MobiCom '20: The 26th Annual International Conference on Mobile Computing and Networking, London, United Kingdom, September 21-25, 2020. ACM 【DBLP Link】
【Paper Link】 【Pages】:1:1-1:14
【Authors】: Xuefeng Liu ; Tianye Yang ; Shaojie Tang ; Peng Guo ; Jianwei Niu
【Abstract】: Pyroelectric infrared (PIR) sensors are considered to be promising devices for device-free localization due to its advantages of low cost, energy efficiency, and the immunity from multi-path fading. However, most of the existing PIR-based localization systems only utilize the binary information of PIR sensors and therefore require a large number of carefully deployed PIR sensors. A few works directly map the raw data of PIR sensors to one's location using machine learning approaches. However, these data-driven approaches require abundant training data and suffer from environmental change. In this paper, we propose PIRATES, a PIR-based device-free localization system based on the raw data of PIR sensors. The key of PIRATES is to extract a new type of location information called azimuth change. The extraction of the azimuth change relies on the physical properties of PIR sensors. Therefore, no abundant training data are needed and the system is robust to environmental change. Through experiments, we demonstrate that PIRATES can achieve higher localization accuracy than the state-of-the-art approaches. In addition, the information of the azimuth change can be easily incorporated with other information of PIR signals (e.g. amplitude) to improve the localization accuracy.
【Keywords】: Human-centered computing; Ubiquitous and mobile computing
【Paper Link】 【Pages】:2:1-2:14
【Authors】: Vaibhav Singh ; Susnata Mondal ; Akshay Gadre ; Milind Srivastava ; Jeyanandh Paramesh ; Swarun Kumar
【Abstract】: mm-Wave has emerged as an attractive high-speed wireless communication paradigm owing to the high available bandwidth at mm-wave frequencies. Full-Duplex has the potential to double the available capacity in the mm-wave bands by enabling simultaneous radio transmission and reception. While full-duplex has been extensively studied in sub-6 GHz bands, this paper exposes the unique challenges in porting this capability to mm-wave frequencies.
【Keywords】: Computer systems organization; Embedded and cyber-physical systems; Hardware; Integrated circuits; Networks; Network components
【Paper Link】 【Pages】:3:1-3:13
【Authors】: Mohammad Rostami ; Karthik Sundaresan ; Eugene Chai ; Sampath Rangarajan ; Deepak Ganesan
【Abstract】: The recent innovation of frequency-shifted (FS) backscatter allows for backscattering with commodity devices, which are inherently half-duplex. However, their reliance on oscillators for generating the frequency-shifting signal on the tag, forces them to incur the transient phase of the oscillator before steady-state operation. We show how the oscillator's transient phase can pose a fundamental limitation for battery-less tags, resulting in significantly low bandwidth efficiencies, thereby limiting their practical usage.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Wireless devices; Networks; Network types; Home networks
【Paper Link】 【Pages】:4:1-4:14
【Authors】: Juheon Yi ; Sunghyun Choi ; Youngki Lee
【Abstract】: We present EagleEye, an AR-based system that identifies missing person (or people) in large, crowded urban spaces. Designing EagleEye involves critical technical challenges for both accuracy and latency. Firstly, despite recent advances in Deep Neural Network (DNN)-based face identification, we observe that state-of-the-art models fail to accurately identify Low-Resolution (LR) faces. Accordingly, we design a novel Identity Clarification Network to recover missing details in the LR faces, which enhances true positives by 78% with only 14% false positives. Furthermore, designing EagleEye involves unique challenges compared to recent continuous mobile vision systems in that it requires running a series of complex DNNs multiple times on a high-resolution image. To tackle the challenge, we develop Content-Adaptive Parallel Execution to optimize complex multi-DNN face identification pipeline execution latency using heterogeneous processors on mobile and cloud. Our results show that EagleEye achieves 9.07X faster latency compared to naive execution, with only 108 KBytes of data offloaded.
