this paper, two models dealing with the call retrial phenomenon are presented. The first model considers a base station with a finite customer population and repeated attempts. A Markovchain modeling is proposed and a recursive solution of the state probabilities is presented. The second model focuses on the use of the guard channel concept to prioritize the handover traffic. Again, the retrial phenomenon plays an important role. The influence of the repeated attempt effect on the quality of service experienced by the mobile customers is discussed by means of numerical results

This paper presents a demand-based engineering method for designing radio networks of cellular mobile communication systems. The proposed procedure is based on a forward-engineering method, the Integrated Approach to cellular network planning and is facilitated by the application of a new discrete population model for the traffic description, the Demand Node Concept. The use of the concept enables the formulation of the transmitter locating task as a Maximal Coverage Location Problem (MCLP), whichiswell known in economics for modeling and solving facility location problems. For the network optimization task, we introduced the Set Cover Base Station Positioning Algorithm (SCBPA), which is based on a greedy heuristic for solving the MCLP problem. Furthermore, we present the planning tool prototype ICEPT (Integrated Cellular network Planning Tool), which is based on these ideas and show a first result from a real world planning case.

This paper discusses and compares the performance of three easy-to-implement congestion detection schemes for ATM switches supporting the ABR service category.

... In this paper, we discuss link dimensioning for a typical CDMA encoder. We consider a T1/E1 link extending between a CDMA basestation and the Mobile Switching Center. Traffic from various voice sources is subject to a framing scheme, which presents a semi-periodic batch input at the T1/E1 interface cards. We analyze the resulting queuing system using discrete-time analysis and verify our results through simulation. Our results show the accuracy of the analysis and the potential statistical gain that can be achieved by voice packetization.

In this paper we present an analysis of the discrete-time Geo/D/N -# queue. This model has been recently applied as an asymptotic model in performance studies of various modern telecommunication systems. The distribution of the number of customers at arbitrary discrete time instants and the corresponding arrival distribution are derived. Using these results the waiting time distribution is obtained. The results are of an exact nature and the presented algorithm is of low complexity with respect to computation time and memory usage. 1 Introduction In the performance evaluation of modern telecommunication systems basic discrete-time queueing systems are frequently applied for system modeling. A special class of queueing systems used to investigate the burst scale performance of ATM multiplexers is formed by queueing models with multiple deterministic servers ([Kam96], [GBSM96]). In this paper we focus on the discrete-time Geo/D/N -#queueing system. While analytical approaches for ...

Weighted Finite Automata (WFA) exploit self-similarities within single pictures and also sequences of pictures to remove spatial and temporal redundancies. Their implementation then combines techniques from hierarchical methods related to quadtrees and from vector-quantization to achieve performance results for low bit-rates which can be put on a par with state-of-theart wavelet codecs like set partitioning in hierarchical trees. Due to their simple mathematical structure, WFA provide an ideal platform for efficient hybrid compression methods. Therefore, WFA were chosen as a starting point for a fractal-like video-compression integrating a hierarchical motion-compensation as well as an option to vary compression--quality between "centers of interest" and "background" in a flexible manner. Keywords: Weighted Finite Automata, video coding, fractals, hierarchical motion compensation, locally variable compression quality 1 Introduction Recently, the need of efficient image compression sy...

... this paper we model the user distribution in a cell by a planar point process and derive measures of the spatial multiplexing gain.

Currently, a lot of interest is paid to multimedia traffic in general and to video traffic in particular. Most of the studies deal with appropriate models for this complex type of traffic and use trace-driven simulations to assess the performance of high-speed networks carrying this type of traffic. In contrast, we develop two models of different correlation complexity and apply them in a discrete-time analysis of a buffer with variable bit rate (VBR) MPEG video traffic input. The algorithms are easy to implement and provide good cell loss estimates over a wide range of buffer sizes.

Production processes where several jobs are loaded into a single machine and processed simultaneously are common in semiconductor manufacturing. These machines are called batch servers. In this paper, we extend previous studies of batch servers introducing two job classes. One job class receives privileged service to model prioritized jobs. To study the impact of the percentage of prioritized jobs on the system performance we utilize the discrete--time analysis technique, widely used for the performance evaluation of modern communication systems. The intent of this paper is to present first results and to demonstrate the feasibility of discrete-time analysis technique for operational research in semiconductor manufacturing rather than to attempt any rigor mathematical treatment of the numerical algorithms.

The Guaranteed Frame Rate service recently defined by the ATM Forum allows users to send data in excess of their guaranteed service rate but only guarantees that such traffic will be delivered within the limits of available network resources, that is, it is transported on best effort. In order to distinguish traffic sent in line with the guaranteed service rate from traffic sent in excess, a frame-based version of the Generic Cell Rate Algorithm is employed. This paper presents an analytical approach that forms the basis for dimensioning traffic descriptors related to the Frame-Based Generic Cell Rate Algorithm. The approach is based on a discrete-time analysis technique.