Welcome to ACM MobiCom 2015, the 21st Annual International Conference on Mobile Computing and Networking. MobiCom is the premier forum for publishing and presenting cutting-edge research in mobile systems and wireless networks. The technical program this year features 38 outstanding papers that cover a wide variety of topics including energy, sensing, security, wireless access, applications, localization, Internet of things, mobile cloud, measurement and analysis. We created a new Experience track this year to encourage authors to present extensive experiences with implementation, deployment, and operations of mobile ncomputing and wireless networks. One of the accepted papers is an Experience paper on cellular networks. This year's call for papers attracted 207 qualified submissions from across the globe that were carefully reviewed by 46 Technical Program Committee (TPC) members (+2 TPC chairs) along with a selected group of external experts. The TPC was formed with the goal of covering diverse research expertise as well as diverse perspectives and approaches. The TPC included researchers from 12 countries including China, France, Germany, India, Italy, Singapore, South Korea, Spain, Sweden, Switzerland, UK, and USA. 25% of the members were female, the highest ever in the history of MobiCom. We also had broad industry participation with TPC members from Alcatel-Lucent, Google, HP, IBM, Microsoft, NEC, and Telefonica. The paper review process was double-blinded and carried out in three phases. In the first phase, each paper was reviewed by at least three TPC members, and the top 112 papers were selected for the second phase. In addition to reviewer scores, reviewer confidence and normalization with respect to other papers in a reviewer's pile, were also considered in selecting papers. In the second phase, each paper was reviewed by at least two more reviewers followed by an online, often intense, discussion, producing 68 papers for the final phase. The final TPC meeting was held on May 28th and 29th in Salt Lake City, Utah. These 68 papers were organized by their topic areas, and discussed at length at the meeting. Eventually, 38 papers were shortlisted for inclusion in the program and a shepherd from the TPC was assigned to each of these papers. As the last step, each of the shortlisted papers was shepherded through a "blind" process where the authors interacted with all the reviewers and the shepherd to address the review comments without knowing the reviewers' or the shepherds' identities. The end result is an exciting technical program composed of 38 very high quality papers. During the review process, Prof. Robin Kravets, the TPC co-chair of MobiCom 2013, handled the papers that were co-authored by TPC chairs, and those that had conflict-of-interest with both TPC chairs. To ensure fairness and preserve the anonymity of all authors and reviewers, the assignment of reviewers, the reviews and discussions of these papers were done out
{"title":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","authors":"S. Fdida, G. Pau, S. Kasera, H. Zheng","doi":"10.1145/2789168","DOIUrl":"https://doi.org/10.1145/2789168","url":null,"abstract":"Welcome to ACM MobiCom 2015, the 21st Annual International Conference on Mobile Computing and Networking. MobiCom is the premier forum for publishing and presenting cutting-edge research in mobile systems and wireless networks. The technical program this year features 38 outstanding papers that cover a wide variety of topics including energy, sensing, security, wireless access, applications, localization, Internet of things, mobile cloud, measurement and analysis. We created a new Experience track this year to encourage authors to present extensive experiences with implementation, deployment, and operations of mobile ncomputing and wireless networks. One of the accepted papers is an Experience paper on cellular networks. \u0000 \u0000This year's call for papers attracted 207 qualified submissions from across the globe that were carefully reviewed by 46 Technical Program Committee (TPC) members (+2 TPC chairs) along with a selected group of external experts. The TPC was formed with the goal of covering diverse research expertise as well as diverse perspectives and approaches. The TPC included researchers from 12 countries including China, France, Germany, India, Italy, Singapore, South Korea, Spain, Sweden, Switzerland, UK, and USA. 25% of the members were female, the highest ever in the history of MobiCom. We also had broad industry participation with TPC members from Alcatel-Lucent, Google, HP, IBM, Microsoft, NEC, and Telefonica. \u0000 \u0000The paper review process was double-blinded and carried out in three phases. In the first phase, each paper was reviewed by at least three TPC members, and the top 112 papers were selected for the second phase. In addition to reviewer scores, reviewer confidence and normalization with respect to other papers in a reviewer's pile, were also considered in selecting papers. In the second phase, each paper was reviewed by at least two more reviewers followed by an online, often intense, discussion, producing 68 papers for the final phase. The final TPC meeting was held on May 28th and 29th in Salt Lake City, Utah. These 68 papers