【Keywords】: Computer systems organization; Real-time systems; Real-time system architecture; Human-centered computing; Ubiquitous and mobile computing
【Paper Link】 【Pages】:5:1-5:14
【Authors】: Song Wang ; Jingqi Huang ; Xinyu Zhang ; Hyoil Kim ; Sujit Dey
【Abstract】: Millimeter-wave (mmWave) networks are conventionally considered to bear a fundamental coverage limitation, due to the directional beams and limited field-of-view (FoV) of the phased array antennas. In this paper, we explore an array of phased arrays (APA) architecture, which aggregates co-located phased arrays with complementary FoVs to approximate WiFi-like omni-directional coverage. We found that straightforwardly activating all the arrays may even hamper network performance. To fully exploit the APA's potential, we propose X-Array, which jointly selects the arrays and beams, and applies a dynamic co-phasing mechanism to ensure different arrays' signals enhance each other. X-Array also incorporates a link recovery mechanism to identify alternative arrays/beams that can efficiently recover the link from outage. We have implemented X-Array on a commodity 802.11ad APA radio. Our experiments demonstrate that X-Array can approach omni-directional coverage and maintain high performance in spite of link dynamics.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Wireless devices; Emerging technologies; Analysis and design of emerging devices and systems; Networks; Network performance evaluation; Network experimentation; Network properties; Network mobility
【Paper Link】 【Pages】:6:1-6:13
【Authors】: Purui Wang ; Lilei Feng ; Guojun Chen ; Chenren Xu ; Yue Wu ; Kenuo Xu ; Guobin Shen ; Kuntai Du ; Gang Huang ; Xuanzhe Liu
【Abstract】: Conventional road signs convey very concise and static visual information to human drivers, and bear retroreflective coating for better visibility at night. This paper introduces RetroI2V - a novel infrastructure-to-vehicle (I2V) communication and networking system that renovates conventional road signs to convey additional and dynamic information to vehicles while keeping intact their original functionality. In particular, RetroI2V exploits the retroreflective coating of road signs and establishes visible light backscattering communication (VLBC), and further coordinates multiple concurrent VLBC sessions among road signs and approaching vehicles. RetroI2V features a suite of novel VLBC designs including late-polarization, complementary optical signaling and polarization-based differential reception which are crucial to avoid flickering and achieve long VLBC range, as well as a decentralized MAC protocol that make practical multiple access in highly mobile and transient I2V settings. Experimental results from our prototyped system show that RetroI2V supports up to 101 m communication range and efficient multiple access at scale.
【Keywords】: Computer systems organization; Embedded and cyber-physical systems; Embedded systems; Hardware; Communication hardware, interfaces and storage; Wireless devices
【Paper Link】 【Pages】:7:1-7:14
【Authors】: Sheng Shen ; Daguan Chen ; Yu-Lin Wei ; Zhijian Yang ; Romit Roy Choudhury
【Abstract】: Voice assistants such as Amazon Echo (Alexa) and Google Home use microphone arrays to estimate the angle of arrival (AoA) of the human voice. This paper focuses on adding user localization as a new capability to voice assistants. For any voice command, we desire Alexa to be able to localize the user inside the home. The core challenge is two-fold: (1) accurately estimating the AoAs of multipath echoes without the knowledge of the source signal, and (2) tracing back these AoAs to reverse triangulate the user's location.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Signal processing systems; Human-centered computing; Ubiquitous and mobile computing; Information systems; Information systems applications; Spatial-temporal systems; Location based services
【Paper Link】 【Pages】:8:1-8:14
【Authors】: Yu-Han Lu ; Chi-Yu Li ; Yao-Yu Li ; Sandy Hsin-Yu Hsiao ; Tian Xie ; Guan-Hua Tu ; Wei-Xun Chen
【Abstract】: IMS (IP Multimedia Subsystem) is an essential framework for providing 4G/5G multimedia services. It has been deployed worldwide to support two call services: VoLTE (Voice over LTE) and VoWi-Fi (Voice over Wi-Fi). VoWi-Fi enables telephony calls over the Wi-Fi network to complement VoLTE. In this work, we uncover that the VoWi-Fi signaling session can be hijacked to maliciously manipulate the IMS call operation. An adversary can easily make ghost calls to launch a stealthy call DoS (Denial of Service) attack against specific cellular users. Only phone numbers, but not any malware or network information, are required from the victims. This sophisticated attack harnesses a design defect of the IMS call state machine, but not simply flooding or a crash trigger. To stealthily detect attackable phones at run time, we exploit a vulnerability of the 4G network infrastructure, call information leakage, which we explore using machine learning. We validate these vulnerabilities in operational 4G networks of 4 top-tier carriers across Asia and North America countries with 7 phone brands. Our result shows that the call DoS attack can prevent the victims from receiving incoming calls up to 99.0% time without user awareness. We finally propose and evaluate recommended solutions.
