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In this paper, a novel dynamic contention window control scheme is presented to improve the performance and energy efficiency of IEEE 802.11-based CSMA/CA DCF wireless networks operating in ad-hoc mode. The number of competing nodes in physical carrier sense systems has a major influence on the probability of collisions and a subsequent impact on DCF performance and on the energy consumed. A new cross-layer approach to alleviating this problem is developed, which attempts to improve the performance and energy efficiency by controlling the contention window size in the MAC layer according to the number of competing nodes, and the length of the MPDU (MAC Protocol Data Unit) payload according to the physical channel condition in the PHY layer. [ABSTRACT FROM AUTHOR]

Wireless mesh networks based on IEEE 802.11 technology are a scalable and efficient solution for next generation wireless networking to provide wide-area wideband internet access to a significant number of users. The deployment of these wireless mesh networks may be within different authorities and without any planning, they are potentially overlapped partially or completely in the same service area. So in this paper is design a new model to Enhancement Throughput of Unplanned Wireless Mesh Networks Deployment Using Partitioning Hierarchical Cluster (PHC) and using bridge nodes to allow interworking traffic between these WMNs to reduce the performance degradation, the unplanned deployment of WMNs are determinates their performance. [ABSTRACT FROM AUTHOR]

In order to implement a wireless sensor network in process automation system it is needed to specify the sample number for the sensors. Because of the hardware and power supply limitations, wireless sensors are applied to discrete event control system. In wireless sensor network the highest sample number is restricted in comparison to the wired one. Moreover, the lowest sample number is also constrained by the limitations imposed by the control limits values. In this paper, relations between sample number and actuator's frequency drift in discrete domain is formulated and presented. The central and autonomous sensor network structures are introduced. In addition, ways to compromise the sample number with the actuator's frequency and control limits value are acknowledged. An approach to find the optimal sample number is proposed. It is shown when the sensor network becomes larger, autonomous network can partly compensate energy consumption increase by adding the sample number whereas central network does not support this feature. [ABSTRACT FROM AUTHOR]

The recent boom in wireless communications has led to a wide range of new applications. Wireless positioning is an emerging technology which can provide accurate locations for indoor environments when satellite based positioning systems are not available. In this paper, a Session Initiation Protocol (SIP) based system architecture for wireless positioning is described and an overview of how this can be used in overall system design is provided. New simulation results show that SIP is effective as a network signaling protocol for indoor wireless positioning. [ABSTRACT FROM AUTHOR]

The existence of selfish nodes, who do not cooperate in routing and forwarding, menaces the applicability of mobile ad hoc networks (MANETs). In this paper, we propose a novel price-based method for stimulating cooperation among the nodes of a MANET. This method utilizes the game-theoretic notion of core to distribute the earnings of a cooperation coalition among its members in an optimal manner. In this way, a stable costefficient route is established between communicating parties. [ABSTRACT FROM AUTHOR]

As wireless networks evolves towards the 3G and 4G architectures the mobile core networks provides a platform for all-IP convergence of mobile and fixed networks allowing for better integration of the Internet and cellular networks, providing better quality of service, charging mechanisms and integration of different services. Due to this convergence, there have been various evidences of interoperability limitations between the mobile and fixed networks such as protocol adaptation, end-to-end Quality of Service (QoS), charging and signalling interworking. Most of these limitations are currently been addressed by respective standards bodies and various proposals are being implemented. In this paper we investigate the signalling limitations across converged networks which are caused by the use of different Session Initiation Protocol (SIP) profiles for signalling in both mobile and fixed networks. We carried out various performance based simulations on the 3GPP proposed solution in which our results reveal critical shortcomings in the solution. We then proposed a new configuration for the system to enable the solution work more efficiently. [ABSTRACT FROM AUTHOR]

Wireless Sensor Networks (WSNs) are spreading around in multiple fields of applications because they perform measuring tasks in a flexible way. This paper presents a survey on nowadays research efforts on the application of these WSNs to the automobile industry, to agriculture, and to wearable technologies (healthcare and athletes monitoring). From our practical deployments, it is important to highlight the functionalities for the automotive industry, and the results extracted from our application to a vineyard. Research on wearable technologies constitutes a challenge, and wireless healthcare solutions in the context of fabrics are being addressed. [ABSTRACT FROM AUTHOR]

This paper presents a novel network design algorithm for Wireless Local Area Networks (WLANs) considering optimal access point placement and frequency channel assignment problems. The proposed algorithm is a cross-layer approach, accounting the physical layer and the data link layer functionalities of the WLANs in the network design process. Specifically, a multi-objective optimization problem is defined. The proposed objective function separates the physical layer considerations and the data link layer contributions in order to differently change the weights of the two characteristics of WLANs. Numerical results are presented and the jointed impact of the physical and the data link layer functionalities on the WLAN quality of services are evaluated. [ABSTRACT FROM AUTHOR]

Spatial query execution is an essential functionality of a sensor network. Redundancy within a sensor network can be exploited to reduce the communication cost incurred in execution of such queries. Any reduction in communication cost would result in an efficient use of battery energy, which is very limited in sensors. One approach to reduce the communication cost of a query is to self-organize the network, in response to a query, into a topology that involves only a small subset of the sensors sufficient to process the query. In this paper, we design an efficient algorithm for the above problem of self-organization of a sensor network into an optimal logical topology, to reduce energy consumption, in response to a query. We introduce the EEDSOSC algorithm, a new Energy Efficient Distributed Selforganization approximation algorithm for Optimal Sensor Cover that produces a near-Optimal Sensor Cover with minimum consumed energy, minimum connected sensor cover and less message communication overhead. The performance of algorithm is tested for both dense and sparse sensor networks. Through extensive simulations, we have shown that our designed technique result in substantial energy savings in a sensor network. Moreover, experiments have been conducted on networks with different sensors transmission radius, different query sizes, and different network configurations. All experimental tests are evaluated using simulations and the experimental results showed that the proposed approach results in a significant communication cost reduction and an energy efficient near-optimal connected sensor cover. Compared with other techniques, the results demonstrated a significant improvement of the proposed technique in terms of energy efficient query cover with lower communication cost. [ABSTRACT FROM AUTHOR]