were organized by their topic areas, and discussed at length at the meeting. Eventually, 38 papers were shortlisted for inclusion in the program and a shepherd from the TPC was assigned to each of these papers. As the last step, each of the shortlisted papers was shepherded through a \"blind\" process where the authors interacted with all the reviewers and the shepherd to address the review comments without knowing the reviewers' or the shepherds' identities. The end result is an exciting technical program composed of 38 very high quality papers. \u0000 \u0000During the review process, Prof. Robin Kravets, the TPC co-chair of MobiCom 2013, handled the papers that were co-authored by TPC chairs, and those that had conflict-of-interest with both TPC chairs. To ensure fairness and preserve the anonymity of all authors and reviewers, the assignment of reviewers, the reviews and discussions of these papers were done out ","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128985910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shailendra Singh, H. Madhyastha, S. Krishnamurthy, R. Govindan
To reduce page load times and bandwidth usage for mobile web browsing, middleboxes that compress page content are commonly used today. Unfortunately, this can hurt performance in many cases; via an extensive measurement study, we show that using middleboxes to facilitate compression results in up to 28% degradation in page load times when the client enjoys excellent wireless link conditions. We find that benefits from compression are primarily realized under bad network conditions. Guided by our study, we design and implement FlexiWeb, a framework that determines both when to use a middlebox and how to use it, based on the client's network conditions. First, FlexiWeb selectively fetches objects on a web page either directly from the source or via a middlebox, rather than fetching all objects via the middlebox. Second, instead of simply performing lossless compression of all content, FlexiWeb performs network-aware compression of images by selecting from among a range of content transformations. We implement and evaluate a prototype of FlexiWeb using Google's open source Chromium mobile browser and our implementation of a modified version of Google's open source compression proxy. Our extensive experiments show that, across a range of scenarios, FlexiWeb reduces page load times for mobile clients by 35-42% compared to the status quo.
{"title":"FlexiWeb: Network-Aware Compaction for Accelerating Mobile Web Transfers","authors":"Shailendra Singh, H. Madhyastha, S. Krishnamurthy, R. Govindan","doi":"10.1145/2789168.2790128","DOIUrl":"https://doi.org/10.1145/2789168.2790128","url":null,"abstract":"To reduce page load times and bandwidth usage for mobile web browsing, middleboxes that compress page content are commonly used today. Unfortunately, this can hurt performance in many cases; via an extensive measurement study, we show that using middleboxes to facilitate compression results in up to 28% degradation in page load times when the client enjoys excellent wireless link conditions. We find that benefits from compression are primarily realized under bad network conditions. Guided by our study, we design and implement FlexiWeb, a framework that determines both when to use a middlebox and how to use it, based on the client's network conditions. First, FlexiWeb selectively fetches objects on a web page either directly from the source or via a middlebox, rather than fetching all objects via the middlebox. Second, instead of simply performing lossless compression of all content, FlexiWeb performs network-aware compression of images by selecting from among a range of content transformations. We implement and evaluate a prototype of FlexiWeb using Google's open source Chromium mobile browser and our implementation of a modified version of Google's open source compression proxy. Our extensive experiments show that, across a range of scenarios, FlexiWeb reduces page load times for mobile clients by 35-42% compared to the status quo.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130989581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tianxing Li, Chuankai An, Tian Zhao, A. Campbell, Xia Zhou
We present LiSense, the first-of-its-kind system that enables both data communication and fine-grained, real-time human skeleton reconstruction using Visible Light Communication (VLC). LiSense uses shadows created by the human body from blocked light and reconstructs 3D human skeleton postures in real time. We overcome two key challenges to realize shadow-based human sensing. First, multiple lights on the ceiling lead to diminished and complex shadow patterns on the floor. We design light beacons enabled by VLC to separate light rays from different light sources and recover the shadow pattern cast by each individual light. Second, we design an efficient inference algorithm to reconstruct user postures using 2D shadow information with a limited resolution collected by photodiodes embedded in the floor. We build a 3 m x 3 m LiSense testbed using off-the-shelf LEDs and photodiodes. Experiments show that LiSense reconstructs the 3D user skeleton at 60 Hz in real time with 10 degrees mean angular error for five body joints.
