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Tie-breaking Can Maximize Fairness without Sacrificing Throughput in D2D-assisted Networks
Get PDFOpportunistic schedulers such as MaxRate and Proportional Fair are known for trading off between throughput and fairness of users in cellular networks. In this paper, we propose a novel solution that integrates opportunistic scheduling design principles and cooperative D2D communication capabilities in order to maximize fairness without sacrificing throughput. Specifically, we develop a mathematical approach and design a smart tie-breaking scheme which maximizes the fairness achieved by the MaxRate scheduler. However, our approach could be applied to improve fairness of any scheduler. In addition, we show that users that cooperatively form D2D clusters benefit from both higher throughput and fairness. Our scheduling scheme is simple to implement, scales linearly with the number of clusters, and is able to double the throughput of Equal Time schedulers and to outperform by 20% or more Proportional Fair schedulers, while providing a user fairness index comparable to or better than Proportional Fair.TRUEpu
An adaptive 5G multiservice and multitenant radio access network architecture
Get PDFThis article provides an overview on objectives and first results of the Horizon 2020 project 5G NOvel Radio Multiservice adaptive network Architecture (5GNORMA). With 5G NORMA, leading players in the mobile ecosystem aim to underpin Europe's leadership position in 5G. The key objective of 5G NORMA is to develop a conceptually novel, adaptive and future-proof 5G mobile network architecture. This architecture will allow for adapting the network to a wide range of service specific requirements, resulting in novel service-aware and context-aware end-to-end function chaining. The technical approach is based on an innovative concept of adaptive (de)composition and allocation of mobile network functions based on end-user requirements and infrastructure capabilities. At the same time, cost savings and faster time to market are to be expected by joint deployment of logically separated multiservice and multitenant networks on common hardware and other physical resources making use of traffic multiplexing gains. In this context architectural enablers such as network function virtualization and software-defined mobile networking will play a key role for introducing the needed flexible resource assignment to logical networks and specific virtual network functions. Copyright © 2016 John Wiley & Sons, Ltd.pu
Tracking the Trackers: Towards Understanding the Mobile Advertising and Tracking Ecosystem
Get PDFThird-party services form an integral part of the mobile ecosystem: they allow app developers to add features such as performance analytics and social network integration, and to monetize their apps by enabling user tracking and targeted ad delivery. At present users, researchers, and regulators all have at best limited understanding of this third-party ecosystem. In this paper we seek to shrink this gap. Using data from users of our ICSI Haystack app we gain a rich view of the mobile ecosystem: we identify and characterize domains associated with mobile advertising and user tracking, thereby taking an important step towards greater transparency. We furthermore outline our steps towards a public catalog and census of analytics services, their behavior, their personal data collection processes, and their use across mobile apps.TRUEpu
Efficient voice and video traffic delivery in IEEE 802.11 WLANs: design, implementation and experimental evaluation
Get PDFWhile the IEEE 802.11 protocol has fostered ubiquitous connectivity for wireless users, it was not originally designed to efficiently handle voice or video traffic, which nowadays accounts for most of the Internet traffic. Voice traffic handling is extremely inefficient in existing WLANs due to the large overhead of the protocol and the time spent in contention. Video multicast streaming is both ineffective and inefficient, as its transmissions lack reliability and use a low Modulation and Coding Scheme (MCS). The more robust, but slower, transmission rates result in the well-known performance anomaly problem that degrades network performance. In this thesis we analyze, design and implement solutions to improve the network performance and efficiency when voice and video traffic are present. We first design and experimentally validate a simple yet very effective scheme (VoIPiggy) to improve the efficiency of WLANs with voice traffic. The key idea of VoIPiggy is to piggyback voice frames onto MAC layer acknowledgments, hereby reducing both the frame overhead and the number of times to access the medium, i.e., the time spent in contention as stations aggregate two frames into a single transmission. To quantify the gains of our proposal, we perform an analysis in terms of capacity and delay. Our experimental and analytical results show a dramatic performance improvement, doubling the number of voice conversations that can be allocated in WLANs. Second, we explore a set of mechanisms included in the 802.11aa standard (namely, Direct Multicast Sequence, Groupcast with Retries Unsolicited Retries and Block Acknowledgment), which allow efficient and robust multicast transmission in WLANs. To that aim, we first perform extensive simulations to understand the trade-offs resulting from using the proposed mechanisms. Our results quantify these trade-offs in terms of robustness, resource consumption and complexity, and provide a set of recommended guidelines for their use according to the network scenario. Finally, we develop the first open source implementation of these mechanisms over commodity hardware. We assess their performance under a variety of real-life scenarios, and outline their effectiveness and efficiency when delivering video traffic. Our results provide key insights on which mechanism results more appropriate for a given scenario, this being specified in terms of number of stations, background traffic and video bandwidth.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Assessing the Implications of Cellular Network Performance on Mobile Content Access
Get PDFMobile applications such as VoIP, (live) gaming, or video streaming have diverse QoS requirements ranging from low delay to high throughput. The optimization of the network quality experienced by end-users requires detailed knowledge of the expected network performance. Also, the achieved service quality is affected by a number of factors, including network operator and available technologies. However, most studies measuring the cellular network do not consider the performance implications of network configuration and management. To this end, this paper reports about an extensive data set of cellular network measurements, focused on analyzing root causes of mobile network performance variability. Measurements conducted on a 4G cellular network in Germany show that management and configuration decisions have a substantial impact on the performance. Specifically, it is observed that the association of mobile devices to a Point of Presence (PoP) within the operator’s network can influence the end-to-end performance by a large extent. Given the collected data, a model predicting the PoP assignment and its resulting RTT leveraging Markov Chain and machine learning approaches is developed. RTT increases of 58% to 73% compared to the optimum performance are observed in more than 57% of the measurements. Measurements of the response and page load times of popular websites lead to similar results, namely a median increase of 40% between the worst and the best performing PoPpu