【Keywords】: Networks; Network properties; Network security; Mobile and wireless security; Network protocols; Application layer protocols; Security and privacy; Systems security; Denial-of-service attacks
【Paper Link】 【Pages】:9:1-9:13
【Authors】: Sujay Narayana ; R. Venkatesha Prasad ; Vijay S. Rao ; Luca Mottola ; T. Venkata Prabhakar
【Abstract】: Global Positioning System is a widely adopted localization technique. With the increasing demand for small satellites, the need for a low-power GPS for satellites is also increasing. To enable many state-of-the-art applications, the exact position of the satellites is necessary. However, building low-power GPS receivers which operate in low earth orbit pose significant challenges. This is mainly due to the high speed (~7.8 km/s) of small satellites. While duty-cycling the receiver is a possible solution, the high relative Doppler shift between the GPS satellites and the small satellite contributes to the increase in Time To First Fix (TTFF), thus increasing the energy consumption. Further, if the GPS receiver is tumbling along with the small satellite on which it is mounted, longer TTFF may lead to no GPS fix due to disorientation of the receiver antenna. In this paper, we elucidate the design of a low-cost, low-power GPS receiver for small satellite applications. We also propose an energy optimization algorithm called F3to improve the TTFF which is the main contributor to the energy consumption during cold start. With simulations and in-orbit evaluation from a launched nanosatellite with our μGPS and high-end GPS simulators, we show that up to 96.16% of energy savings (consuming only ~ 1/25th energy compared to the state of the art) can be achieved using our algorithm without compromising much (~10 m) on the navigation accuracy. The TTFF achieved is at most 33 s.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Sensor applications and deployments; Theory of computation; Design and analysis of algorithms; Mathematical optimization
【Paper Link】 【Pages】:10:1-10:14
【Authors】: Manideep Dunna ; Chi Zhang ; Daniel F. Sievenpiper ; Dinesh Bharadia
【Abstract】: In the last decade, the bandwidth expansion and MIMO spatial multiplexing have promised to increase data throughput by orders of magnitude. However, we are yet to enjoy such improvement in real-world environments, as they lack rich scattering and preclude effective MIMO spatial multiplexing. In this paper, we present ScatterMIMO, which uses smart surface to increase the scattering in the environment, to provide MIMO spatial multiplexing gain. Specifically, smart surface pairs up with a wireless transmitter device say an active AP and re-radiates the same amount of power as any active access point (AP), thereby creating virtual passive APs. ScatterMIMO avoids the synchronization, interference, and power requirements of conventional distributed MIMO systems by leveraging virtual passive APs, allowing its smart surface to provide spatial multiplexing gain, which can be deployed at a very low cost. We show that with optimal placement, these virtual APs can provide signals to their clients with power comparable to real active APs, and can increase the coverage of an AP. Furthermore, we design algorithms to optimize ScatterMIMO's smart surface for each client with minimal measurement overhead and to overcome random per-packet phase offsets during the measurement. Our evaluations show that with commercial off-the-shelf MIMO WiFi (11ac) AP and unmodified clients, ScatterMIMO provides a median throughput improvement of 2 X over the active AP alone.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Wireless devices; Networks; Network components; Physical links; Network types; Wireless access networks; Wireless local area networks
【Paper Link】 【Pages】:11:1-11:13
【Authors】: Bo Han ; Yu Liu ; Feng Qian