{"title":"Human Sensing Using Visible Light Communication","authors":"Tianxing Li, Chuankai An, Tian Zhao, A. Campbell, Xia Zhou","doi":"10.1145/2789168.2790110","DOIUrl":"https://doi.org/10.1145/2789168.2790110","url":null,"abstract":"We present LiSense, the first-of-its-kind system that enables both data communication and fine-grained, real-time human skeleton reconstruction using Visible Light Communication (VLC). LiSense uses shadows created by the human body from blocked light and reconstructs 3D human skeleton postures in real time. We overcome two key challenges to realize shadow-based human sensing. First, multiple lights on the ceiling lead to diminished and complex shadow patterns on the floor. We design light beacons enabled by VLC to separate light rays from different light sources and recover the shadow pattern cast by each individual light. Second, we design an efficient inference algorithm to reconstruct user postures using 2D shadow information with a limited resolution collected by photodiodes embedded in the floor. We build a 3 m x 3 m LiSense testbed using off-the-shelf LEDs and photodiodes. Experiments show that LiSense reconstructs the 3D user skeleton at 60 Hz in real time with 10 degrees mean angular error for five body joints.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128588448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Yang, Qiongzheng Lin, Xiangyang Li, Tianci Liu, Yunhao Liu
Through-wall tracking has gained a lot of attentions in civilian applications recently. Many applications would benefit from such device-free tracking, e.g. elderly people surveillance, intruder detection, gaming, etc. In this work, we present a system, named Tadar, for tracking moving objects without instrumenting them us- ing COTS RFID readers and tags. It works even through walls and behind closed doors. It aims to enable a see-through-wall technology that is low-cost, compact, and accessible to civilian purpose. In traditional RFID systems, tags modulate their IDs on the backscatter signals, which is vulnerable to the interferences from the ambient reflections. Unlike past work, which considers such vulnerability as detrimental, our design exploits it to detect surrounding objects even through walls. Specifically, we attach a group of RFID tags on the outer wall and logically convert them into an antenna array, receiving the signals reflected off moving objects. This paper introduces two main innovations. First, it shows how to eliminate the flash (e.g. the stronger reflections off walls) and extract the reflections from the backscatter signals. Second, it shows how to track the moving object based on HMM (Hidden Markov Model) and its reflections. To the best of our knowledge, we are the first to implement a through-wall tracking using the COTS RFID systems. Empirical measurements with a prototype show that Tadar can detect objects behind 5" hollow wall and 8" concrete wall, and achieve median tracking errors of 7.8cm and 20cm in the X and Y dimensions.
{"title":"See Through Walls with COTS RFID System!","authors":"Lei Yang, Qiongzheng Lin, Xiangyang Li, Tianci Liu, Yunhao Liu","doi":"10.1145/2789168.2790100","DOIUrl":"https://doi.org/10.1145/2789168.2790100","url":null,"abstract":"Through-wall tracking has gained a lot of attentions in civilian applications recently. Many applications would benefit from such device-free tracking, e.g. elderly people surveillance, intruder detection, gaming, etc. In this work, we present a system, named Tadar, for tracking moving objects without instrumenting them us- ing COTS RFID readers and tags. It works even through walls and behind closed doors. It aims to enable a see-through-wall technology that is low-cost, compact, and accessible to civilian purpose. In traditional RFID systems, tags modulate their IDs on the backscatter signals, which is vulnerable to the interferences from the ambient reflections. Unlike past work, which considers such vulnerability as detrimental, our design exploits it to detect surrounding objects even through walls. Specifically, we attach a group of RFID tags on the outer wall and logically convert them into an antenna array, receiving the signals reflected off moving objects. This paper introduces two main innovations. First, it shows how to eliminate the flash (e.g. the stronger reflections off walls) and extract the reflections from the backscatter signals. Second, it shows how to track the moving object based on HMM (Hidden Markov Model) and its reflections. To the best of our knowledge, we are the first to implement a through-wall tracking using the COTS RFID systems. Empirical measurements with a prototype show that Tadar can detect objects behind 5\" hollow wall and 8\" concrete wall, and achieve median tracking errors of 7.8cm and 20cm in the X and Y dimensions.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125126867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the design and implementation of AirExpress, a system that enables in-band wireless cut-through transmission. Unlike wired cut-through, wireless cut-through can reduce latency and improve throughput performance of the network at the same time. In AirExpress, all the forwarders along the cut-through path forward the signal they received immediately without decoding. The hierarchical structure of AirExpress enables its interference cancellation ability to handle all kinds of interference among the radios. Novel MAC and routing algorithms based on cut-through transmission are also proposed to support the realization of AirExpress in multi-hop mesh networks. AirExpress is implemented on an NI-based SDR platform. Through experiments in the 2.4GHz ISM band, we show throughput gain of up to 3.4 times with a 4-hop AirExpress system. Trace driven evaluation of AirExpress on the NS3 platform shows an average throughput gain of 2.85 for AirExpress over optimal TDMA.
