Che Soong Kim

Performance Analysis and Optimization of Multi-Traffic on Communication Networks

Promptly growing demand for telecommunication services and information interchange has led to the fact that communication became one of the most dynamical branches of an infrastructure of a modern society. The book introduces to the bases of classical MDP theory; problems of a finding optimal in models are investigated and various problems of improvement of characteristics of traditional and multimedia wireless communication networks are considered together with both classical and new methods of theory MDP which allow defining optimal strategy of access in teletraffic systems. The book will be useful to specialists in the field of telecommunication systems and also to students and post-graduate students of corresponding specialties.

Multi-server queueing system with a Batch Markovian Arrival Process and negative customers

A multi-server queueing system with a finite buffer, where a Batch Markovian Arrival Process (BMAP) arrives, is studied. The servicing time of a customer has a phase-type (PH) distribution. Customers are admitted to the system in accordance with the disciplines of partial admission, complete admission and complete rejection. Except standard (positive) customers, a MAP flow of negative customers arrives to the system. In a random way, a negative customer removes from the system one of the positive customers that are at the server. A stationary distribution of system state probabilities, the Laplace-Stieltjes transformation of the stationary distribution of waiting time, major characteristics of system performance are found. Numerical examples are given.

Approximate method for analysis of queuing models with jump priorities

An approximate method for analysis of the queuing models with jump priorities was developed. It is assumed that upon arrival of a low-priority call one call of such kind might be immediately transferred to the end of the queue of the high-priority calls. The transfer probabilities depend on the state of the queue of heterogeneous calls. Consideration was given both to the models with separate and common queues. Algorithms to calculate the quality of service metrics of such queuing models were described, and the results of the numerical experiments were presented.

An Analytical Approach to the Analysis of Guard-Channel-Based Call Admission Control in Wireless Cellular Networks

We develop an analytical approach to the performance analysis and optimization of wireless cellular networks for which different types of calls are prioritized based on a channel reservation scheme. We assume that the channel occupancy time differs for new and handover calls. We obtain simple formulas for calculating quality of service (QoS) metrics and solve some problems related to finding the optimal values of guard channels as well as present the results of numerical experiments.

A unified approach to analyzing models of cellular communication networks with data call buffering

A unified approach to the analysis of models of cellular communication networks with queues of data calls was developed. Consideration was given to the models with two types of strategies for admission to the cell channels and the buffer. In one strategy, admission to the voice call channels is based on reservation of channels for handover of calls of the given type, and in the other strategy, on the scheme of truncating the calls of the given type. In both models, the strategy of buffer admission by the data calls relies on the scheme of place reservation for handover of the calls of the given type. The models with finite and infinite data call queues were studied. For different admission strategies, algorithms to calculate the servicing performance indices were given, and the results of their comparative analysis were presented.

Performance Analysis of Multi-Parametric Call Admission Control Strategies in Un-Buffered Multi-Service Cellular Wireless Networks

In this paper model of integrated voice/data cellular wireless networks (CWN) are investigated. The unified approximate approach to calculate the desired Quality of Service (QoS) metrics in an isolated cell of such networks under two multi-parametric call admission control (CAC) strategies is developed. One of them is based on the guard channels scheme while the second is based on a threshold scheme. Results of the numerical experiments are given and a comparison of QoS metrics under different CAC strategies is carried out.

QoS Optimization Problems in Cellular Wireless Networks

The algorithms suggested in previous chapters for calculation of QoS (Quality of Service) metrics of integrated voice/data Cellular Wireless Networks (CWN) allow one to optimize their values in terms of defined QoS requirements. QoS requirements can be defined say by indicating upper bounds for the loss probabilities of original (o-calls) and handover calls (h-calls) of heterogeneous traffic as well as lower bounds for the number of busy channels. In this chapter some optimization problems for both cells without queues and with queues are considered. For the sake of simplicity we consider optimization problems for mono-service networks and we have attempted as much as possible to retain the notation from previous chapters.

Parametric Optimization Problems in Multi-Rate Systems

Some access strategies investigated in the previous Chaps. 4 and 5 contain controllable parameters. In other words, by the choice of suitable values for these parameters, it is possible to optimize the QoS metrics of the investigated systems. Such problems we shall name problems of parametric optimization. In the present chapter similar problems for multi-rate queues (MRQ) are considered and algorithms are proposed for their solution. Realization of the results of the considered problems in real multimedia systems does not present any difficulties.

Models of Mixed Multi-Rate Systems

In this chapter models of multi-rate systems in which inelastic and elastic calls are jointly serviced are investigated. Elasticity of a call means that its width (i.e. the number of channels needed to service it) may vary as a function of the number of free channels. In such systems channel utilization may essentially be improved. Note that such models are not only of theoretical interest, but also of great interest for practical applications. In fact, in view of the development of the technology of coding and compression, some types of multimedia information in networks may be adapted to the available number of free bands. There are quite a number of such examples in telecommunication networks (cf. [3–5]).

Performance Analysis of Call-Handling Processes in Buffered Cellular Wireless Networks

In this chapter effective numerical computational procedures to calculate QoS (Quality of Service) metrics of call-handling processes in mono-service Cellular Wireless Networks (CWN) with queues of either original (o-calls) or handover (h-calls) calls are proposed. Generalization of the results found here for integrated voice/data CWN is straightforward. Unlike classical models of mono-service CWN, here original and handover calls are assumed not to be identical in terms of time of radio channel occupancy. First we consider models of CWN with queues of h-calls in which for their prioritization a guard channels scheme is also used.