Gregor Dumphart

ETH Zurich

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Armin Wittneben

ETH Zurich

Henry Schulten

ETH Zurich

Klaus Witrisal

Graz University of Technology

Marc Kuhn

ZHAW Zurich University of Applied Sciences

Erik Leitinger

Graz University of Technology

Paul Meissner

Infineon Technologies (Austria)

Johannes Sager

ETH Zurich

Robert Heyn

ETH Zurich

Florian Trosch

Schindler (Switzerland)

Christoph Rüdisser

ETH Zurich

Cooperative Institutions

ETH Zurich

Graz University of Technology

Information Technology Laboratory

Signal Processing (United States)

Institut für Informationsverarbeitung

Applied Radar (United States)

École Polytechnique Fédérale de Lausanne

Christian Doppler Laboratory for Thermoelectricity

Infineon Technologies (Austria)

Ascom (Switzerland)

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Evaluation of Position-Related Information in Multipath Components for Indoor Positioning

IEEE Journal on Selected Areas in Communications (2015)

Erik Leitinger Paul Meissner Christoph Rüdisser Gregor Dumphart Klaus Witrisal

Location awareness is a key factor for a wealth of wireless indoor applications. Its provision requires the careful fusion of diverse information sources. For agents that use radio signals for localization, this information may either come from signal transmissions with respect to fixed anchors, from cooperative transmissions between agents, or from radar-like monostatic transmissions. Using a priori knowledge of a floor plan of the environment, specular multipath components can be exploited, based on a geometric-stochastic channel model. In this paper, a unified framework is presented for the quantification of this type of position-related information, using the concept of equivalent Fisher information. We derive analytical results for the Cramér-Rao lower bound of multipath-assisted positioning, considering bistatic transmissions between agents and fixed anchors, monostatic transmissions from agents, cooperative measurements between agents, and combinations thereof, including the effect of clock offsets. Awareness of this information enables highly accurate and robust indoor positioning. Computational results show the applicability of the framework for the characterization of the localization capabilities of a given environment, quantifying the influence of different system setups, signal parameters, and the impact of path overlap.

Position (finance)

Floor plan

10.1109/jsac.2015.2430520

Cite

Citations (139)

磁気誘導SISOおよびMIMOリンクのための確率的不整合モデル【Powered by NICT】

IEEE Conference Proceedings (2016)

Gregor Dumphart Wittneben Armin

Source

Cite

Citations (0)

Pairwise Distance and Position Estimators From Differences in UWB Channels to Observers

2022 IEEE Globecom Workshops (GC Wkshps) (2021)

Gregor Dumphart Robin Kramer Armin Wittneben

We consider the problem of obtaining relative location information between two wireless nodes from the differences in their ultra-wideband (UWB) channels to observer nodes. Our approach focuses on the delays of multipath components (MPCs) extracted from the observed channels. For the two different cases of known and unknown MPC association between these channels, we present estimators for the distance and for the relative position vector between the two nodes. The position estimators require both MPC directions and MPC delays as input. All presented estimators exhibit very desirable technological properties: they do not require line-of-sight conditions, precise synchronization, or knowledge about the observer locations or about the environment. These advantages could enable low-cost wireless network localization in dynamic multipath environments. The exposition is complemented by a numerical evaluation of the estimation accuracy using random sampling, where especially the position estimators show the potential for great accuracy.

Observer (physics)

Position (finance)

Non-line-of-sight propagation

10.1109/gcwkshps52748.2021.9682038

Cite

Citations (0)

The Channel Capacity of General Complex-Valued Load Modulation for Backscatter Communication

2022 IEEE Wireless Communications and Networking Conference (WCNC) (2022)

Gregor Dumphart Johannes Sager Armin Wittneben

This paper studies achievable information rates of backscatter communication systems where the tag performs load modulation with a freely adaptable passive termination. We find that the complex phasor of the tag current is constrained to a disk and that the capacity problem can therefore be described with existing results on peak-power-limited quadrature channels. This allows us to state the channel capacity and the capacityachieving distribution of the load impedance, which is described by non-concentric circles in the right half-plane. For the low-SNR case (SNR < 4.8 dB) we find that channel capacity is achieved by a purely reactive load with Cauchy-distributed reactance. The exposition is based on a system model that abstracts all relevant classes of backscatter communication systems, including RFID. To address practicality, we construct a symbol alphabet that allows for a near-capacity information rate of more than 6 bit per load-switching period at reasonably high SNR. We also find that the rate hardly decreases when typical value-range constraints are imposed on the load impedance.