{"title":"AirExpress: Enabling Seamless In-band Wireless Multi-hop Transmission","authors":"Bo Chen, Yue Qiao, Ouyang Zhang, K. Srinivasan","doi":"10.1145/2789168.2790114","DOIUrl":"https://doi.org/10.1145/2789168.2790114","url":null,"abstract":"This paper describes the design and implementation of AirExpress, a system that enables in-band wireless cut-through transmission. Unlike wired cut-through, wireless cut-through can reduce latency and improve throughput performance of the network at the same time. In AirExpress, all the forwarders along the cut-through path forward the signal they received immediately without decoding. The hierarchical structure of AirExpress enables its interference cancellation ability to handle all kinds of interference among the radios. Novel MAC and routing algorithms based on cut-through transmission are also proposed to support the realization of AirExpress in multi-hop mesh networks. AirExpress is implemented on an NI-based SDR platform. Through experiments in the 2.4GHz ISM band, we show throughput gain of up to 3.4 times with a 4-hop AirExpress system. Trace driven evaluation of AirExpress on the NS3 platform shows an average throughput gain of 2.85 for AirExpress over optimal TDMA.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123054847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chi Zhang, Josh Tabor, Jialiang Zhang, Xinyu Zhang
Mobile devices are shrinking their form factors for portability, but user-mobile interaction is becoming increasingly challenging. In this paper, we propose a novel system called Okuli to meet this challenge. Okuli is a compact, low-cost system that can augment a mobile device and extend its interaction workspace to any nearby surface area. Okuli piggybacks on visible light communication modules, and uses a low-power LED and two light sensors to locate user's finger within the workspace. It is built on a light propagation/reflection model that achieves around one-centimeter location precision, with zero run-time training overhead. We have prototyped Okuli as an Android peripheral, with a 3D-printed shroud to host the LED and light sensors. Our experiments demonstrate Okuli's accuracy, stability, energy efficiency, as well as its potential in serving virtual keyboard and trackpad applications.
{"title":"Extending Mobile Interaction Through Near-Field Visible Light Sensing","authors":"Chi Zhang, Josh Tabor, Jialiang Zhang, Xinyu Zhang","doi":"10.1145/2789168.2790115","DOIUrl":"https://doi.org/10.1145/2789168.2790115","url":null,"abstract":"Mobile devices are shrinking their form factors for portability, but user-mobile interaction is becoming increasingly challenging. In this paper, we propose a novel system called Okuli to meet this challenge. Okuli is a compact, low-cost system that can augment a mobile device and extend its interaction workspace to any nearby surface area. Okuli piggybacks on visible light communication modules, and uses a low-power LED and two light sensors to locate user's finger within the workspace. It is built on a light propagation/reflection model that achieves around one-centimeter location precision, with zero run-time training overhead. We have prototyped Okuli as an Android peripheral, with a 3D-printed shroud to host the LED and light sensors. Our experiments demonstrate Okuli's accuracy, stability, energy efficiency, as well as its potential in serving virtual keyboard and trackpad applications.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114492738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gaetan Harter, R. Pissard-Gibollet, Frederic Saint-Marcel, G. Schreiner, J. Vandaele
FIT IoT-LAB's goal is to provide a very large scale open experimental testbed for the Internet of Things, by deploying more than 2700 experimentation nodes over 6 sites in France. Our demonstration purpose is to illustrate what the IoT-LAB platform offers through small applications involving radio communications and mobile nodes. Thanks to these examples, we will show how to run an experiment in the testbed and some of the tools it provides to help in developing, tuning and monitoring such large-scale applications.
