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In recent years, there have been significant efforts related to vehicle-to-vehicle (V2V) communication. The major demand of the V2V communication was originally from safety-related applications; and the possible application areas including communication support for auto-navigation have increased. Local Peer Group (LPG) is a partitioning structure to promote quick deliveries of time- sensitive information...
We propose a efficient semi-distributed resource allocation scheme for OFDMA relay-enhanced downlink systems. Firstly, an adaptive subframe partitioning (ASP) algorithm that considers user's queue length and achievable data rate is used by base station to assign resources to relay stations. Regarding the slot allocation, we suggest two ways to extend conventional single-hop scheduling algorithms into...
This paper proposes a three-dimensional (3-D) scattering model for multiple-input multiple-output (MIMO) land mobile stratospheric multipath-fading channels. Analytical and closed-form expressions for the spatial and temporal correlation functions between two arbitrary sub-channels are derived, assuming non-isotropic or isotropic scattering environments. This model can be used to estimate the required...
The next generation of wireless networks (e.g.,) will use multiple techniques to improve channel spectral efficiencies. In this paper we focus on one such technique, beamforming, in the downlink channel. In each sector a number of fixed beams are used to serve users. For each frame the scheduler chooses a beam and then schedules one or more mobiles that lie within that beam. Since the basestation's...
In order to support real-time and bandwidth demanding applications, the IEEE 802.16 standard is expected to provide quality of service (QoS). Although the standard defines a QoS signaling framework and five service levels, scheduling mechanisms for this network are unspecified. In this paper, we propose a scheduling scheme for the uplink traffic which is fully standard-compliant and can be easily...
This paper considers the problem of subcarrier scheduling in the downlink of multicell OFDMA networks. It proposes a dynamic fractional frequency reuse cell architecture that partitions subcarriers into two groups. One is reused in the whole cell area whereas the other is partitioned into sectors and used orthogonally. The proposed architecture allows dynamic allocation of users to the group of subcarriers...
We introduce the concept of cognitive wireless mesh network, named CogMesh, in order to meet the future needs of ubiquitous wireless communications. CogMesh is not a concept that simply applies cognitive functionalities into traditional wireless mesh networks. Instead, it aims to enable a uniform service platform by seamlessly integrating heterogenous wireless networks through the utilization of advanced...
Mesh router (MR) placement is one of the fundamental issues that need to be carefully addressed to provide mesh clients with satisfactory performance in a wireless mesh network (WMN). This paper proposes a virtual force based MR placement algorithm (VFPlace) which is scalable and self- adaptive. Given a certain number of MRs, VFPlace targets to determine the positions of these MRs to maximize their...
Protocol designs in wireless sensor networks (WSNs) have to consider many constraints such as limited power and computing capacity. We propose an end-to-end adaptive confidentiality mechanism (ACM), which significantly reduces the risk of adversary capturing aggregated messages leaving a cluster head while meeting these rigid resource constraints. ACM divides an encrypted message into several segments...
With recent advances enabling the deployment of large-scale collaborative Wireless Sensor Networks, numerous factors point to the need for sensor network deployments where subsets of nodes cooperate on specific tasks or networks supporting multiple applications. Virtual Sensor Networks (VSNs) is a concept to provide such support for the formation, usage, adaptation, and maintenance of subsets of sensors...
In this paper, the suitability of 5.8 GHz FMCW localisation schemes using chip-integrated radio transmitters is shown for the application of wireless sensor networks and one possible implementation is proposed. The synthesizer concept is based on a fractional-n PLL and was partly realized in an integrated circuit within the RESOLUTION EC-funded project. The basics of FMCW-TDOA radiolocation are described...
A mobile ad hoc network is an infrastructureless multi-hop system of wireless autonomous mobile nodes. Reactive routing protocols like ad hoc on demand distance vector routing (AODV) and dynamic source routing (DSR) are appropriate for mobile environments, because they cope quickly with topological changes. Lately cooperative-transmission-based routing protocols have been proposed to further save...
Communication networks form the basis for supporting various ubiquitous and pervasive grid applications, therefore network service discovery, selection, and composition play a significant role in ubiquitous and pervasive grids. Due to the heterogeneity of networking systems in ubiquitous and pervasive computing environments, network service description and discovery in ubiquitous and pervasive grids...
Ad hoc user task composition involves automatic matching and selection of services across various devices in the pervasive environment. Existing service composition approaches mostly do not consider network heterogeneity or devices' capabilities simultaneously. This limits the composition mechanism, as not all the devices will be able to use the same set of network protocols. The user preferences...
Service discovery is a process that enables networked entities to be aware of available services and to obtain the necessary means to access the services. Within a service discovery architecture, the way the service data are gathered, called service registration, influences the performance of the system. In particular, it affects the consistency and query response time. Most of the existing architectures...
IPTV promises to be within the spectrum of services offered in the future Internet. In cooperative IPTV, clients' resources are typically used to build a scalable system to distribute TV content. One of the major challenges of this approach is to reach the same quality of service of traditional television and commercial IPTV by employing only best effort network layer services. This paper proposes...
This paper analyzes the performance of a MAC scheme for low-rate wireless sensor networks that makes use of distributed queues to improve radio channel utilization. Analytical values first for the throughput performance, and later for the energy consumption are derived as a function of the system parameters. The obtained results show that the proposed scheme outperforms IEEE 802.15.4 MAC in terms...
Voice over Internet protocol (VOIP) technology has been widely adopted in communication middleware systems that allow service providers to construct web based applications, such as Web conference systems (WebEx, Gotomeeting), IP based call centers and Web chatting. VOIP is vulnerable to network congestion if too many users access the Web service based VOIP at the same time, especially the services...
Wireless sensor networks are becoming increasingly popular and are widely used in many applications. Sensors can be used for environment and habitat monitoring, healthcare applications, home automation and traffic control. Many of these applications require sensors with speech recording/transmitting capabilities. In such cases, bandwidth usage could be significantly reduced if speech is transmitted...
In traditional Web applications, user interface and interaction flows are controlled by software programs deployed on the server. These server side software programs are designed and implemented by software programmers, with no or very limited control provided to the end user.Although portal server technology and some JavaScript based solutions try to address this issue by offering some degree of...
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