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Relay communication network is a technique to obtain spatial diversity by using one or more relay terminals in order to improve the transmission performance. Amplifty-and-forward (AF) and decode-and-forward (DF) are two kinds of fixed relaying protocols and widely researched now. In this paper the performance of AF and DF in terms of the outage probability and the symbol error rate (SER) is analysed...
The onset of muscle contraction has been an important element in the understanding of human motor control system as well as in the development of medical devices. This task is problematic in the study of spasticity using surface Electromyography (sEMG). In fact, spasticity is characterized by involuntary muscle contractions that can be seen as both, a non-stationary background if they are weak or...
This paper deals with logical cryptanalysis of hash functions. They are commonly used to check data integrity and to authenticate protocols. These functions compute, from an any-length message, a fixed-length bit string, usually named digest. This work defines an experimental framework, that allows, thanks to the propositional formalism, to study cryptosystems at the bit level through corresponding...
In this paper, we develop a mathematical model of a load control mechanism for SIP server signaling networks based on a hysteretic technique. We investigate loss-based overload control, as proposed in recent IETF documents. The queuing model takes into account three types of system state — normal load, overload, and discard. The hysteretic control is made possible by introducing two thresholds, L...
Threshold load control is one of the key tools in preventing overload in telecommunication networks. Its implementation as hysteretic control mechanism is used for detecting and mitigating congestion in Next Generation Networks, where session initiation protocol is the main signalling protocol. In this paper single-server finite capacity queuing system with constant service time, poisson input flows...
In this paper, we present the analysis of the new transmission algorithm of RFID in form of multichannel which has been developed from frame slotted ALOHA protocol. By using concept of the tag transmission group division which differ in slot access ability and the multinomial distribution foundation for calculate each probability of successful transmission slots. And compare with the ordinary frame...
In this paper a new mathematical model, describing the behavior of simplified Constrained Priority Countdown Freezing (CPCF) protocol, is introduced. The CPCF protocol sets constrains on DCF countdown mechanism and thus requires different mathematical model from those found in the literature. For this reason, the two-dimensional Markov chain analytical model is developed in order to accurately quantify...
The open and distributed nature of the IEEE 802.11 based wireless networks provides selfish users the opportunity to to gain an unfair share of the network throughput by manipulating the protocol parameters, say, using a smaller contention window. In this paper, we propose an adaptive approach for real-time detection of such selfish misbehavior. An adaptive detector is necessary in practice, as it...
This paper presents a novel mathematical model for Anti-collision protocols based on Framed Slotted Aloha scheme. Using recursive calculations, the proposed model accurately estimates the probability of discovering tags in multiple rounds discovery system. First, the model estimates the probability of detecting a given number of tags in one single interrogation round. Then using a probability map,...
Pervasive computing environments consist of thousands of heterogeneous devices and network services. Service discovery protocols provide essential functionalities for users and client devices to discover and access services. Most existing protocols, however, only support discovery via static service attributes. Dynamic information such as service conditions, quality, and reliability is not available...
In this paper, we propose a new semi-Markov process based model to compute the network parameters such as saturation throughput, for the IEEE 802.11 Distributed Coordination Function (DCF) employing the Binary Exponential Backoff (BEB). The backoff stages of BEB and their backoff intervals are modeled as the states of semi-Markov process and their state holding-times, respectively. The proposed model...
Multi-hop broadcast routing is a critical component in ad-hoc wireless networks. Vehicular ad-hoc network (VANET) applications for example use broadcast communications extensively. Efficient broadcast protocols are required to enable these applications. Multi-hop broadcast algorithms can roughly be classified as either topological or statistical. Statistical protocols are well-suited to applications...
End-to-end QoS is a challenge for future Internet. A per flow resource reservation can be carried out among heterogeneous domains on the communication path using signaling protocols. When one or both communicating terminals are mobile there is additional complexity. Signaling delays and resource lacking on future paths can dramatically impact user experience. In this paper, a rational future path...
This paper addresses the problem of MAC performance evaluation of a contemporary IEEE 802.11 WLAN. The network is observed under saturation conditions and the packet transmission probability analysis is conducted with the novel regenerative approach. The proposed model accounts for collision resolution protocol parameters, packet retry limit, coexistence of unicast and broadcast traffic, and heterogeneous...
Many ad hoc network applications rely on nodes having accurate knowledge of their geographic locations. However, inherent in all localization systems is a degree of error in computed positions, which can compromise the accuracy and efficiency of location dependent applications and protocols. We propose a method in which nodes estimate the amount of error present in their derived positions with a certain...
Minimizing the sensing activity during the pre-attack phase while meeting the performance requirements is critical for reducing the operational costs of chemical sensor networks. In this paper, we present a formal problem formulation for this optimization problem, and propose a decentralized, dynamic sensor activation protocol for meeting this goal. We analyze the behavior of the activation protocol...
This paper introduces a new localization algorithm called COM-LOC++ that improves the performance of a recently introduced distributed range-free algorithm called COM-LOC. COM-LOC and other existing range-free algorithms only process the information received from one reference node in order to estimate the distance to that reference node. COM-LOC++ improves this performance by processing the information...
In this paper, we describe the cognitive radios sharing the spectrum with licensed users and its effects on operational coexistence with unlicensed users. Due to the unlicensed spectrum band growing needs and usage by many IEEE 802.11 protocols, normal wireless radio operation sees high interference leading to high error rates on operational environments. We study the licensed bands and the characteristics...
Here we propose an analytical model of energy usage hierarchical wireless sensor network protocols such as LEACH [1]. LEACH has been used as a foundation for much of the wireless sensor network research, so results addressing the underlying nature of these systems build understanding of a wide range of existing protocols. First, we derive the probability density functions of the distance to the nearest...
Probabilistic model checking is a powerful technique for formally verifying quantitative properties of systems that exhibit stochastic behaviour. Such systems are found in many domains: probabilistic behaviour may arise, for example, due to failures of unreliable components, communication across lossy media, or through the use of randomisation in distributed protocols. In this paper, we give a short...
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