FIT IoT-LAB的目标是通过在法国的6个站点部署2700多个实验节点，为物联网提供一个非常大规模的开放实验测试平台。我们的演示目的是通过涉及无线电通信和移动节点的小型应用来说明IoT-LAB平台提供的功能。通过这些示例，我们将展示如何在测试平台中运行实验，以及它提供的一些工具，以帮助开发、调优和监视此类大规模应用程序。
{"title":"Demo: FIT IoT-LABA: Large Scale Open Experimental IoT Testbed","authors":"Gaetan Harter, R. Pissard-Gibollet, Frederic Saint-Marcel, G. Schreiner, J. Vandaele","doi":"10.1145/2789168.2789172","DOIUrl":"https://doi.org/10.1145/2789168.2789172","url":null,"abstract":"FIT IoT-LAB's goal is to provide a very large scale open experimental testbed for the Internet of Things, by deploying more than 2700 experimentation nodes over 6 sites in France. Our demonstration purpose is to illustrate what the IoT-LAB platform offers through small applications involving radio communications and mobile nodes. Thanks to these examples, we will show how to run an experiment in the testbed and some of the tools it provides to help in developing, tuning and monitoring such large-scale applications.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"190 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116517910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Time synchronization provides the basis for several applications in wireless sensor networks but the limited memory and computational power, and the use of low precision oscillators make the task of time synchronization non-trivial. In this demonstration, we present a novel time synchronization scheme that is based on time series analysis. To provide a general model for the practical behavior of low precision oscillators, autoregressive integrated moving average models are explored. Based on the analysis of experimental data, an autoregressive integrated model (ARI (1,1)) is derived. Unlike the resource hungry Kalman filter based formulations, the proposed scheme is resource efficient as it results in simple linear regression processing. Experiments are performed on real sensor devices including Zolertia and TelosB, where an accuracy below 1 clock tick 1 is achieved.
{"title":"Demo: Exploring Autoregressive Integrated Models for Time Synchronization in Wireless Sensor Networks","authors":"Wasif Masood, J. F. Schmidt","doi":"10.1145/2789168.2789182","DOIUrl":"https://doi.org/10.1145/2789168.2789182","url":null,"abstract":"Time synchronization provides the basis for several applications in wireless sensor networks but the limited memory and computational power, and the use of low precision oscillators make the task of time synchronization non-trivial. In this demonstration, we present a novel time synchronization scheme that is based on time series analysis. To provide a general model for the practical behavior of low precision oscillators, autoregressive integrated moving average models are explored. Based on the analysis of experimental data, an autoregressive integrated model (ARI (1,1)) is derived. Unlike the resource hungry Kalman filter based formulations, the proposed scheme is resource efficient as it results in simple linear regression processing. Experiments are performed on real sensor devices including Zolertia and TelosB, where an accuracy below 1 clock tick 1 is achieved.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125270933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiufeng Xie, Eugene Chai, Xinyu Zhang, K. Sundaresan, M. Khojastepour, S. Rangarajan
Large-scale multiuser MIMO (MU-MIMO) systems have the potential for multi-fold scaling of network capacity. The research community has recognized this theoretical potential and developed architectures [1,2] with large numbers of RF chains. Unfortunately, building the hardware with a large number of RF chains is challenging in practice. CSI data transport and computational overhead of MU-MIMO beamforming can also become prohibitive under large network scale. Furthermore, it is difficult to physically append extra RF chains on existing communication equipments to support such large-scale MU-MIMO architectures. In this paper, we present Hekaton, a novel large-scale MU-MIMO framework that combines legacy MU-MIMO beamforming with phased-array antennas. The core of Hekaton is a two-level beamforming architecture. First, the phased-array antennas steer spatial beams toward each downlink user to reduce channel correlation and suppress the cross-talk interference in the RF domain (for beamforming gain), then we adopt legacy digital beamforming to eliminate the interference between downlink data streams (for spatial multiplexing gain). In this way, Hekaton realizes a good fraction of potential large-scale MU-MIMO gains even under the limited RF chain number on existing communication equipments. We evaluate the performance of Hekaton through over-the-air testbed built over the WARPv3 platform and trace-driven emulation. In the evaluations, Hekaton can improve single-cell throughput by up to 2.5X over conventional MU-MIMO with a single antenna per RF chain, while using the same transmit power.