Filtering Noisy 802.11 Time-of-Flight Ranging Measurements from Commoditized WiFi Radios
Get PDFTime-of-flight (ToF) echo techniques have been recently suggested for ranging mobile devices over WiFi radios. However, these techniques have yielded only moderate accuracy in indoor environments because WiFi ToF measurements suffer from extensive device-related noise which makes it challenging to differentiate between direct path from non-direct path signal components when estimating the ranges. Existing multipath mitigation techniques tend to fail at identifying the direct path when the device-related Gaussian noise is in the same order of magnitude, or larger than the multipath noise. In order to address this challenge, we propose a new method for filtering ranging measurements that is better suited for the inherent large noise as found in WiFi radios. Our technique combines statistical learning and robust statistics in a single
filter. The filter is lightweight in the sense that it does not require specialized hardware, the intervention of the user, or cumbersome on-site manual calibration. This makes our method particularly suitable for indoor localization in largescale deployments using existing legacy WiFi infrastructures. We evaluate our technique for indoor mobile tracking scenarios in multipath environments and, through extensive evaluations across four different testbeds covering areas up to 1000m2, the filter is able to achieve a median 2D positioning error between 2.0 and 3.4 meters.Telematics EngineeringUniversidad Carlos III de Madrid, Spainpu
Internet Computing: Using Reputation to Select Workers from a Pool
Get PDFThe assignment and execution of tasks over the Internet is an inexpensive solution in contrast with supercomputers. We consider an Internet-based Master-Worker task computing approach, such as SETI@home. A master process sends tasks, across the Internet, to worker processors. Workers execute, and report back a result. Unfortunately, the disadvantage of this approach is the unreliable nature of the worker processes. Through different studies, workers have been categorized as either malicious (always report an incorrect result), altruistic (always report a correct result), or rational (report whatever result maximizes their benefit). We develop a reputation-based mechanism that guarantees that, eventually, the master will always be receiving the correct task result. We model the behavior of the rational workers through reinforcement learning, and we present three different reputation types to choose, for each computational round, the most reputable from a pool of workers. As workers are not always available, we enhance our reputation scheme to select the most responsive workers. We prove sufficient conditions for eventual correctness under the different reputation types. Our analysis is complemented by simulations exploring various scenarios. Our simulation results expose interesting trade-offs among the different reputation types, workers availability, and cost.TRUEpu
A Mechanism for Fair Distribution of Resources without Payments
Get PDFWe design a mechanism for Fair and Efficient Distribution of Resources (FEDoR) in the presence of strategic agents. We consider a multiple-instances, Bayesian setting, where in
each round the preference of an agent over the set of resources is a private information. We assume that in each of r rounds n agents are competing for k non-identical indivisible goods, (n > k). In each round the strategic agents declare how much they value receiving any of the goods in the specific round. The agent declaring the highest valuation receives the good with the highest value, the agent with the second highest valuation receives the
second highest valued good, etc. Hence we assume a decision function that assigns goods to agents based on their valuations. The novelty of the mechanism is that no payment
scheme is required to achieve truthfulness in a setting with rational/strategic agents. The FEDoR mechanism takes advantage of the repeated nature of the framework, and through a statistical test is able to punish the misreporting agents and be fair, truthful, and socially
efficient. FEDoR is fair in the sense that, in expectation over the course of the rounds, all agents will receive the same good the same amount of times. FEDoR is an eligible candidate for applications that require fair distribution of resources over time. For example, equal share of bandwidth for nodes through the same point of access. But further on, FEDoR can be applied in less trivial settings like sponsored search, where payment is necessary and can be given in the form of a flat participation fee. FEDoR can be a good candidate in a setting like that to solve the problem of starvation of publicity slots for some advertisers that have a difficult time determining their true valuations. To this extent we perform a comparison with traditional mechanisms applied to sponsored search, presenting the advantage of FEDoR.pu
Your Data in the Eyes of the Beholders: Design of a Unified Data Valuation Portal to Estimate Value of Personal Information from Market Perspective
Get PDFNowadays Internet companies that offer valuable services "for free" are becoming ubiquitous. Users benefiting from these services have to expose their personal information through these services as they utilize them. On the other hand, personal information is becoming a merchandisable commodity, venues that sell personal information by auction are emerging. One of these markets is in the form of advertising systems. Despite being a lucrative business, the hoarding of user personal information by commercial companies is a growing issue primarily because of its non-transparent nature. In this paper we present a data valuation portal that shades light on what kinds of personal information is on market and the financial value of it.TRUEpu
Fair Linking Mechanisms for Resource Allocation with Correlated Player Types
Get PDFResource allocation is one of the most relevant problems in the area of Mechanism Design for computing systems. Devising algorithms capable of providing efficient and fair allocation is the objective of many previous research efforts. Usually, the mechanisms they propose deal with selfishness by introducing utility transfers or payments. Since using payments is undesirable in some contexts, a family of mechanisms without payments is proposed in this paper. These mechanisms extend the Linking Mechanism of Jackson and Sonnenschein introducing a generic concept of fairness with correlated preferences. We prove that these mechanisms have good incentive, fairness, and efficiency properties. To conclude, we provide an algorithm, based on the mechanisms, that could be used in practical computing environments.pu