In this paper we present a comprehensive and standalone SDL-based model for performance analysis and planning of IEEE 802.11a wireless local area networks (WLANs). It is based on the obtainable behavior code from the IEEE 802.11 standards committee. We have made all the necessary improvements to provide efficient way for simulation of the IEEE 802.11a based WLAN. Our performance model encompasses the entire 802.11a MAC and PHY functionalities. It is further developed with several alternative types of channels. The simulation model is validated via extensive simulation scenarios regarding the WLAN performances. We verified that the developed simulation model for 802.11a networks can be efficiently used in analysis, planning and optimization of 802.11a wireless networks for different types of services and for different environments

Unified billing system solution for interworking of mobile networks and wireless LANs

In this paper we present an applicative solution for a billing system for interworking between public land mobile networks and wireless LANs. The integration between two networks is based on the authentication and accounting mechanisms. We have developed WLAN access controller and WLAN billing system, which provide access control as well as charging and billing functionalities for the WLAN service, respectively. The developed solution gives cost-effective and easy-to-deploy PLMN-WLAN interworking scenario

Empirical modeling of Internet traffic at middle-level burstiness

In this paper we use empirical data from Internet traffic measurements. Collected measurements are analyzed for different protocols, such as TCP and UDP. We perform statistical analysis through the correlation coefficients, covariance, and self-similarity degree, i.e. Hurst parameter. Our experimental studies captured traffic with Hurst parameter around 0.7-0.75, which is near half way between values of 0.5 (it is not a self-similar) and 1 (strong self-similar properties). We use maximum likelihood approach to fit the obtained time series to existing distributions, such as Pareto and exponential distribution, where the first one is a self-similar process and the second is not. The analysis pointed out that Internet traffic with such values for the Hurst parameter could be modeled with similar accuracy using both Pareto and exponential distribution.

Dynamic optimization of quality of service in cellular multi-class networks using variable number of guard channels

In this paper we propose a novel strategy for channel allocation in multi-class mobile networks with prioritized handovers, which uses dynamically variable guard channels to improve network utilization under given quality of service (QoS) constraints. We define user classes, each of them with different utilization of network channels. We consider the guard channel policy where certain number of channels is dedicated to handover calls, and also, the policy in which this number of channels is dynamically adapted to the network requirements. Our target is to obtain the influence of this methodology over performance parameters, such as call blocking and call dropping probability. Traffic, network and mobility parameters are also taken into account, such as cell capacity, traffic intensity, as well as number and distribution of subscribers per classes.

Design of applicative quality testing system for data services in mobile networks

Mobile operators nowadays have plenty of data services and this number is increasing towards future 3G LTE mobile networks. There are IP-based services which were migrated from wired to mobile networks, such as HTTP, FTP and E-mail. But, also mobile specific services were created such as WAP and MMS. On the other side, behavior of mobile services is influenced from the environment, the terrain, interference, from protocols on different OSI layers, from user behavior, etc. Therefore, mobile operators need to examine their network and be assured that services are performing well. In this paper we describe an applicative solution for Service Quality Testing System (SQTS), which provides efficient way for testing of all data services, including bearer as well as IP-based services in mobile networks from the user point of view, through a defined set of Key Performance Indicators. We define all SQTS functionalities as well as all needed networks nodes for its functioning. The proposed system is robust and scalable regarding definition of new services that will appear in future.

Performance Evaluation and Modeling of IEEE 802.11a WLAN Based on SDL Simulation

In this paper we present a novel, comprehensive and standalone SDL-based model for performance analysis and planning of IEEE 802.11a Wireless Local Area Networks (WLANs). We have developed our model using the obtainable code from the IEEE 802.11 standards committee, with all necessary improvements to provide efficient tool for simulation of the IEEE 802.11a WLANs. We have verified the developed simulator through extensive simulations targeted to Medium Access Control layer and physical layer, which has shown that it can be used as an efficient tool in analysis, planning and optimization of 802.11a wireless networks for different types of services and for different environments.

Analyses of MPEG-4 video streams processing in computer clusters based on multihop ATM networks

The introduction of the MPEG-4 standard for interactive digital video necessitates investigations of the properties of MPEG-4 video streams and their processing and transport in distributed systems. Of special importance are the issues affecting MPEG-4 video applications, such as the functionality of network software layers and their impact on the overall quality of service (QoS). In this paper we present an analysis, based on simulation modeling, of the processing and transport of MPEG-4 video in computer clusters connected with multihop ATM networks. Through simulation experiments we obtain results for the QoS parameters (transfer delay, jitter, and the loss rate of cells), average buffer occupancy in the ATM multiplexers along the path of the video streams, and the influence of the AAL protocol layers on the performance of the transfer.

Applicative solution for testing the quality of data services in mobile networks

Mobile operators nowadays have plenty of data services, since the introduction of GPRS and this number is increasing towards future 3G LTE mobile networks. There are IP-based services which were migrated from wired to mobile networks, such as HTTP, FTP and E-mail. But, also mobile specific services were created such as WAP and MMS. On the other side, behavior of mobile services is influenced from the environment, the terrain, interference, from protocols on different OSI layers, from user behavior, etc. Therefore, mobile operators need to examine their network and be assured that services are performing well. In this paper we describe an applicative solution for service quality testing system (SQTS), which provides efficient way for testing of all data services, including bearer as well as IP-based services in mobile networks from the user point of view, through a defined set of Key Performance Indicators. We define all SQTS functionalities as well as all needed networks nodes for its functioning. The proposed system is robust and scalable regarding definition of new services that will appear in future.

Applicative quality testing system software for IP-based services in mobile networks

Mobile operators nowadays have plenty of data services, since the introduction of GPRS and this number is increasing towards future 3G LTE mobile networks. There are IP-based services which were migrated from wired to mobile networks, such as HTTP, FTP and E-mail. But, also mobile specific services were created such as WAP and MMS. On the other side, behavior of mobile services is influenced from the environment, the terrain, interference, from protocols on different OSI layers, from user behavior, etc. Therefore, mobile operators need to examine their network and be assured that services are performing well. In this paper we describe an applicative solution for Service Quality Testing System (SQTS), which provides efficient way for testing of all data services, including bearer as well as IP-based services in mobile networks from the user point of view, through a defined set of Key Performance Indicators. We define all SQTS functionalities as well as all needed networks nodes for its functioning. The proposed system is robust and scalable regarding definition of new services that will appear in future.

Integrated AAA System for PLMN-WLAN interworking

In this paper we propose an applicative solution for authentication, authorization and accounting i.e. AAA system for interworking between public land mobile networks (PLMN) and wireless local area networks (WLAN). The developed solution is based on several networks nodes, such as WLAN access controller, WLAN AAA gateway, AAA server, as well as necessary network elements for dynamic allocation of IP addresses and Web-server for user access to the network. WLAN access controller, together with the AAA server, provides access control functionality for WLAN users. WLAN AAA gateway provides charging and billing functionalities for the WLAN service. The integrated AAA system with all network elements gives an efficient solution for PLMN-WLAN internetworking.