{"title":"Hekaton: Efficient and Practical Large-Scale MIMO","authors":"Xiufeng Xie, Eugene Chai, Xinyu Zhang, K. Sundaresan, M. Khojastepour, S. Rangarajan","doi":"10.1145/2789168.2790116","DOIUrl":"https://doi.org/10.1145/2789168.2790116","url":null,"abstract":"Large-scale multiuser MIMO (MU-MIMO) systems have the potential for multi-fold scaling of network capacity. The research community has recognized this theoretical potential and developed architectures [1,2] with large numbers of RF chains. Unfortunately, building the hardware with a large number of RF chains is challenging in practice. CSI data transport and computational overhead of MU-MIMO beamforming can also become prohibitive under large network scale. Furthermore, it is difficult to physically append extra RF chains on existing communication equipments to support such large-scale MU-MIMO architectures. In this paper, we present Hekaton, a novel large-scale MU-MIMO framework that combines legacy MU-MIMO beamforming with phased-array antennas. The core of Hekaton is a two-level beamforming architecture. First, the phased-array antennas steer spatial beams toward each downlink user to reduce channel correlation and suppress the cross-talk interference in the RF domain (for beamforming gain), then we adopt legacy digital beamforming to eliminate the interference between downlink data streams (for spatial multiplexing gain). In this way, Hekaton realizes a good fraction of potential large-scale MU-MIMO gains even under the limited RF chain number on existing communication equipments. We evaluate the performance of Hekaton through over-the-air testbed built over the WARPv3 platform and trace-driven emulation. In the evaluations, Hekaton can improve single-cell throughput by up to 2.5X over conventional MU-MIMO with a single antenna per RF chain, while using the same transmit power.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125848591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xueshu Zheng, Naigao Jin, Lei Wang, Mathew L. Wymore, D. Qiao
This paper presents DiVA, a new acoustic source localization scheme that uses an ad-hoc network of microphone sensor nodes to produce an accurate estimate of the source's location. DiVA uses pairwise comparisons of sound detection timestamps between local Voronoi neighbors to identify the node closest to the acoustic source and then estimates the source's location. The scheme improves on the state of the art by effectively dealing with anchor nodes' position error, time stamp measurement error and time synchronization error in real world conditions. Through simulation and experimental evaluations, DiVA is shown to be more robust than existing solutions under different error conditions.
{"title":"Poster: Distributed Voronoi-based Acoustic Source Localization with Wireless Sensor Networks","authors":"Xueshu Zheng, Naigao Jin, Lei Wang, Mathew L. Wymore, D. Qiao","doi":"10.1145/2789168.2795178","DOIUrl":"https://doi.org/10.1145/2789168.2795178","url":null,"abstract":"This paper presents DiVA, a new acoustic source localization scheme that uses an ad-hoc network of microphone sensor nodes to produce an accurate estimate of the source's location. DiVA uses pairwise comparisons of sound detection timestamps between local Voronoi neighbors to identify the node closest to the acoustic source and then estimates the source's location. The scheme improves on the state of the art by effectively dealing with anchor nodes' position error, time stamp measurement error and time synchronization error in real world conditions. Through simulation and experimental evaluations, DiVA is shown to be more robust than existing solutions under different error conditions.","PeriodicalId":424497,"journal":{"name":"Proceedings of the 21st Annual International Conference on Mobile Computing and Networking","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129564685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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