Abusayeed Saifullah, Mahbubur Rahman, Dali Ismail, Chenyang Lu, Jie Liu, Ranveer Chandra
Low-Power Wide-Area Network (LPWAN) heralds a promising class of technology to overcome the range limits and scalability challenges in traditional wireless sensor networks. Recently proposed Sensor Network over White Spaces (SNOW) technology is particularly attractive due to the availability and advantages of TV spectrum in long-range communication. This paper proposes a new design of SNOW that is asynchronous, reliable, and robust. It represents the first highly scalable LPWAN over TV white spaces to support reliable, asynchronous, bi-directional, and concurrent communication between numerous sensors and a base station. This is achieved through a set of novel techniques. This new design of SNOW has an OFDM based physical layer that adopts robust modulation scheme and allows the base station using a single antenna-radio (1) to send different data to different nodes concurrently and (2) to receive concurrent transmissions made by the sensor nodes asynchronously. It has a lightweight MAC protocol that (1) efficiently implements per-transmission acknowledgments of the asynchronous transmissions by exploiting the adopted OFDM design; (2) combines CSMA/CA and location-aware spectrum allocation for mitigating hidden terminal effects, thus enhancing the flexibility of the nodes in transmitting asynchronously. Hardware experiments through deployments in three radio environments - in a large metropolitan city, in a rural area, and in an indoor environment - as well as large-scale simulations demonstrated that the new SNOW design drastically outperforms other LPWAN technologies in terms of scalability, energy, and latency.
{"title":"Enabling Reliable, Asynchronous, and Bidirectional Communication in Sensor Networks over White Spaces","authors":"Abusayeed Saifullah, Mahbubur Rahman, Dali Ismail, Chenyang Lu, Jie Liu, Ranveer Chandra","doi":"10.1145/3131672.3131676","DOIUrl":"https://doi.org/10.1145/3131672.3131676","url":null,"abstract":"Low-Power Wide-Area Network (LPWAN) heralds a promising class of technology to overcome the range limits and scalability challenges in traditional wireless sensor networks. Recently proposed Sensor Network over White Spaces (SNOW) technology is particularly attractive due to the availability and advantages of TV spectrum in long-range communication. This paper proposes a new design of SNOW that is asynchronous, reliable, and robust. It represents the first highly scalable LPWAN over TV white spaces to support reliable, asynchronous, bi-directional, and concurrent communication between numerous sensors and a base station. This is achieved through a set of novel techniques. This new design of SNOW has an OFDM based physical layer that adopts robust modulation scheme and allows the base station using a single antenna-radio (1) to send different data to different nodes concurrently and (2) to receive concurrent transmissions made by the sensor nodes asynchronously. It has a lightweight MAC protocol that (1) efficiently implements per-transmission acknowledgments of the asynchronous transmissions by exploiting the adopted OFDM design; (2) combines CSMA/CA and location-aware spectrum allocation for mitigating hidden terminal effects, thus enhancing the flexibility of the nodes in transmitting asynchronously. Hardware experiments through deployments in three radio environments - in a large metropolitan city, in a rural area, and in an indoor environment - as well as large-scale simulations demonstrated that the new SNOW design drastically outperforms other LPWAN technologies in terms of scalability, energy, and latency.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129332992","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}
Tracking user's eye fixation direction is crucial to virtual reality (VR): it eases user's interaction with the virtual scene and enables intelligent rendering to improve user's visual experiences and save system energy. Existing techniques commonly rely on cameras and active infrared emitters, making them too expensive and power-hungry for VR headsets (especially mobile VR headsets). We present LiGaze, a low-cost, low-power approach to gaze tracking tailored to VR. It relies on a few low-cost photodiodes, eliminating the need for cameras and active infrared emitters. Reusing light emitted from the VR screen, LiGaze leverages photodiodes around a VR lens to measure reflected screen light in different directions. It then infers gaze direction by exploiting pupil's light absorption property. The core of LiGaze is to deal with screen light dynamics and extract changes in reflected light related to pupil movement. LiGaze infers a 3D gaze vector on the fly using a lightweight regression algorithm. We design and fabricate a LiGaze prototype using off-the-shelf photodiodes. Our comparison to a commercial VR eye tracker (FOVE) shows that LiGaze achieves 6.3° and 10.1° mean within-user and cross-user accuracy. Its sensing and computation consume 791μW in total and thus can be completely powered by a credit-card sized solar cell harvesting energy from indoor lighting. LiGaze's simplicity and ultra-low power make it applicable in a wide range of VR headsets to better unleash VR's potential.