【Abstract】: In this paper, we perform a first comprehensive study of mobile volumetric video streaming. Volumetric videos are truly 3D, allowing six degrees of freedom (6DoF) movement for their viewers during playback. Such flexibility enables numerous applications in entertainment, healthcare, education, etc. However, volumetric video streaming is extremely bandwidth-intensive. We conduct a detailed investigation of each of the following aspects for point cloud streaming (a popular volumetric data format): encoding, decoding, segmentation, viewport movement patterns, and viewport prediction. Motivated by the observations from the above study, we propose ViVo, which is to the best of our knowledge the first practical mobile volumetric video streaming system with three visibility-aware optimizations. ViVo judiciously determines the video content to fetch based on how, what and where a viewer perceives for reducing bandwidth consumption of volumetric video streaming. Our evaluations over real wireless networks (including commercial 5G), mobile devices and users indicate that ViVo can save on average 40% of data usage (up to 80%) with virtually no drop in visual quality.
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【Paper Link】 【Pages】:12:1-12:14
【Authors】: Hanbin Zhang ; Gabriel Guo ; Chen Song ; Chenhan Xu ; Kevin Yiu-Wah Cheung ; Jasleen Alexis ; Huining Li ; Dongmei Li ; Kun Wang ; Wenyao Xu
【Abstract】: Drug effectiveness management is a complicated and challenging task in chronic diseases, like Parkinson's Disease (PD). Drug effectiveness control is not only linked to personal out-of-pocket cost but also affecting the quality of life among patients with chronic symptoms. In the current practice, although that health and medical professionals still play a key role in the personalized treatment plan, the critical decision on drug selection falls upon the individual report when patients call in or visit the clinics. Unfortunately, most of the patients with chronic diseases either fail to report their day-to-day symptoms or have a limited access to medical resources due to economic constraints. In this paper, we present PDLens, a first smartphone-based system to detect drug effectiveness among Parkinson's in daily life. Specifically, PDLens can extract digital behavioral markers related to PD drug responses from everyday activities, including phone calls, standing, and walking. PDLens models the PD symptom severity on drug treatment and detects the change of severity scores before and after drug intake. A ranking-based multi-view deep neural network is developed to decide the drug effectiveness upon the symptom severity changes. To validate the performance of PDLens, we conduct a pilot study with 81 PD patients and monitor their smartphone activities and severity changes over 33693 drug intake events across six (6) months. Compared with the standard clinical drug effectiveness test developed by Motor Disorder Society, results reveal that PDLens is a promising tool to facilitate drug effectiveness detection among PD patients in their daily lives.
【Keywords】: Human-centered computing; Ubiquitous and mobile computing
【Paper Link】 【Pages】:13:1-13:13
【Authors】: Gaoyang Guan ; Borui Li ; Yi Gao ; Yuxuan Zhang ; Jiajun Bu ; Wei Dong
【Abstract】: The recent years have witnessed the rapid growth of IoT (Internet of Things) applications. A typical IoT application usually consists of three essential parts: the device side, the cloud side, and the client side. The development of a complete IoT application is very difficult for non-expert developers because it involves drastically different technologies and complex interactions between different sides. Unlike traditional IoT development platforms which use separate approaches for these three sides, we present TinyLink 2.0, an integrated IoT development approach with a single coherent language. It achieves high expressiveness for diverse IoT applications by an enhanced IFTTT rule design and a virtual sensor mechanism which helps developers express application logic with machine learning. Moreover, TinyLink 2.0 optimizes the IoT application performance by using both static and dynamic optimizers, especially for resource-constrained IoT devices. We implement TinyLink 2.0 and evaluate it with eight case studies, a user study, and a detailed evaluation of the proposed programming language as well as the performance optimizers. Results show that TinyLink 2.0 can speed up IoT development significantly compared with existing approaches from both industry and academia, while still achieving high expressiveness.
