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IEEE802.16 is the standard defining the Worldwide Interoperability for Microwave Access (WiMAX) for Metropolitan Area Network (MAN). WiMAX has recently being considered by Internet Service Providers (ISPs) as an attractive alternative to leasing lines from current ISPs or the deployment of new fiber networks. This is mainly the case since WiMAX is more flexible and much cheaper than other possible solutions. Our focus in this paper is on mobile WiMAX i.e. IEEE802.16e designed to provide broadband wireless access for mobile users. In this paper we have designed various scenarios using the Qualnet simulation package to evaluate the performance of WiMAX in delivering traffic under different operational conditions for a point to multi point configuration. The results showed how different factors such as load and mobility might affect the performance of WiMAX in a single cell environment. End to end delay, delay jitter and throughput were considered as the performance measures in this study. [ABSTRACT FROM AUTHOR]

User's perceptive video quality differs greatly with video contents hence, it is of practical importance to classify videos. Videos are most commonly classified according to their spatial and temporal features. In this paper, we classify videos into groups based on objective video quality evaluation. Video quality measured in terms of the Mean Opinion Score (MOS), obtained by the application and network level parameters is classified into groups using cluster analysis with good prediction accuracy. The QoS (Quality of Service) parameters that affect video quality considered in this paper are send bitrate, frame rate in application and packet error rate in the network level. We then find the degree of influence of each of the QoS parameter and analyze the relationship between QoS parameters and content types by using principal component analysis for streaming MPEG4 video over wireless networks. We compare our classified contents to the spatio-temporal dynamics of the content and establish the relationship between video contents and video quality by equations obtained by multiple linear regression. Finally, we apply the results to rate control methods. The proposed scheme makes it possible to apply priority control to content delivery, based on content types with similar attributes. [ABSTRACT FROM AUTHOR]

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]

The widespread popularity of mobile computing devices, such as Laptops, handheld devices and cell phones, as well as recent advances in the wireless communication technologies have motivated researchers to provide novel solutions and applications for the users that were previously not feasible. The users of these mobile computing devices expect the same features and services from these devices as were previously available from conventional desktop computers. However to provide mobility and reduction of size of these mobile devices, the battery life is a major concern; several hardware based techniques have been proposed which results in more energy efficient systems as compared to the earlier systems. Even after these hardware improvement based techniques the problem still persists and it is believed that software based techniques have enough potential to reduce the energy demand to overcome the problems faced due to energy limitation. In this paper, we look into the problem of distributing the computational tasks among different devices in hybrid network environment. By hybrid networks we mean a network containing both wired as well as wireless handheld devices. The reason of selecting hybrid network environment is because most of the applications of mobile devices require accessing resources on the high bandwidth unlimited energy devices connected on wired network to help conserve the energy utilization of the energy limited wireless handheld devices. We have proposed a novel energy-aware scheduling algorithm to solve the problems of resource constrained mobile devices. Our scheduling algorithm schedules a set of computational tasks which may have operational and communication dependencies, into the set of heterogeneous devices so as to minimize both the energy consumption and time taken by the tasks to be completed. Experiments show that significant improvement in the over all performance in terms of energy consumption and execution time of the handheld devices can be achieved by using our algorithm. [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]

an increase number of wireless applications consist of a network of mobile nodes moving together in high velocity, existing protocols focused on roaming of single node, and there are no mature solutions to keeping uninterrupted high-speed mobile communications for roaming the entire subnet with a moving velocity as high as a vehicle. In this paper, firstly we propose the idea of the new handover scheme based on mobile IP, and then introduce the principle and key issues for subnet mobility in networks. The station (STA), a wireless communications equipments in mobile wireless subnet, taking the access point (AP) as the gateway, implements the multiple-hop subnet mobile IP by cooperation of the home agent, the foreign agent, interior network routing agent and reused tunneling, thus to overcome the limitation of one hop between the movement node (MN) to the exit of the tunnel. A dynamic next AP scanning and finding model and a handover trigger model named Well-time is designed to provide low latency. We implement the scheme on re-designed STA and AP, the experiment shows that the new scheme enables a mobile subnet to handover seamlessly across heterogeneous wireless networks and maintains all ongoing high-speed communications with the nodes in fixed networks, when moving at a high velocity up to 50km/h. [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]

Minimization of power consumption is a critical design goal for wireless-relay networks comprised of battery-powered sensor devices. In the paper, we consider a source-initiated (one-to-all) broadcast scenario in wirelessly-relay sensor networks (WSNs) with a high delivery probability requirement. We analyze both the transmission and the reception power to gain insights into the optimization of the overall power consumption of WSNs at network planning stage. Specifically, at the network planning stage, one wishes to maximize the network lifetime of the network through a proper selection of three key design parameters including the transmission range, the sleep period, and the broadcast probability. As a rule of thumb, the optimal number of nodes awaken to broadcast messages within a transmission range is constant with a given network size and path loss exponent for a target delivery probability requirement. Given the optimal settings above, we also present the trade-off between the delay requirement and power consumption. Our results can serve as general guidelines at the network planning stage. [ABSTRACT FROM AUTHOR]