{"title":"Ultra-Low Power Gaze Tracking for Virtual Reality","authors":"Tianxing Li, Qiang Liu, Xia Zhou","doi":"10.1145/3131672.3131682","DOIUrl":"https://doi.org/10.1145/3131672.3131682","url":null,"abstract":"Tracking user's eye fixation direction is crucial to virtual reality (VR): it eases user's interaction with the virtual scene and enables intelligent rendering to improve user's visual experiences and save system energy. Existing techniques commonly rely on cameras and active infrared emitters, making them too expensive and power-hungry for VR headsets (especially mobile VR headsets). We present LiGaze, a low-cost, low-power approach to gaze tracking tailored to VR. It relies on a few low-cost photodiodes, eliminating the need for cameras and active infrared emitters. Reusing light emitted from the VR screen, LiGaze leverages photodiodes around a VR lens to measure reflected screen light in different directions. It then infers gaze direction by exploiting pupil's light absorption property. The core of LiGaze is to deal with screen light dynamics and extract changes in reflected light related to pupil movement. LiGaze infers a 3D gaze vector on the fly using a lightweight regression algorithm. We design and fabricate a LiGaze prototype using off-the-shelf photodiodes. Our comparison to a commercial VR eye tracker (FOVE) shows that LiGaze achieves 6.3° and 10.1° mean within-user and cross-user accuracy. Its sensing and computation consume 791μW in total and thus can be completely powered by a credit-card sized solar cell harvesting energy from indoor lighting. LiGaze's simplicity and ultra-low power make it applicable in a wide range of VR headsets to better unleash VR's potential.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115930715","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}
Sven Akkermans, Nicolas Small, W. Joosen, D. Hughes
The state-of-practice for Internet of Things (IoT) applications is deployment on specialised networks of embedded devices connected to a cloud backend. This paradigm is limited by the high latency and bandwidth incurred by communications with remote data servers and the inability to share specialised IoT infrastructure across applications. Efficiency can be improved by re-imagining all resources of the IoT infrastructure as micro-service hosting platforms. Applications decomposed as a set of services can then share IoT resources and run communicating modules closer together, tightening control loops and reducing latency and communications. This demo showcases Niflheim, a generic end-to-end middleware that provides modular microservice-based orchestration of applications on all resources across the tiers of the IoT, from IoT end-devices through gateways to the cloud. We demonstrate that this enables increased flexibility in application deployment and operations, while remaining efficient in terms of hardware and software requirements.
{"title":"Niflheim: End-to-End Middleware for Applications Across all Tiers of the IoT","authors":"Sven Akkermans, Nicolas Small, W. Joosen, D. Hughes","doi":"10.1145/3131672.3136975","DOIUrl":"https://doi.org/10.1145/3131672.3136975","url":null,"abstract":"The state-of-practice for Internet of Things (IoT) applications is deployment on specialised networks of embedded devices connected to a cloud backend. This paradigm is limited by the high latency and bandwidth incurred by communications with remote data servers and the inability to share specialised IoT infrastructure across applications. Efficiency can be improved by re-imagining all resources of the IoT infrastructure as micro-service hosting platforms. Applications decomposed as a set of services can then share IoT resources and run communicating modules closer together, tightening control loops and reducing latency and communications. This demo showcases Niflheim, a generic end-to-end middleware that provides modular microservice-based orchestration of applications on all resources across the tiers of the IoT, from IoT end-devices through gateways to the cloud. We demonstrate that this enables increased flexibility in application deployment and operations, while remaining efficient in terms of hardware and software requirements.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"253 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116727263","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}
Uvis Senkans, Domenico Balsamo, Theodoros D. Verykios, G. Merrett
Energy harvesting is an efficient solution to power embedded systems instead of using batteries. However, it has been traditionally coupled with large energy buffers to tackle the temporal variation of the source. These buffers require time to charge and introduce a cost, size and weight overhead. Energy-driven and transiently-powered systems can operate from an energy harvesting source, while containing little or no additional energy storage. However, few real-life applications have been considered for such systems to demonstrate that they can actually be realised. This poster presents a transiently-powered wireless bicycle trip counter which measures distance, speed and active cycling time, and transmits data wirelessly. The system sustains operation by harvesting energy from the rotation of the wheel, operating from 6kph.
