Sensor networks are deemed suitable for large-scale deployments in the wild a variety of applications. In spite remarkable efforts community put to build sensor systems, an essential question still remains unclear at system level, motivating us explore answer from point real-world deployment view. Does wireless network really scale? We present findings operating system, GreenOrbs, with up 330 nodes deployed forest. instrument such throughout protocol stack and observations across layers...

In spite of the remarkable efforts community put to build sensor systems, an essential question still remains unclear at system level, motivating us explore answer from a point real-world deployment view. Does wireless network really scale? We present findings large scale operating system, GreenOrbs, with up 330 nodes deployed in forest. instrument such throughout protocol stack and observations across layers network. Based on our measurement, we propose make initial validate three...

Even though indoor smoking ban is being put into practice in civilized countries, existing vision or sensor-based detection methods cannot provide ubiquitous detection. In this paper, we take the first attempt to build a passive system, which leverages patterns leaves on WiFi signals identify activity even non-line-of-sight and through-wall environments. We study behaviors of smokers leverage common features recognize series motions during smoking, avoiding target-dependent training set...

LoRa, a representative Low-Power Wide Area Network (LPWAN) technology, has been shown as promising platform to connect Internet of Things. Practical LoRa deployments, however, suffer from collisions, especially in dense networks and wide coverage areas expected by applications. Existing collision resolution approaches do not exploit the coding properties thus cannot work well for low SNR signals. We propose NScale decompose concurrent transmissions leveraging subtle inter-packet time offsets...

LoRa, more generically Low-Power Wide Area Network (LPWAN), is a promising platform to connect Internet of Things. It enables low-cost low-power communication at few kbps over upto tens kilometers with 10-year battery lifetime. However, practical LPWAN deployments suffer from collisions, given the dense deployment devices and wide coverage area. We propose CoLoRa, protocol decompose large numbers concurrent transmissions one collision in LoRa networks. At heart we utilize packet time offset...

Low-Power Wide-Area Networks (LPWANs) are an emerging Internet-of-Things (IoT) paradigm marked by low-power and long-distance communication. Among them, LoRa is widely deployed for its unique characteristics open-source technology. By adopting the Chirp Spread Spectrum (CSS) modulation, enables low signal-to-noise ratio (SNR) However, standard demodulation method does not fully exploit properties of chirp signals, thus yields a sub-optimal SNR threshold under which decoding fails....

LoRa, as a representative Lower Power Wide Area Network (LPWAN) technology, shows great potential in providing low power and long range wireless communication. Real LoRa deployments, however, suffer from severe collisions. Existing collision decoding methods cannot work well for SNR signals. Most process collisions offline support real-time practice. To address these problems, we propose Pyramid, approach. the best of our knowledge, this is first multi-packet approach SNR. Pyramid exploits...

We study the ubiquitous data collection for mobile users in wireless sensor networks. People with handheld devices can easily interact network and collect data. propose a novel approach to network-wide The routing structure of is additively updated movement user. With this approach, we only perform local modification update while performance bounded controlled compared optimal performance. proposed protocol easy implement. Our analysis shows that scalable maintenance overheads, performs...

To save energy, wireless sensor networks often run in a low duty cycle mode, where the radios of nodes are scheduled between ON and OFF states. For to communicate with each other, Low Power Listening (LPL) Probing (LPP) two types rendezvous mechanisms. Nodes LPL or LPP rely on signal strength probe packets detect potential transmissions, then keep radio-on for communications. Unfortunately, many cases, susceptible interference, resulting undesirable radio time when interference is above...

Even though indoor smoking ban is being put into practice in civilized countries, existing vision or sensor-based detection methods cannot provide ubiquitous service. In this paper, we take the first attempt to build a passive system, Smokey, which leverages patterns leaves on WiFi signal identify activity even non-line-of-sight and through-wall environments. We study behaviors of smokers leverage common features recognize series motions during smoking, avoiding target-dependent training set...

LoRa has been shown as a promising platform for connecting large scale of Internet Things (IoT) devices, by providing low-power long-range communication with low data rate. different transmission parameters (e.g., power and spreading factor) to tradeoff noise resilience, range energy consumption environments. Thus, adjusting those is essential performance. Existing approaches are mainly threshold based fail achieve optimal efficiency. We propose DyLoRa, dynamic control system improve The...

Abstract Applications of localization range from body tracking, gesture capturing, indoor plan construction to mobile health sensing. Technologies such as inertial sensors, radio frequency signals and cameras have been deeply excavated locate targets. Among all the technologies, acoustic signal gains enormous favor considering its comparatively high accuracy with common infrastructure low time latency. Range-based falls into two categories: absolute relative range. Different mechanisms, Time...