【Keywords】: Computer systems organization; Embedded and cyber-physical systems; Networks; Network types; Cyber-physical networks
【Paper Link】 【Pages】:14:1-14:13
【Authors】: Dipankar Raychaudhuri ; Ivan Seskar ; Gil Zussman ; Thanasis Korakis ; Dan Kilper ; Tingjun Chen ; Jakub Kolodziejski ; Michael Sherman ; Zoran Kostic ; Xiaoxiong Gu ; Harish Krishnaswamy ; Sumit Maheshwari ; Panagiotis Skrimponis ; Craig Gutterman
【Abstract】: This paper focuses on COSMOS - Cloud enhanced Open Software defined MObile wireless testbed for city-Scale deployment. The COSMOS testbed is being deployed in West Harlem (New York City) as part of the NSF Platforms for Advanced Wireless Research (PAWR) program. It will enable researchers to explore the technology "sweet spot" of ultra-high bandwidth and ultra-low latency in the most demanding real-world environment. We describe the testbed's architecture, the design and deployment challenges, and the experience gained during the design and pilot deployment. Specifically, we describe COSMOS' computing and network architectures, the critical building blocks, and its programmability at different layers. The building blocks include software-defined radios, 28 GHz millimeter-wave phased array modules, optical transport network, core and edge cloud, and control and management software. We describe COSMOS' deployment phases in a dense urban environment, the research areas that could be studied in the testbed, and specific example experiments. Finally, we discuss our experience with using COSMOS as an educational tool.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Wireless devices; Networks; Network architectures; Network components; Wireless access points, base stations and infrastructure; Network performance evaluation; Network experimentation; Network types; Wireless access networks
【Paper Link】 【Pages】:15:1-15:14
【Authors】: Renjie Zhao ; Timothy Woodford ; Teng Wei ; Kun Qian ; Xinyu Zhang
【Abstract】: Millimeter-wave (mmWave) technologies represent a cornerstone for emerging wireless network infrastructure, and for RF sensing systems in security, health, and automotive domains. Through a MIMO array of phased arrays with hundreds of antenna elements, mmWave can boost wireless bit-rates to 100+ Gbps, and potentially achieve near-vision sensing resolution. However, the lack of an experimental platform has been impeding research in this field. This paper fills the gap with M3 (M-Cube), the first mmWave massive MIMO software radio. M3 features a fully reconfigurable array of phased arrays, with up to 8 RF chains and 288 antenna elements. Despite the orders of magnitude larger antenna arrays, its cost is orders of magnitude lower, even when compared with state-of-the-art single RF chain mmWave software radios. The key design principle behind M3 is to hijack a low-cost commodity 802.11ad radio, separate the control path and data path inside, regenerate the phased array control signals, and recreate the data signals using a programmable baseband. Extensive experiments have demonstrated the effectiveness of the M3 design, and its usefulness for research in mmWave massive MIMO communication and sensing.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Signal processing systems; Wireless devices; Networks; Network architectures; Programming interfaces
【Paper Link】 【Pages】:16:1-16:10
【Authors】: Diego Perino ; Xiaoyuan Yang ; Joan Serrà ; Andra Lutu ; Ilias Leontiadis
【Abstract】: The Internet Para Todos program is working to provide sustainable mobile broadband to 100 M unconnected people in Latin America. In this paper we present our commercial deployment in thousands remote small communities and describe the unique experience of maintaining this infrastructure. We describe the challenges related to managing operations containing the cost in these extreme geographical conditions. We also analyze operational data to understand outage patterns and present typical operational issues in this unique remote community environment. Finally, we present an extension of the operations support system (OSS) leveraging advanced analytics and machine learning with the goal of optimizing network maintenance while reducing costs.
