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Online Scheduling for Delayed Mobile Offloading
"... Abstract—WiFi offloading, where mobile users opportunis-tically obtain data through WiFi rather than through cellular networks, is a promising technique to greatly improve spectrum efficiency and reduce cellular network congestion. We consider a system where the service provider deploys multiple WiF ..."
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Abstract—WiFi offloading, where mobile users opportunis-tically obtain data through WiFi rather than through cellular networks, is a promising technique to greatly improve spectrum efficiency and reduce cellular network congestion. We consider a system where the service provider deploys multiple WiFi hotspots to offload mobile traffic, and study the scheduling policy to maximize the amount of offloaded data. Since the movements of users are unpredictable, we focus on online scheduling policy where APs do not have any knowledge about the users ’ mobility patterns. We study performance of online policies by comparing against the optimal offline policy. We prove that any work-conserving policy is able to offload at least half as much data as the offline policy, and then propose an online policy that can offload (e − 1)/e as much data as the offline policy. We further study the case where the service provider can increase the capacity of WiFi so as to provide guarantees on the amount of offloaded data. We propose a simple online policy and prove that our policy only needs half as much capacity as current mechanism to provide the same performance guarantee. I.
User Recruitment for Mobile Crowdsensing over Opportunistic Networks
"... Abstract—We look into the realization of mobile crowdsensing campaigns that draw on the opportunistic networking paradigm, as practised in delay-tolerant networks but also in the emerging device-to-device communication mode in cellular networks. In particular, we ask how mobile users can be optimall ..."
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Abstract—We look into the realization of mobile crowdsensing campaigns that draw on the opportunistic networking paradigm, as practised in delay-tolerant networks but also in the emerging device-to-device communication mode in cellular networks. In particular, we ask how mobile users can be optimally selected in order to generate the required space-time paths across the network for collecting data from a set of fixed locations. The users hold different roles in these paths, from collecting data with their sensing-enabled devices to relaying them across the network and uploading them to data collection points with Internet connectivity. We first consider scenarios with deterministic node mobility and formulate the selection of users as a minimum-cost set cover problem with a submodular objective function. We then generalize to more realistic settings with uncertainty about the user mobility. A methodology is devised for translating the statistics of individual user mobility to statistics of space-time path formation and feeding them to the set cover problem formulation. We describe practical greedy heuristics for the resulting NP-hard problems and compute their approximation ratios. Our experimentation with real mobility datasets (a) illustrates the multiple tradeoffs between the campaign cost and duration, the bound on the hopcount of space-time paths, and the number of collection points; and (b) provides evidence that in realistic problem instances the heuristics perform much better than what their pessimistic worst-case bounds suggest. I.
Sprinkler: Distributed Content Storage for Just-in-Time Streaming
"... We envision cities where networking infrastructures, such as Wi-Fi access points (AP), will be equipped with storage capabilities. We propose to utilize the storage as a large dis-tributed video cache. If successful, we envision that a child will be able to seamlessly watch a movie in a car, as her ..."
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We envision cities where networking infrastructures, such as Wi-Fi access points (AP), will be equipped with storage capabilities. We propose to utilize the storage as a large dis-tributed video cache. If successful, we envision that a child will be able to seamlessly watch a movie in a car, as her tablet downloads necessary parts of the movie over differ-ent Wi-Fi APs. The key challenge arises from the fact that the mobile tablet would not be able to download the entire movie from any single AP. Nonetheless, we show that the APs could be appropriately populated with video “chunks”, such that the tablet can almost always get the needed chunk, just-in-time for video playback. Our system minimizes repli-cation of video chunks, offering citizens with far greater number of videos to watch. We believe that such a video service could benefit cellular networks, by offloading their traffic to a sizable extent. This paper takes a first step into exploring such a city-wide content distribution service, and addresses one piece of the puzzle – efficient content storage. Categories and Subject Descriptors C.2.1[Network Architecture and Design]: Wireless commu-nication
NETWORKING
"... Mobile devices, such as smartphones, provide a readily available basis for mobile offloading [2] and mobile applica-tions [3]. Given the density of devices in urban scenarios, the key challenge is to discover and connect to devices partici-pating in the same application, i.e., that provide or reques ..."
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Mobile devices, such as smartphones, provide a readily available basis for mobile offloading [2] and mobile applica-tions [3]. Given the density of devices in urban scenarios, the key challenge is to discover and connect to devices partici-pating in the same application, i.e., that provide or request content of interest. However, the network-centric design of 802.11 requires instantiation of and association to a network prior to communication, requiring iterative network associa-tions and subsequent discovery. This is because, device and network discovery can not indicate content or application availability; conversely, content discovery requires a shared network. The associated time and communication overhead of trial-and-error associations thereby renders discovery of the right devices within an application impractical.
The Effective Design of Information Sharing System for Human Networks
"... Abstract:- In recent times, most mobile applications are for information sharing; mobile devices are increasingly becoming the end points of information consuming and gradually fetching end points of information consuming. Motivated by the new demands of application as well as limitations of existin ..."