LoRa backscatter is a promising technology to achieve low-power and long-distance communication for connecting millions of devices in the Internet Things. We present P2LoRa, first ambient system with parallel decoding long-range communication. The high level idea P2LoRa modulate data by shifting packets small frequency. To long distance communication, we enhance SNR signal concentrating leaked energy both frequency domain time domain. propose method accurately reconstruct cancel in-band...

This paper introduces ChirpTransformer, a versatile LoRa encoding framework that harnesses broad chirp features to dynamically modulate data, enhancing network coverage, throughput, and energy efficiency. Unlike the standard encoder offers only single configurable feature, our four distinct features, expanding spectrum of methods available for data modulation. To implement these on commercial off-the-shelf (COTS) nodes, we utilize combination software design hardware interrupt....

CitySee, an environment monitoring system with 1196 sensor nodes and 4 mesh in urban area, is mainly motivated by the needs of precise carbon emission measurement real-time surveillance for CO <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> management cities. Being one largest working wireless networks, CitySee faces several challenges such as hardware design, software development, platforms, network protocols, and, most important,...

Coexistence of Wi-Fi and ZigBee in 2.4 GHz ISM band is a long standing challenging problem. Previous solutions either require modifications current protocols or re-configurations, which not feasible large-scale wireless sensor networks. In this paper, we present WizBee, coexistence system using single-antenna sink without changing design. WizBee based on an observation that signal about 5 to 20 dB stronger than symmetric area, leaves much room for applying interference cancelation technique...

Motion tracking via Inertial Measurement Units (IMUs) on mobile and wearable devices has attracted significant interest in recent years. High-accuracy IMU-tracking can be applied various applications, such as indoor navigation, gesture recognition, text input, etc. Many efforts have been devoted to improving IMU-based motion the last two decades, from early calibration techniques ships or airplanes, arm models used smart devices. In this paper, we present a comprehensive survey We also...

LoRa, as a representative Low-Power Wide-Area Network (LPWAN) technology, can provide long-range communication for battery-powered IoT devices with 10-year lifetime. LoRa links in practice, however, experience high dynamics various environments. When the SNR falls below threshold (e.g., building), device disconnects from network. We propose Falcon, which addresses link by enabling data transmission very low or even disconnected links. At heart of we reveal that cannot deliver packets still...

LoRa, as a representative of Low Power Wide Area Network technology, has attracted significant attention from both academia and industry. However, the current understanding LoRa is far complete, implementations have large performance gap in SNR packet reception rate. This article presents comprehensive physical layer protocol (PHY) reveals fundamental reasons for gap. We present first full-stack PHY implementation with provable guarantee. enhance demodulation to work under extremely low (-20...

We study the ubiquitous data collection for mobile users in wireless sensor networks. People with handheld devices can easily interact network and collect data. propose a novel approach to network-wide The routing structure of is additively updated movement user. With this approach, we only perform limited modification update while performance bounded controlled compared optimal performance. proposed protocol easy implement. Our analysis shows that scalable maintenance overheads, performs...

We present a comprehensive delay performance measurement and analysis in large-scale wireless sensor network. build lightweight system robust method to calculate the per-packet delay. show that can identify incorrect delays recover them with bounded error. Through of other metrics, we seek answer following fundamental questions: What are spatial temporal characteristics real network? most important impacting factors, is there any practical model capture those factors? implications protocol...

Device-to-device communication is widely used for mobile devices and Internet of Things. Authentication key agreement are critical to build a secure channel between two devices. However, existing approaches often rely on pre-built fingerprint database suffer from low generation rate. We present GeneWave, fast device authentication protocol commodity GeneWave first achieves bidirectional initial based the physical response interval To keep accuracy estimation, we eliminate time uncertainty...

Video streaming takes up an increasing proportion of network traffic nowadays. Dynamic Adaptive Streaming over HTTP (DASH) becomes the de facto standard video and it is adopted by Youtube, Netflix, etc. Despite popularity, during shows identifiable pattern which brings threat to user privacy. In this paper, we propose a identification method using while streaming. Though there bitrate adaptation in DASH streaming, observe that trend remains relatively stable because widely used Variable...

LoRa has been shown as a promising Low-Power Wide Area Network (LPWAN) technology to connect millions of devices for the Internet Things by providing long-distance low-power communication in very low SNR. Real networks, however, suffer from severe packet collisions. Existing collision resolution approaches introduce high SNR loss, i.e., require much higher than LoRa. To push limit decoding, we present AlignTrack, first decoding approach that can work original Our key finding is chirp aligned...

UWB (Ultra-wideband) has been shown to be a promising technology provide accurate positioning for the Internet of Things. However, its performance significantly degrades in practice due Non-Line-Of-Sight (NLOS) issues. Various approaches have implicitly or explicitly explored problem. In this article, we propose RefLoc , which leverages unique benefits address NLOS While find that links can vary same environment, LOS possess similar features captured by high bandwidth UWB. Specifically,...