【Keywords】: Networks; Network architectures; Network design principles; Network performance evaluation; Network measurement; Network services; Network management
【Paper Link】 【Pages】:17:1-17:14
【Authors】: Roshan Sai Ayyalasomayajula ; Aditya Arun ; Chenfeng Wu ; Sanatan Sharma ; Abhishek Rajkumar Sethi ; Deepak Vasisht ; Dinesh Bharadia
【Abstract】: Location services, fundamentally, rely on two components: a mapping system and a positioning system. The mapping system provides the physical map of the space, and the positioning system identifies the position within the map. Outdoor location services have thrived over the last couple of decades because of well-established platforms for both these components (e.g. Google Maps for mapping, and GPS for positioning). In contrast, indoor location services haven't caught up because of the lack of reliable mapping and positioning frameworks. Wi-Fi positioning lacks maps and is also prone to environmental errors. In this paper, we present DLoc, a Deep Learning based wireless localization algorithm that can overcome traditional limitations of RF-based localization approaches (like multipath, occlusions, etc.). We augment DLoc with an automated mapping platform, MapFind. MapFind constructs location-tagged maps of the environment and generates training data for DLoc. Together, they allow off-the-shelf Wi-Fi devices like smartphones to access a map of the environment and to estimate their position with respect to that map. During our evaluation, MapFind has collected location estimates of over 105 thousand points under 8 different scenarios with varying furniture positions and people motion across two different spaces covering 2000 sq. Ft. DLoc outperforms state-of-the-art methods in Wi-Fi-based localization by 80% (median & 90th percentile) across the two different spaces.
【Keywords】: Computing methodologies; Artificial intelligence; Planning and scheduling; Robotic planning; Machine learning; Learning paradigms; Supervised learning; Information systems; Information systems applications; Spatial-temporal systems; Sensor networks; Networks; Network services; Location based services
【Paper Link】 【Pages】:18:1-18:13
【Authors】: Yasaman Ghasempour ; Chia-Yi Yeh ; Rabi Shrestha ; Daniel M. Mittleman ; Edward W. Knightly
【Abstract】: THz communication has the potential to realize an order of magnitude increase in data rates due to the availability of wide THz-scale spectral bands. Unfortunately, establishing and managing highly directional beams in THz networks is challenging as links lack the "pseudo-omni" reception capability of lower bands and the product of AP-client beam resolution is high due to narrow beams of only a few degrees. In this paper, we present One-shot Path discovEry with a THz RAinbow (OPERA), a novel system that identifies dominant paths between the AP and all clients in order to efficiently steer directional beams. The key idea is to embed path direction into the inherent characteristics of signals traveling along each path. To do so, we exploit a single leaky wave antenna and create a THz Rainbow. A THz Rainbow transmission consists of distinct signals with unique spectral characteristics across the angular domain. Leveraging the spatial-spectral signatures in the THz Rainbow, all receivers can correlate the measured signal with the known transmission signatures to discover the sender's path directions in one-shot. Our experiments demonstrate that OPERA achieves average direction estimates within 2° of ground truth for LOS and reflected paths.
【Keywords】: Networks; Network protocols; Network protocol design; Network types; Mobile networks; Wireless access networks; Wireless local area networks
【Paper Link】 【Pages】:19:1-19:14
【Authors】: Hua Huang ; Shan Lin
【Abstract】: Electric toothbrushes are widely used for home oral care, but many users do not achieve desired hygiene results due to insufficient brushing coverage or incorrect brushing techniques. Existing electric toothbrushing monitoring systems fail to detect these issues because they cannot achieve fine-grained position tracking. In this paper, we present a novel electric toothbrushing monitoring system called MET that tracks brushing coverage for all the 15 surfaces of teeth and detects different types of incorrect brushing techniques. This design is inspired by our observation that the motor inside an electric toothbrush generates a unique magnetic field, which can serve as a reliable signal for position and orientation tracking. MET is the first system that tracks both the position and orientation of an unmodified electric motor using magnetic inductive sensing. Experiments with fourteen users show that the average toothbrushing surface recognition accuracy of MET is 85.3%. Moreover, MET is robust to user location changes and posture variations and does not require any training from the users. Experimental results also demonstrate our significant advantages over existing commercial systems.
