4,357 research outputs found

    A Case for Time Slotted Channel Hopping for ICN in the IoT

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    Recent proposals to simplify the operation of the IoT include the use of Information Centric Networking (ICN) paradigms. While this is promising, several challenges remain. In this paper, our core contributions (a) leverage ICN communication patterns to dynamically optimize the use of TSCH (Time Slotted Channel Hopping), a wireless link layer technology increasingly popular in the IoT, and (b) make IoT-style routing adaptive to names, resources, and traffic patterns throughout the network--both without cross-layering. Through a series of experiments on the FIT IoT-LAB interconnecting typical IoT hardware, we find that our approach is fully robust against wireless interference, and almost halves the energy consumed for transmission when compared to CSMA. Most importantly, our adaptive scheduling prevents the time-slotted MAC layer from sacrificing throughput and delay

    Efficient Approximation Algorithms for Multi-Antennae Largest Weight Data Retrieval

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    In a mobile network, wireless data broadcast over mm channels (frequencies) is a powerful means for distributed dissemination of data to clients who access the channels through multi-antennae equipped on their mobile devices. The δ\delta-antennae largest weight data retrieval (δ\deltaALWDR) problem is to compute a schedule for downloading a subset of data items that has a maximum total weight using δ\delta antennae in a given time interval. In this paper, we propose a ratio 1−1e−ϵ1-\frac{1}{e}-\epsilon approximation algorithm for the δ\delta-antennae largest weight data retrieval (δ\deltaALWDR) problem that has the same ratio as the known result but a significantly improved time complexity of O(21ϵ1ϵm7T3.5L)O(2^{\frac{1}{\epsilon}}\frac{1}{\epsilon}m^{7}T^{3.5}L) from O(ϵ3.5m3.5ϵT3.5L)O(\epsilon^{3.5}m^{\frac{3.5}{\epsilon}}T^{3.5}L) when δ=1\delta=1 \cite{lu2014data}. To our knowledge, our algorithm represents the first ratio 1−1e−ϵ1-\frac{1}{e}-\epsilon approximation solution to δ\deltaALWDR for the general case of arbitrary δ\delta. To achieve this, we first give a ratio 1−1e1-\frac{1}{e} algorithm for the γ\gamma-separated δ\deltaALWDR (δ\deltaAγ\gammaLWDR) with runtime O(m7T3.5L)O(m^{7}T^{3.5}L), under the assumption that every data item appears at most once in each segment of δ\deltaAγ\gammaLWDR, for any input of maximum length LL on mm channels in TT time slots. Then, we show that we can retain the same ratio for δ\deltaAγ\gammaLWDR without this assumption at the cost of increased time complexity to O(2γm7T3.5L)O(2^{\gamma}m^{7}T^{3.5}L). This result immediately yields an approximation solution of same ratio and time complexity for δ\deltaALWDR, presenting a significant improvement of the known time complexity of ratio 1−1e−ϵ1-\frac{1}{e}-\epsilon approximation to the problem

    Pervasive Data Access in Wireless and Mobile Computing Environments

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    The rapid advance of wireless and portable computing technology has brought a lot of research interests and momentum to the area of mobile computing. One of the research focus is on pervasive data access. with wireless connections, users can access information at any place at any time. However, various constraints such as limited client capability, limited bandwidth, weak connectivity, and client mobility impose many challenging technical issues. In the past years, tremendous research efforts have been put forth to address the issues related to pervasive data access. A number of interesting research results were reported in the literature. This survey paper reviews important works in two important dimensions of pervasive data access: data broadcast and client caching. In addition, data access techniques aiming at various application requirements (such as time, location, semantics and reliability) are covered

    Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey

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    Wireless sensor networks (WSNs) consist of autonomous and resource-limited devices. The devices cooperate to monitor one or more physical phenomena within an area of interest. WSNs operate as stochastic systems because of randomness in the monitored environments. For long service time and low maintenance cost, WSNs require adaptive and robust methods to address data exchange, topology formulation, resource and power optimization, sensing coverage and object detection, and security challenges. In these problems, sensor nodes are to make optimized decisions from a set of accessible strategies to achieve design goals. This survey reviews numerous applications of the Markov decision process (MDP) framework, a powerful decision-making tool to develop adaptive algorithms and protocols for WSNs. Furthermore, various solution methods are discussed and compared to serve as a guide for using MDPs in WSNs

    Ad-hoc Stream Adaptive Protocol

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    With the growing market of smart-phones, sophisticated applications that do extensive computation are common on mobile platform; and with consumers’ high expectation of technologies to stay connected on the go, academic researchers and industries have been making efforts to find ways to stream multimedia contents to mobile devices. However, the restricted wireless channel bandwidth, unstable nature of wireless channels, and unpredictable nature of mobility, has been the major road block for wireless streaming advance forward. In this paper, various recent studies on mobility and P2P system proposal are explained and analyzed, and propose a new design based on existing P2P systems, aimed to solve the wireless and mobility issues

    Sparse Signal Processing Concepts for Efficient 5G System Design

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    As it becomes increasingly apparent that 4G will not be able to meet the emerging demands of future mobile communication systems, the question what could make up a 5G system, what are the crucial challenges and what are the key drivers is part of intensive, ongoing discussions. Partly due to the advent of compressive sensing, methods that can optimally exploit sparsity in signals have received tremendous attention in recent years. In this paper we will describe a variety of scenarios in which signal sparsity arises naturally in 5G wireless systems. Signal sparsity and the associated rich collection of tools and algorithms will thus be a viable source for innovation in 5G wireless system design. We will discribe applications of this sparse signal processing paradigm in MIMO random access, cloud radio access networks, compressive channel-source network coding, and embedded security. We will also emphasize important open problem that may arise in 5G system design, for which sparsity will potentially play a key role in their solution.Comment: 18 pages, 5 figures, accepted for publication in IEEE Acces
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