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Wireless Sensor Networks (WSNs) have attracted significant research interest in recent years because of their suitability to a wide range of real world applications. The envisioned Internet Protocol (IP) support for WSNs requires interoperability with existing management solutions, like Simple Network Management Protocol (SNMP), in order to provide remote management functionality and assure the correct...
Quality of service (QoS) provisioning generally assumes more than one QoS measure which implies that QoS routing can be categorized as an instance of routing subject to multiple constraints: delay-jitter, bandwidth, cost, etc. We study the problem of constructing multicast trees to meet the QoS requirements of real-time interactive applications where it is necessary to provide bounded delays and bounded...
Delay Tolerant Network (DTN) is evolved from Mobile Adhoc Network, MaNet. It is sparse and intermittently connected mobile adhoc network where reliable communication and end-to-end connectivity is not available for message transmission. The end to end connectivity is not ensured in Delay Tolerant Network. Only high latency applications are used in DTN. Latency may be in hours or days. The store and...
In connection with the nonlinear dynamic characteristics shown from the performance of fault rotating mechanical system, based on the research and analysis, correlation dimension and complexity can be used to characterize the system state of motion. The authors propose the analysis method of correlation dimension and complexity to the signal feature of mechanical fault. Using theory of phase space...
To improve the efficiency and the topology mismatch problem of P2P overlay network, a new method of topology construction, CLSP2P, was introduced. The topology construction of CLSP2P not only consideration the physical location of nodes, but also consideration the semantic information of nodes: Nodes in CLSP2P were first organized as autonomous domain based on their physical location, then the nodes...
This paper presents a new data transmission protocol in Delay Tolerant Mobile Wireless Sensor Networks, which divides the data transmission process into two phases: data reception phase and data forwarding phase, mainly fulfilling through analyzing the state of mobile nodes and using Hand up mechanism. Simulation result shows that, through the implementation of two phases, we can obtain a higher message...
An improved Vegas scheme is proposed with a measure of congestion control as average round trip time rather than round trip time. It enhanced the prevention of congestion control. Simulation results demonstrate in some scenario that the instantaneous queue length improved the stability and decreased response time.
In present paper, the time-delayed feedback is coupled with a ratio-dependent predator-prey model of Holling □ type. This predator-prey system can be seen as a human-controlled biological system. Regarding the delay as parameter, we investigate the existence of local Hopf bifurcations. By using the Hassard method and the center manifold argument, we derive the explicit formulas determining the stability,...
Rich media application enables plenty of interactive, information-rich services to enhance end user's viewing experience. In current standards released for such service, only one rendering space is defined to handle multiple types of content belonging to the same service. However, a new trend is to assign more than one terminal device to render rich media application in a cooperative way inside a...
In this paper, we propose a method for reconstructing the output of an Oversampled Filter Bank (OFB) when instantaneous erasures happen in the sub-band domain. Instantaneous erasure is defined as a situation where the erasure pattern changes in each time instance. This definition differs from the type of erasure usually defined in literature, where e erasures means that e channels of the OFB are off...
Unlike traditional routing schemes that route all traffic along a single path, multipath routing strategies split the traffic among several paths in order to ease congestion. It has been widely recognized that multipath routing can be fundamentally more efficient than the traditional approach of routing along single paths. aiming at the increasing network traffic and the deficity that the former Ant...
Network coding is known to provide increased throughput and reduced delay for communications over networks. In this paper we propose a peer-to-peer video streaming system that exploits network coding in order to achieve low start-up delay, high streaming rate, and high resiliency to peers' dynamics. In particular, we introduce the concept of random multicast trees as overlay topology. This topology...
In this paper, we investigate the training problem of wireless local area networks (WLANs) with downlink multi-user multiple input multiple output (DL MU MIMO) capability. We extend the 802.11 MAC protocol and propose a few training protocols at the MAC layer to support DL MU MIMO. We provide a capacity analysis based on measurement results from an 802.11n systems, evaluate the overhead of these training...
Perfect Space-Time Codes (STC) are full-rate, full-diversity codes originally proposed for Multiple Input Multiple Output (MIMO) systems. Based on Cyclic Division Algebras (CDA), they have non-vanishing determinants and hence achieve the Diversity-Multiplexing Tradeoff (DMT). In addition, these codes have led to optimal distributed Space-Time Codes when applied in cooperative networks under the assumption...
We derive closed form expressions for the second-order statistics of the spectral power gain of wide-band microwave indoor channels. We obtain our results within a framework general enough to be compatible with several popular channel models, such as those proposed by the IEEE 802.15.3a task group, as well as the Saleh-Valenzuela channel model. As all these models, our channel description is based...
Fourth Generation Networks will invariably adopt MIMO-OFDMA techniques, in order to cope with increased data rate demands and improved Quality of Service (QoS) requirements. OFDMA is a popular multiple access candidate, since it facilitates multi-user diversity by enabling two dimensional multiple access, in time and frequency domains. Random Beamforming enables exploitation of spatial multi-user...
In this paper, we present a novel rateless code which outperforms LT-code, since it is adapted for network coding. To reduce the delay incurred at the intermediate nodes because of decoding and re-encoding, we design and analyze a novel degree distribution which we call Switched Distribution. This distribution increases the delivery ratio at the decoder even when few encoded symbols are received....
Contention-based forwarding (CBF) has proven to achieve a good performance in routing in mobile and vehicular ad hoc networks. CBF's main advantage is that it does not require the knowledge about the local neighborhood, eliminating, therefore, the periodic beacon exchange that causes degradation in the network performance, especially when the density of the neighborhood is high. On the other hand,...
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...
In order to reduce MAP overhead for periodic small-sized services such as voice over IP (VoIP) service, a persistent scheduling scheme has been proposed in IEEE 802.16e/m. Although this persistent scheduling scheme is designed for periodic services, we propose to adopt the persistent scheduling for non-periodic real-time services with small-sized packets by considering the advantage of MAP overhead...
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