【Keywords】: Computer systems organization; Embedded and cyber-physical systems; Human-centered computing; Ubiquitous and mobile computing; Ubiquitous and mobile computing systems and tools
【Paper Link】 【Pages】:20:1-20:11
【Authors】: Mingliang Li ; Hao Lin ; Cai Liu ; Zhenhua Li ; Feng Qian ; Yunhao Liu ; Nian Sun ; Tianyin Xu
【Abstract】: Almost every Android user has unsatisfying experiences regarding responsiveness, in particular Application Not Responding (ANR) and System Not Responding (SNR) that directly disrupt user experience. Unfortunately, the community have limited understanding of the prevalence, characteristics, and root causes of unresponsiveness. In this paper, we make an in-depth study of ANR and SNR at scale based on fine-grained system-level traces crowdsourced from 30,000 Android systems. We find that ANR and SNR occur prevalently on all the studied 15 hardware models, and better hardware does not seem to relieve the problem. Moreover, as Android evolves from version 7.0 to 9.0, there are fewer ANR events but more SNR events. Most importantly, we uncover multifold root causes of ANR and SNR and pinpoint the largest inefficiency which roots in Android's flawed implementation of Write Amplification Mitigation (WAM). We design a practical approach to eliminating this largest root cause; after large-scale deployment, it reduces almost all (>99%) ANR and SNR caused by WAM while only decreasing 3% of the data write speed. In addition, we document important lessons we have learned from this study, and have also released our measurement code/data to the research community.
【Keywords】: Human-centered computing; Ubiquitous and mobile computing; Ubiquitous and mobile computing systems and tools; Ubiquitous and mobile devices; Mobile phones; Software and its engineering; Software creation and management; Software verification and validation; Software defect analysis; Software testing and debugging; Software organization and properties; Contextual software domains; Operating systems; File systems management; Extra-functional properties; Software performance
【Paper Link】 【Pages】:21:1-21:14
【Authors】: Yaman Sangar ; Bhuvana Krishnaswamy
【Abstract】: Wireless communication over long distances has become the bottleneck for battery-powered, large-scale deployments. Currently used low-power protocols such as Zigbee and Bluetooth Low Energy have limited communication range, whereas long-range communication strategies used in cellular and satellite networks are heavy on energy consumption. Methods that use narrow-band communication such as LoRa, SigFox, and NB-IoT have low spectral efficiency, leading to scalability issues. The goal of this work is to develop a communication framework that can satisfy the following requirements: (1) Increased battery life, (2) Longer communication range, (3) Scalability in a wireless network. In this work, we propose, design, and prototype WiChronos, a communication paradigm that encodes information in the time interval between two narrowband symbols in order to drastically reduce the energy consumption in a wide area network with a large number of senders. We leverage the low data-rate and relaxed latency requirements of such applications to achieve the desired features identified above. Based on our prototype using off-the-shelf components, WiChronos achieves an impressive 60% improvement in battery life compared to state-of-the-art LPWAN technologies at distances of over 800 meters. We also show that more than 1000 WiChronos senders can co-exist with less than 5% probability of collisions under low traffic conditions.
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【Paper Link】 【Pages】:22:1-22:15
【Authors】: Xiaoran Fan ; Longfei Shangguan ; Richard E. Howard ; Yanyong Zhang ; Yao Peng ; Jie Xiong ; Yunfei Ma ; Xiang-Yang Li
【Abstract】: This paper presents the design, implementation and evaluation of In-N-Out, a software-hardware solution for far-field wireless power transfer. In-N-Out can continuously charge a medical implant residing in deep tissues at near-optimal beamforming power, even when the implant moves around inside the human body. To accomplish this, we exploit the unique energy ball pattern of distributed antenna array and devise a backscatter-assisted beamforming algorithm that can concentrate RF energy on a tiny spot surrounding the medical implant. Meanwhile, the power levels on other body parts stay in low level, reducing the risk of overheating. We proto-type In-N-Out on 21 software-defined radios and a printed circuit board (PCB). Extensive experiments demonstrate that In-N-Out achieves 0.37 mW average charging power inside a 10 cm-thick pork belly, which is sufficient to wirelessly power a range of commercial medical devices. Our head-to-head comparison with the state-of-the-art approach shows that In-N-Out achieves 5.4X-18.1X power gain when the implant is stationary, and 5.3X-7.4X power gain when the implant is in motion.
