441 research outputs found
Implementation Aspects of a Transmitted-Reference UWB Receiver
In this paper, we discuss the design issues of an ultra wide band (UWB) receiver targeting a single-chip CMOS implementation for low data-rate applications like ad hoc wireless sensor networks. A non-coherent transmitted reference (TR) receiver is chosen because of its small complexity compared to other architectures. After a brief recapitulation of the UWB fundamentals and a short discussion on the major differences between coherent and non-coherent receivers, we discuss issues, challenges and possible design solutions. Several simulation results obtained by means of a behavioral model are presented, together with an analysis of the trade-off between performance and complexity in an integrated circuit implementation
An effective AMS Top-Down Methodology Applied to the Design of a Mixed-SignalUWB System-on-Chip
The design of Ultra Wideband (UWB) mixed-signal SoC for localization applications in wireless personal area networks is currently investigated by several researchers. The complexity of the design claims for effective top-down methodologies. We propose a layered approach based on VHDL-AMS for the first design stages and on an intelligent use of a circuit-level simulator for the transistor-level phase. We apply the latter just to one block at a time and wrap it within the system-level VHDL-AMS description. This method allows to capture the impact of circuit-level design choices and non-idealities on system performance. To demonstrate the effectiveness of the methodology we show how the refinement of the design affects specific UWB system parameters such as bit-error rate and localization estimations
A VHDL-AMS Simulation Environment for an UWB Impulse Radio Transceiver
Ultra-Wide-Band (UWB) communication based on the impulse radio paradigm is becoming increasingly popular. According to the IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a, UWB will play a major role in localization applications, due to the high time resolution of UWB signals which allow accurate indirect measurements of distance between transceivers. Key for the successful implementation of UWB transceivers is the level of integration that will be reached, for which a simulation environment that helps take appropriate design decisions is crucial. Owing to this motivation, in this paper we propose a multiresolution UWB simulation environment based on the VHDL-AMS hardware description language, along with a proper methodology which helps tackle the complexity of designing a mixed-signal UWB System-on-Chip. We applied the methodology and used the simulation environment for the specification and design of an UWB transceiver based on the energy detection principle. As a by-product, simulation results show the effectiveness of UWB in the so-called ranging application, that is the accurate evaluation of the distance between a couple of transceivers using the two-way-ranging metho
Smart Sensor Networks For Sensor-Neural Interface
One in every fifty Americans suffers from paralysis, and approximately 23% of paralysis cases are caused by spinal cord injury. To help the spinal cord injured gain functionality of their paralyzed or lost body parts, a sensor-neural-actuator system is commonly used. The system includes: 1) sensor nodes, 2) a central control unit, 3) the neural-computer interface and 4) actuators. This thesis focuses on a sensor-neural interface and presents the research related to circuits for the sensor-neural interface.
In Chapter 2, three sensor designs are discussed, including a compressive sampling image sensor, an optical force sensor and a passive scattering force sensor. Chapter 3 discusses the design of the analog front-end circuit for the wireless sensor network system. A low-noise low-power analog front-end circuit in 0.5ÎĽm CMOS technology, a 12-bit 1MS/s successive approximation register (SAR) analog-to-digital converter (ADC) in 0.18ÎĽm CMOS process and a 6-bit asynchronous level-crossing ADC realized in 0.18ÎĽm CMOS process are presented. Chapter 4 shows the design of a low-power impulse-radio ultra-wide-band (IR-UWB) transceiver (TRx) that operates at a data rate of up to 10Mbps, with a power consumption of 4.9pJ/bit transmitted for the transmitter and 1.12nJ/bit received for the receiver. In Chapter 5, a wireless fully event-driven electrogoniometer is presented. The electrogoniometer is implemented using a pair of ultra-wide band (UWB) wireless smart sensor nodes interfacing with low power 3-axis accelerometers. The two smart sensor nodes are configured into a master node and a slave node, respectively. An experimental scenario data analysis shows higher than 90% reduction of the total data throughput using the proposed fully event-driven electrogoniometer to measure joint angle movements when compared with a synchronous Nyquist-rate sampling system.
The main contribution of this thesis includes: 1) the sensor designs that emphasize power efficiency and data throughput efficiency; 2) the fully event-driven wireless sensor network system design that minimizes data throughput and optimizes power consumption
Self-sustaining Ultra-wideband Positioning System for Event-driven Indoor Localization
Smart and unobtrusive mobile sensor nodes that accurately track their own
position have the potential to augment data collection with location-based
functions. To attain this vision of unobtrusiveness, the sensor nodes must have
a compact form factor and operate over long periods without battery recharging
or replacement. This paper presents a self-sustaining and accurate
ultra-wideband-based indoor location system with conservative infrastructure
overhead. An event-driven sensing approach allows for balancing the limited
energy harvested in indoor conditions with the power consumption of
ultra-wideband transceivers. The presented tag-centralized concept, which
combines heterogeneous system design with embedded processing, minimizes idle
consumption without sacrificing functionality. Despite modest infrastructure
requirements, high localization accuracy is achieved with error-correcting
double-sided two-way ranging and embedded optimal multilateration. Experimental
results demonstrate the benefits of the proposed system: the node achieves a
quiescent current of and operates at while performing
energy harvesting and motion detection. The energy consumption for position
updates, with an accuracy of (2D) in realistic non-line-of-sight
conditions, is . In an asset tracking case study within a
multi-room office space, the achieved accuracy level allows for identifying 36
different desk and storage locations with an accuracy of over . The
system`s long-time self-sustainability has been analyzed over in
multiple indoor lighting situations
Slocalization: Sub-{\mu}W Ultra Wideband Backscatter Localization
Ultra wideband technology has shown great promise for providing high-quality
location estimation, even in complex indoor multipath environments, but
existing ultra wideband systems require tens to hundreds of milliwatts during
operation. Backscatter communication has demonstrated the viability of
astonishingly low-power tags, but has thus far been restricted to narrowband
systems with low localization resolution. The challenge to combining these
complimentary technologies is that they share a compounding limitation,
constrained transmit power. Regulations limit ultra wideband transmissions to
just -41.3 dBm/MHz, and a backscatter device can only reflect the power it
receives. The solution is long-term integration of this limited power, lifting
the initially imperceptible signal out of the noise. This integration only
works while the target is stationary. However, stationary describes the vast
majority of objects, especially lost ones. With this insight, we design
Slocalization, a sub-microwatt, decimeter-accurate localization system that
opens a new tradeoff space in localization systems and realizes an energy,
size, and cost point that invites the localization of every thing. To evaluate
this concept, we implement an energy-harvesting Slocalization tag and find that
Slocalization can recover ultra wideband backscatter in under fifteen minutes
across thirty meters of space and localize tags with a mean 3D Euclidean error
of only 30 cm.Comment: Published at the 17th ACM/IEEE Conference on Information Processing
in Sensor Networks (IPSN'18
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