{"title":"Applications of Energy-Driven and Transient Computing: A Wireless Bicycle Trip Counter","authors":"Uvis Senkans, Domenico Balsamo, Theodoros D. Verykios, G. Merrett","doi":"10.1145/3131672.3137000","DOIUrl":"https://doi.org/10.1145/3131672.3137000","url":null,"abstract":"Energy harvesting is an efficient solution to power embedded systems instead of using batteries. However, it has been traditionally coupled with large energy buffers to tackle the temporal variation of the source. These buffers require time to charge and introduce a cost, size and weight overhead. Energy-driven and transiently-powered systems can operate from an energy harvesting source, while containing little or no additional energy storage. However, few real-life applications have been considered for such systems to demonstrate that they can actually be realised. This poster presents a transiently-powered wireless bicycle trip counter which measures distance, speed and active cycling time, and transmits data wirelessly. The system sustains operation by harvesting energy from the rotation of the wheel, operating from 6kph.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117287426","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}
Smartphone magnetometer traces can be used to check if the owners moved in proximity. Using time-lagged cross-correlation of the traces, a fine-resolution judgement can be made within a few meters in any formation. The technique works indoors and outdoors, with no communication infrastructure, with less power and higher resolution than GPS, and with less privacy violation than beaconing. Research and practice on human interactions, such as epidemiology and sociology that need fine contact tracing between complete strangers, can harness the technique.
{"title":"Judging Dynamic Co-Existence with Smartphone Magnetometer Traces","authors":"Yong-Weon Jeon, S. Kuk, Hyogon Kim, Yongtae Park","doi":"10.1145/3131672.3136963","DOIUrl":"https://doi.org/10.1145/3131672.3136963","url":null,"abstract":"Smartphone magnetometer traces can be used to check if the owners moved in proximity. Using time-lagged cross-correlation of the traces, a fine-resolution judgement can be made within a few meters in any formation. The technique works indoors and outdoors, with no communication infrastructure, with less power and higher resolution than GPS, and with less privacy violation than beaconing. Research and practice on human interactions, such as epidemiology and sociology that need fine contact tracing between complete strangers, can harness the technique.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117289043","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}
Bernhard Großwindhager, M. Rath, Josef Kulmer, Stefan Hinteregger, M. Bakr, C. Boano, K. Witrisal, K. Römer
In this demo, we present a low-cost indoor localization system based on the off-the-shelf ultra-wideband transceiver Decawave DW1000. To obtain an accurate position information, the system makes use of a single anchor and of multipath reflections from walls, hence removing the need of installing a network of anchors or any other additional infrastructure. The procedure of determining the position of a tag can be divided in four consecutive stages. First, the location of virtual anchors is computed by mirroring the anchor position at reflective surfaces. Using two-way ranging, the distance and channel impulse response (CIR) between anchor and tag is obtained. This actual CIR is compared with expected CIRs from possible tag locations using a maximum likelihood approach to estimate the tag's position. Finally, a switchable directional antenna can be exploited to improve the robustness of the system by suppressing undesired, interfering multipath components. By following this procedure, the proposed system can achieve a decimeter accuracy and react to position updates in real-time.
{"title":"UWB-based Single-anchor Low-cost Indoor Localization System","authors":"Bernhard Großwindhager, M. Rath, Josef Kulmer, Stefan Hinteregger, M. Bakr, C. Boano, K. Witrisal, K. Römer","doi":"10.1145/3131672.3136961","DOIUrl":"https://doi.org/10.1145/3131672.3136961","url":null,"abstract":"In this demo, we present a low-cost indoor localization system based on the off-the-shelf ultra-wideband transceiver Decawave DW1000. To obtain an accurate position information, the system makes use of a single anchor and of multipath reflections from walls, hence removing the need of installing a network of anchors or any other additional infrastructure. The procedure of determining the position of a tag can be divided in four consecutive stages. First, the location of virtual anchors is computed by mirroring the anchor position at reflective surfaces. Using two-way ranging, the distance and channel impulse response (CIR) between anchor and tag is obtained. This actual CIR is compared with expected CIRs from possible tag locations using a maximum likelihood approach to estimate the tag's position. Finally, a switchable directional antenna can be exploited to improve the robustness of the system by suppressing undesired, interfering multipath components. By following this procedure, the proposed system can achieve a decimeter accuracy and react to position updates in real-time.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114155988","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}
Batteryless, energy-harvesting sensing systems are critical to the Internet-of-Things (IoT) vision and sustainable, long-lived, untethered systems. Unfortunately, developing new batteryless applications is challenging. Energy resources are scarce and highly variable, power failures are frequent, and successful applications typically require custom hardware and special expertise. In this paper, we present Flicker, a platform for quickly prototyping batteryless embedded sensors. Flicker is an extensible, modular, "plug and play" architecture that supports RFID, solar, and kinetic energy harvesting; passive and active wireless communication; and a wide range of sensors through common peripheral and harvester interconnects. Flicker supports recent advances in failure-tolerant timekeeping, testing, and debugging, while providing dynamic federated energy storage where peripheral priorities and user tasks can be adjusted without hardware changes. Flicker's software tools automatically detect new hardware configurations, and simplify software changes. We have evaluated the overhead and performance of our Flicker prototype and conducted a case study. We also evaluated the usability of Flicker in a user study with 19 participants, and found it had above average or excellent usability according to the well known System Usability Survey.