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Abstract:- In recent times, most mobile applications are for information sharing; mobile devices are increasingly becoming the end points of information consuming and gradually fetching end points of information consuming. Motivated by the new demands of application as well as limitations of existing architecture, we imagine a novel type of energetic networking service known as human networks. A human network design was introduced which a network design that facilitates information is sharing among mobile devices all the way through direct interdevice communication. The system comprises of portable devices that contains wireless communication interfaces. In our work we introduced B-SUB, which is an interest motivated system of information sharing for human networks, a content-based publish or else subscribe that attain infrastructure-less communication among mobile devices. The system employs peer to peer communication prototype in human networks, and allows the entire users exchange their interests throughout random contacts. It is proposed for minute to medium sized networks and composed of several devices controlled in a restricted physical area where inter-device communication occasions are plentiful and includes content representation and pub/sub routing; and employs tag-based content description representation.
1Offloading Cellular Traffic through Opportunistic Communications: Analysis and Optimization
"... Abstract—Offloading traffic through opportunistic communi-cations has been recently proposed as a way to relieve the current overload of cellular networks. Opportunistic communication can occur when mobile device users are (temporarily) in each other’s proximity, such that the devices can establish ..."
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Abstract—Offloading traffic through opportunistic communi-cations has been recently proposed as a way to relieve the current overload of cellular networks. Opportunistic communication can occur when mobile device users are (temporarily) in each other’s proximity, such that the devices can establish a local peer-to-peer connection (e.g., via Bluetooth). Since opportunistic communication is based on the spontaneous mobility of the participants, it is inherently unreliable. This poses a serious challenge to the design of any cellular offloading solutions, that must meet the applications ’ requirements. In this paper, we address this challenge from an optimization analysis perspective, in contrast to the existing heuristic solutions. We first model the dissemination of content (injected through the cellular interface) in an opportunistic network with heterogeneous node mobility. Then, based on this model, we derive the optimal content injection strategy, which minimizes the load of the cellular network while meeting the applications ’ constraints. Finally, we propose an adaptive algorithm based on control theory that implements this optimal strategy without requiring any data on the mobility patterns or the mobile nodes ’ contact rates. The proposed approach is extensively evaluated with both a heterogeneous mobility model as well as real-world contact traces, showing that it substantially outperforms previous approaches proposed in the literature. I.
Flooding Data in a Cell: Is Cellular Multicast Better than Device-to-Device Communications?
"... A natural method to disseminate popular data on cellular networks is to use multicast. Despite having clear advantages over unicast, multicast does not offer any kind of reliability and could result costly in terms of cellular resources in the case at least one of the destinations is at the edge of ..."
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A natural method to disseminate popular data on cellular networks is to use multicast. Despite having clear advantages over unicast, multicast does not offer any kind of reliability and could result costly in terms of cellular resources in the case at least one of the destinations is at the edge of the cell (i.e., with poor radio conditions). In this paper, we show that, when content dissemination tolerates some delay, providing device-to-device communications over an orthogonal channel increases the efficiency of multicast, concurring also to offload part of the traffic from the infrastructure. Our evaluation simulates an LTE macro-cell with mobile receivers and reveals that the joint utilization of device-to-device communications and multicasting brings significant resource savings while increasing the cellular throughput.
Push-and-Track: Saving Infrastructure Bandwidth Through Opportunistic Forwarding
"... Major wireless operators are nowadays facing network capacity issues in striving to meet the growing demands of mobile users. At the same time, 3G-enabled devices increasingly benefit from ad hoc radio connectivity (e.g., WiFi). In this context of hybrid connectivity, we propose Push-and-track, a co ..."
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Major wireless operators are nowadays facing network capacity issues in striving to meet the growing demands of mobile users. At the same time, 3G-enabled devices increasingly benefit from ad hoc radio connectivity (e.g., WiFi). In this context of hybrid connectivity, we propose Push-and-track, a content dissemina-tion framework that harnesses ad hoc communication opportunities to minimize the load on the wireless infrastructure while guaranteeing tight delivery delays. It achieves this through a control loop that collects user-sent acknowledgements to determine if new copies need to be re-injected into the network through the 3G interface. Push-and-Track is flexible and can be applied to a variety of scenarios, including periodic message flooding and floating data. For the former, this paper examines multiple strategies to determine how many copies of the content should be injected, when, and to whom; for the latter, it examines the achievable offload ratio depending on the freshness constraints. The short delay-tolerance of common content, such as news or road traffic updates, make them suitable for such a system. Use cases with a long delay-tolerance, such as software updates, are an even better fit. Based on a realistic large-scale vehicular dataset from the city of Bologna composed of more than 10,000 vehicles, we demonstrate that Push-and-Track consistently meets its delivery objectives while reducing the use of the 3G network by about 90%.