An ad hoc network (MANET) has no fixed networking infrastructure, and consists of mobile nodes that communicate with each other. Since nodes are mobile, Routing in ad hoc network is a challenging task. Efficient routing protocols can make better performance in such networks. Many protocols have been proposed for ad hoc networks which the most common types are: Ad hoc on-demand Distance Vector (AODV), Dynamic Source Routing (DSR), Optimized Link State Routing (OLSR). In this paper, we introduce a new Position and Neighborhood based Routing (PNR) algorithm for mobile ad hoc networks which uses GPS and new algorithm to reduce the overhead caused by position update messages. We also compare our scheme with DSR, AODV, OLSR for two metrics: packet delivery ratio and end-to-end delay. We use GlomoSim [1] to evaluate these protocols. [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]

Maintenance of the cache consistency is a complicated issue in the wireless mobile environment. Caching of frequently accessed data items on the node can reduce the bandwidth requirement of the mobile node environment. In this paper, we present a new technique called Modified Energy Efficient Cache Invalidation Algorithm (MEECIA) especially to reduce the uplink bandwidth consumption in the wireless ad-hoc network, by choosing following modes: Slow, Fast, Super-fast. The mode is selected based on threshold specified for time and the number of node requesting the updated data to other node. Simulation results demonstrate that our algorithm is efficient in improving mobile caching, reducing the communication bandwidth and also efficiently utilizing the energy in ad-hoc network. Compared to the previously reported cache based Invalidation Report (IR), our scheme can significantly improve the performance in terms of energy consumption and reduce the query latency in ad-hoc network. [ABSTRACT FROM AUTHOR]

In this paper we propose an approach to improve the performance of existing flood based routing algorithm Ad-hoc on demand Distance Vector Routing [2] for mobile Ad-hoc wireless networks based on heuristic searching technique. Flooding technique is often used for route discovery in on demand mechanism in MANET such as AODV, DSR. To avoid the problem of wireless broadcast storm, the heuristic searching approach was introduced in the process of finding route from source node to destination node. Heuristic function considers the characteristics of MANET (Bandwidth, number of nodes in the given range). If a node S wants to send a packet to D in the flooding method S sends packet to all its neighbor nodes, but in the proposed scheme tries to reduce broadcasting by finding heuristic measures of the neighbors of S. The heuristic measures are evaluated by applying a function to all neighbors. [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]

Ad hoc networking will become a major technology for wireless connectivity beside the multimedia necessity within the next few years. There are too many applications where one-to-many dissemination is necessary. Most of these applications are characterized by the close collaboration teams with requirements for audio, video conferencing and data sharing which QoS parameters such as bandwidth and delay are very critical for them. In this paper, an efficient algorithm named is proposed to improve the route discovery mechanism in MAODV for QoS multicast routes. QoS-MAODV especially can establish a multicast tree with the minimum required bandwidth support and decrease the end-to-end delay between each destination and the source node. It can establish QoS routes with the reserved bandwidth on per chosen flow. To perform accurate resource reservation, we have developed a method for estimating the consumed bandwidth inmulticast trees by extending the methods proposed for unicast routing. The simulation results show that QoS-MAODV protocol produces higher throughput and lower delay in comparison with MAODV protocol. [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]

Interleave division multiple access (IDMA) and orthonogonal frequency division multiplexing - interleave division multiple access (OFDM-IDMA) have been proposed for beyond third generation (B3G) and fourth generation (4G) communication systems. These system are based on iterative multiuser detection (MUD) techniques. The efficiency of these systems is dependent on the generation of efficient user specific interleavers on the basis of which the users are differentiated as compared to signature code sequences in code division multiple access (CDMA). In this paper we discuss the impact of interleaver design on the efficient of IDMA system. [ABSTRACT FROM AUTHOR]

In our paper, we are utilizing the cellular wireless network with high reliability using fixed relay nodes. The size and scope of wireless networks continue to grow with more clients or users, and introduction of innumerable devices and sensors at homes and businesses. These, in conjunction with short and dynamic flow of information, is adding to the spatiotemporal complexity of the network topology and dynamics requiring self organization. [ABSTRACT FROM AUTHOR]

In this paper, a Bluetooth application for controlling an X-Ray Tomograph with a PDA is presented. The new system presents a solution that replaces the old manual keyboard which was not precise and lacked many functionalities. The application is based on a Bluetooth server/client network architecture and was developed in order to give more flexibility to the user than that offered before. It uses the new and advanced capabilities that modern computing offer such as short-range wireless communication to control the movements of the Tomograph's object-manipulator. [ABSTRACT FROM AUTHOR]