{"title":"Flicker: Rapid Prototyping for the Batteryless Internet-of-Things","authors":"Josiah D. Hester, Jacob M. Sorber","doi":"10.1145/3131672.3131674","DOIUrl":"https://doi.org/10.1145/3131672.3131674","url":null,"abstract":"Batteryless, energy-harvesting sensing systems are critical to the Internet-of-Things (IoT) vision and sustainable, long-lived, untethered systems. Unfortunately, developing new batteryless applications is challenging. Energy resources are scarce and highly variable, power failures are frequent, and successful applications typically require custom hardware and special expertise. In this paper, we present Flicker, a platform for quickly prototyping batteryless embedded sensors. Flicker is an extensible, modular, \"plug and play\" architecture that supports RFID, solar, and kinetic energy harvesting; passive and active wireless communication; and a wide range of sensors through common peripheral and harvester interconnects. Flicker supports recent advances in failure-tolerant timekeeping, testing, and debugging, while providing dynamic federated energy storage where peripheral priorities and user tasks can be adjusted without hardware changes. Flicker's software tools automatically detect new hardware configurations, and simplify software changes. We have evaluated the overhead and performance of our Flicker prototype and conducted a case study. We also evaluated the usability of Flicker in a user study with 19 participants, and found it had above average or excellent usability according to the well known System Usability Survey.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116377308","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}
Tiny intermittently powered computers can monitor objects in hard to reach places maintenance free for decades by leaving batteries behind and surviving off energy harvested from the environment--- avoiding the cost of replacing and disposing of billions or trillions of dead batteries. However, creating programs for these sensors is difficult. Energy harvesting is inconsistent, energy storage is scarce, and batteryless sensors can lose power at any point in time--- causing volatile memory, execution progress, and time to reset. In response to these disruptions, developers must write unwieldy programs attempting to protect against failures, instead of focusing on sensing goals, defining tasks, and generating useful data in a timely manner. To address these shortcomings, we have designed Mayfly, a language and runtime for timely execution of sensing tasks on tiny, intermittently-powered, energy harvesting sensing devices. Mayfly is a coordination language and runtime built on top of Embedded-C that combines intermittent execution fragments to form coherent sensing schedules---maintaining forward progress, data consistency, data freshness, and data utility across multiple power failures. Mayfly makes the passing of time explicit, binding data to the time it was gathered, and keeping track of data and time through power failures. We evaluated Mayfly against state-of-the art systems, conducted a user study, and implemented multiple real world applications across application domains in inventory tracking, and wearables.