【Keywords】: Hardware; Communication hardware, interfaces and storage; Wireless devices; Emerging technologies; Biology-related information processing; Bio-embedded electronics; Power and energy; Power estimation and optimization; Platform power issues; Networks; Network components; Wireless access points, base stations and infrastructure
【Paper Link】 【Pages】:23:1-23:14
【Authors】: Wenjun Jiang ; Hongfei Xue ; Chenglin Miao ; Shiyang Wang ; Sen Lin ; Chong Tian ; Srinivasan Murali ; Haochen Hu ; Zhi Sun ; Lu Su
【Abstract】: This paper presents WiPose, the first 3D human pose construction framework using commercial WiFi devices. From the pervasive WiFi signals, WiPose can reconstruct 3D skeletons composed of the joints on both limbs and torso of the human body. By overcoming the technical challenges faced by traditional camera-based human perception solutions, such as lighting and occlusion, the proposed WiFi human sensing technique demonstrates the potential to enable a new generation of applications such as health care, assisted living, gaming, and virtual reality. WiPose is based on a novel deep learning model that addresses a series of technical challenges. First, WiPose can encode the prior knowledge of human skeleton into the posture construction process to ensure the estimated joints satisfy the skeletal structure of the human body. Second, to achieve cross environment generalization, WiPose takes as input a 3D velocity profile which can capture the movements of the whole 3D space, and thus separate posture-specific features from the static objects in the ambient environment. Finally, WiPose employs a recurrent neural network (RNN) and a smooth loss to enforce smooth movements of the generated skeletons. Our evaluation results on a real-world WiFi sensing testbed with distributed antennas show that WiPose can localize each joint on the human skeleton with an average error of 2.83cm, achieving a 35% improvement in accuracy over the state-of-the-art posture construction model designed for dedicated radar sensors.
【Keywords】: Human-centered computing; Human computer interaction (HCI); Interaction techniques; Networks; Network components; Wireless access points, base stations and infrastructure
【Paper Link】 【Pages】:24:1-24:13
【Authors】: Xiangyu Xu ; Jiadi Yu ; Yingying Chen ; Qin Hua ; Yanmin Zhu ; Yi-Chao Chen ; Minglu Li
【Abstract】: With increasing private and sensitive data stored in mobile devices, secure and effective mobile-based user authentication schemes are desired. As the most natural way to contact with mobile devices, finger touches have shown potentials for user authentication. Most existing approaches utilize finger touches as behavioral biometrics for identifying individuals, which are vulnerable to spoofer attacks. To resist attacks for on-touch user authentication on mobile devices, this paper exploits physical characters of touching fingers by investigating active vibration signal transmission through fingers, and we find that physical characters of touching fingers present unique patterns on active vibration signals for different individuals. Based on the observation, we propose a behavior-irrelevant on-touch user authentication system, TouchPass, which leverages active vibration signals on smartphones to extract only physical characters of touching fingers for user identification. TouchPass first extracts features that mix physical characters of touching fingers and behavior biometrics of touching behaviors from vibration signals generated and received by smartphones. Then, we design a Siamese network-based architecture with a specific training sample selection strategy to reconstruct the extracted signal features to behavior-irrelevant features and further build a behavior-irrelevant on-touch user authentication scheme leveraging knowledge distillation. Our extensive experiments validate that TouchPass can accurately authenticate users and defend various attacks.
【Keywords】: Security and privacy; Security services; Authentication