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The base station in IEEE 802.16, or WiMAX, networks allocates contention-based time slots for the mobile stations to transmit their requests for additional bandwidth. Using a technique called subchannelization, multiple concurrent transmissions by mobile stations can be admitted by the base station during the same contention period. For transmission during this period, each station employs a contention-resolution...
The WiMAX channel access is controlled by one of the several available Medium Access Control (MAC) procedures. This paper studies the contention-based bandwidth request procedure based on our original analytical model, facilitated by numerical analysis and simulation. We optimize the key parameters of the contention procedure in order to minimize the average bandwidth access delay, thus ensuring the...
Cognitive radio networks (CRN) are subject of a multidisciplinary research in wireless networking, digital communications, artificial intelligence, and other fields. Special emphasis is given to investigation of the CRN capability of improved RF spectrum utilization by means of dynamic spectrum access (DSA). This paper proposes a new analytic framework for modeling the adaptive behavior of CRN. In...
In wireless communication system, power saving mechanism is a key issue since a mobile station operates depending on limited power. Hence, the IEEE 802.16e system provides three types of power saving classes (PSC I, PSC II and PSC III) for the mobile station (MS) to reduce power consumption. Many models have been made to analyze the performance of power saving mechanism (PSM) of the IEEE 802.16e system...
In this paper, we propose a translation-based approach for performance prediction of composite service built on WS-CDL. To translate a composite service into a state-transition model for quantitative analysis, we first give a set of translation rules to map WS-CDL elements into general-stochastic-petri-nets (GSPN). Based on the GSPN representation, we introduce the prediction algorithm to calculate...
In this paper, we consider wireless mobile sensor networks under extreme environments where nodes: 1) have local knowledge; 2) have limited computational power; 3) make distributed decisions; and 4) move rapidly over time. Information dissemination in these networks (or gossip) can be modeled via epidemic models that analyze behavior of the system mimicking the way diseases spread (or even gossip...
Data streaming (DS) over peer-to-peer (P2P) networks has been intensively studied in recent years and there have been various schemes proposed already. To evaluate these schemes, either measurement in experimental implementations, or simulation and theoretical analysis have been used. The former is inadequate as data are collected from different experiments, while the latter lacks a proper theoretical...
In this paper we study the overhead introduced by secure functions in considering two models of non-repudiation protocols. The models are specified using the Markovian process algebra PEPA. The basic model suffers from the well known state space explosion problem when tackled using Markov chain analysis. Following previous study of performance modelling on security protocols, mean value analysis and...
This paper proposes a strategy to associate Statecharts with a Markov Decision Process for performance evaluation. Statecharts are adapted to represent the possible decision choices and the costs incurred from decisions. Markov Decision Process is used to evaluate the long term effects of decisions. This strategy can aid users without a good knowledge of the performance evaluation process, and may...
Carrier sense multiple access with collision avoidance (CSMA/CA) is one of the basic media access control (MAC) protocols specified in the IEEE 802.11 to support many stations to share a channel in the network. This paper analyzes how the performance of CSMA/CA is affected by the back-off time. We propose to use random back-off time and simulation results show that it can achieve better performance...
The conventional reaction after detecting an attacker in an information system is to expel the attacker immediately. However the attacker is likely to attempt to reenter the system, and if the attacker succeeds in reentering, it might take some time for the defender's intrusion detection system (IDS) to re-detect the attacker's presence. In this interaction, both the attacker and defender are learning...
Software evolution is an important activity in software life cycle. The Web application is very different from traditional software in design and composition. It needs maintained more frequently. So the automatic evolution support is a critical part in Web engineering. This paper uses Markov chain to model Web userspsila browser behavior by statistic analysis of Web log. And transition probability...
The modern-day system-on-chip communication posses complex characteristics- (a) the communication times of individual transactions are difficult to predict, (b) concurrent communication techniques are employed to meet the performance of emerging applications, and (c) communication is hierarchical. Thus, performance of communication architecture plays major role in determining the performance of the...
In CDMA cellular networks the variation in soft handoff coverage area can be taken as the parameter influencing the performance of the system. In this paper, an analytical model is developed and analyzed for the concerned target cell in CDMA cellular network. The model proposed in this paper is for integrated data and voice services. It is based on reservation for handoff voice and data calls along...
It has been reported that Internet Protocol (IP) packet traffic exhibits self-similarity or long range dependence (LRD) and causes the degradation of switch performance. Therefore, it is crucial for an appropriate buffer design of switch. In this paper, we investigate the packet loss behavior of the switch under self-similar variable packet length traffic by modeling it MMPP/M/1/K as queueing system...
This paper presents an analytical model which extends Markov Chain models previously proposed for IEEE 802.11 data link protocol. Unlike already published models, the proposed Markov Chain accounts jointly for the following three factors. First, in addition to collision, it accounts for frames that may be lost due to a low signal-to-noise ratio value at the link receiver (frame corruption). Second,...
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