{"title":"Timely Execution on Intermittently Powered Batteryless Sensors","authors":"Josiah D. Hester, Kevin Storer, Jacob M. Sorber","doi":"10.1145/3131672.3131673","DOIUrl":"https://doi.org/10.1145/3131672.3131673","url":null,"abstract":"Tiny intermittently powered computers can monitor objects in hard to reach places maintenance free for decades by leaving batteries behind and surviving off energy harvested from the environment--- avoiding the cost of replacing and disposing of billions or trillions of dead batteries. However, creating programs for these sensors is difficult. Energy harvesting is inconsistent, energy storage is scarce, and batteryless sensors can lose power at any point in time--- causing volatile memory, execution progress, and time to reset. In response to these disruptions, developers must write unwieldy programs attempting to protect against failures, instead of focusing on sensing goals, defining tasks, and generating useful data in a timely manner. To address these shortcomings, we have designed Mayfly, a language and runtime for timely execution of sensing tasks on tiny, intermittently-powered, energy harvesting sensing devices. Mayfly is a coordination language and runtime built on top of Embedded-C that combines intermittent execution fragments to form coherent sensing schedules---maintaining forward progress, data consistency, data freshness, and data utility across multiple power failures. Mayfly makes the passing of time explicit, binding data to the time it was gathered, and keeping track of data and time through power failures. We evaluated Mayfly against state-of-the art systems, conducted a user study, and implemented multiple real world applications across application domains in inventory tracking, and wearables.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"251 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134397202","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}
Extending battery lifetime is an important issue for mobile devices. While extensive attempts have been made at the software level, optimization often risks hampering user experience. One fundamental method to increase battery lifetime is to improve the efficiency of the battery itself. We argue that the multi-cell battery system, which is widely used for enhancing battery efficiency in the electric vehicle (EV) field, can solve this issue. However, due to the hardware constraints and device usage characteristics, battery advancements in the EV field are not directly applicable to mobile devices. In this paper, we propose BattMan, a multi-cell battery management system for mobile devices, for the enhancement of battery efficiency. We develop an accurate battery cell model to estimate the expected battery lifetime considering the recovery effect, the rate capacity effect, and battery aging. We also propose a multi-cell scheduling algorithm to maximize the overall battery lifetime. We implemented BattMan on recent smartphones and evaluated its impact on battery lifetime. The experimental results show that a two-cell configuration of the proposed system increases battery lifetime by an average of between 14-19%, depending on cell aging, in real usage scenarios over a single-cell battery of the same overall capacity. We hope the proposed multi-cell battery scheme opens up a new direction towards battery lifetime improvement in mobile devices.
{"title":"Exploiting Multi-Cell Battery for Mobile Devices: Design, Management, and Performance","authors":"Sungwoo Baek, Minyoung Go, Seokjun Lee, H. Cha","doi":"10.1145/3131672.3131684","DOIUrl":"https://doi.org/10.1145/3131672.3131684","url":null,"abstract":"Extending battery lifetime is an important issue for mobile devices. While extensive attempts have been made at the software level, optimization often risks hampering user experience. One fundamental method to increase battery lifetime is to improve the efficiency of the battery itself. We argue that the multi-cell battery system, which is widely used for enhancing battery efficiency in the electric vehicle (EV) field, can solve this issue. However, due to the hardware constraints and device usage characteristics, battery advancements in the EV field are not directly applicable to mobile devices. In this paper, we propose BattMan, a multi-cell battery management system for mobile devices, for the enhancement of battery efficiency. We develop an accurate battery cell model to estimate the expected battery lifetime considering the recovery effect, the rate capacity effect, and battery aging. We also propose a multi-cell scheduling algorithm to maximize the overall battery lifetime. We implemented BattMan on recent smartphones and evaluated its impact on battery lifetime. The experimental results show that a two-cell configuration of the proposed system increases battery lifetime by an average of between 14-19%, depending on cell aging, in real usage scenarios over a single-cell battery of the same overall capacity. We hope the proposed multi-cell battery scheme opens up a new direction towards battery lifetime improvement in mobile devices.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"28 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123871058","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}
M. Eichelberger, Kevin Luchsinger, Simon Tanner, Roger Wattenhofer
The standard method for outdoor localization is GPS, because it is globally available, relatively accurate and receivers are inexpensive. However, GPS does not work well indoors due to low signal strength. We explore a new localization approach, which uses the same principle as GPS localization, but employs signals transmitted by aircraft. Compared to GPS, aircraft signals are strong and can be received indoors. Our prototype implementation achieves a user localization accuracy of approximately 25 meters.
{"title":"Indoor Localization with Aircraft Signals","authors":"M. Eichelberger, Kevin Luchsinger, Simon Tanner, Roger Wattenhofer","doi":"10.1145/3131672.3131698","DOIUrl":"https://doi.org/10.1145/3131672.3131698","url":null,"abstract":"The standard method for outdoor localization is GPS, because it is globally available, relatively accurate and receivers are inexpensive. However, GPS does not work well indoors due to low signal strength. We explore a new localization approach, which uses the same principle as GPS localization, but employs signals transmitted by aircraft. Compared to GPS, aircraft signals are strong and can be received indoors. Our prototype implementation achieves a user localization accuracy of approximately 25 meters.","PeriodicalId":424262,"journal":{"name":"Proceedings of the 15th ACM Conference on Embedded Network Sensor Systems","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124519473","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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