10.1109/wcnc51071.2022.9771646

Cite

Citations (1)

Evaluation of Position-related Information in Multipath Components for Indoor Positioning

Erik Leitinger Paul Meissner Christoph Rüdisser Gregor Dumphart Klaus Witrisal

Location awareness is a key factor for a wealth of wireless indoor applications. Its provision requires the careful fusion of diverse information sources. For agents that use radio signals for localization, this information may either come from signal transmissions with respect to fixed anchors, from cooperative transmissions inbetween agents, or from radar-like monostatic transmissions. Using a-priori knowledge of a floor plan of the environment, specular multipath components can be exploited, based on a geometric-stochastic channel model. In this paper, a unified framework is presented for the quantification of this type of position-related information, using the concept of equivalent Fisher information. We derive analytical results for the Cramer-Rao lower bound of multipath-assisted positioning, considering bistatic transmissions between agents and fixed anchors, monostatic transmissions from agents, cooperative measurements inbetween agents, and combinations thereof, including the effect of clock offsets. Awareness of this information enables highly accurate and robust indoor positioning. Computational results show the applicability of the framework for the characterization of the localization capabilities of a given environment, quantifying the influence of different system setups, signal parameters, and the impact of path overlap.

Position (finance)

Floor plan

Cite

Citations (0)

Magneto-inductive passive relaying in arbitrarily arranged networks

Gregor Dumphart Eric Slottke Armin Wittneben

We consider a wireless sensor network that uses inductive near-field coupling for wireless powering or communication, or for both. The severely limited range of an inductively coupled source-destination pair can be improved using resonant relay devices, which are purely passive in nature. Utilization of such magneto-inductive relays has only been studied for regular network topologies, allowing simplified assumptions on the mutual antenna couplings. In this work we present an analysis of magneto-inductive passive relaying in arbitrarily arranged networks. We find that the resulting channel has characteristics similar to multipath fading: the channel power gain is governed by a non-coherent sum of phasors, resulting in increased frequency selectivity. We propose and study two strategies to increase the channel power gain of random relay networks: i) deactivation of individual relays by open-circuit switching and ii) frequency tuning. The presented results show that both methods improve the utilization of available passive relays, leading to reliable and significant performance gains.

Inductive coupling

10.1109/icc.2017.7997344

Cite

Citations (10)

Evaluation of Position-related Information in Multipath Components for Indoor Positioning

arXiv (Cornell University) (2014)

Erik Leitinger Paul Meissner Christoph Rüdisser Gregor Dumphart Klaus Witrisal

Location awareness is a key factor for a wealth of wireless indoor applications. Its provision requires the careful fusion of diverse information sources. For agents that use radio signals for localization, this information may either come from signal transmissions with respect to fixed anchors, from cooperative transmissions inbetween agents, or from radar-like monostatic transmissions. Using a-priori knowledge of a floor plan of the environment, specular multipath components can be exploited, based on a geometric-stochastic channel model. In this paper, a unified framework is presented for the quantification of this type of position-related information, using the concept of equivalent Fisher information. We derive analytical results for the Cram\'er-Rao lower bound of multipath-assisted positioning, considering bistatic transmissions between agents and fixed anchors, monostatic transmissions from agents, cooperative measurements inbetween agents, and combinations thereof, including the effect of clock offsets. Awareness of this information enables highly accurate and robust indoor positioning. Computational results show the applicability of the framework for the characterization of the localization capabilities of a given environment, quantifying the influence of different system setups, signal parameters, and the impact of path overlap.

Position (finance)

Floor plan

10.48550/arxiv.1409.1467

Cite

Citations (1)

Stochastic misalignment model for magneto-inductive SISO and MIMO links

IEEE Conference Proceedings (2016)

Gregor Dumphart Wittneben Armin

Magneto

Source

Cite

Citations (0)

User Tracking for Access Control with Bluetooth Low Energy

2022 IEEE 95th Vehicular Technology Conference: (VTC2022-Spring) (2019)

Robert Heyn Marc Kuhn Henry Schulten Gregor Dumphart Janick Zwyssig

The Received Signal Strength Indicator (RSSI) of Bluetooth Low Energy (BLE) is a popular means for indoor user localization and tracking as it reflects the transmitter-receiver distance and is readily available in all current smartphones. Since fading, shadowing and antenna patterns cause severe RSSI fluctuations, many RSSI-based localization systems use fingerprinting instead of parameter estimation based on a channel model (e.g. trilateration from distance estimates). Fingerprinting however requires a large effort for training data acquisition and frequent updates in dynamic environments. In this paper we focus on wireless access control with BLE. We demonstrate that a practical implementation of such a tracking system can meet the typical demands of generic access control problems with low- complexity parameter estimation techniques, namely trilateration and optional Kalman filtering. Thereby, satisfactory accuracy is enabled by diversity (averaging in space, time and frequency), calibration and appropriate observation space modeling. We find that including the RSSI directly in the observation space renders trilateration obsolete, which reduces complexity even further.

Bluetooth Low Energy

Tracking (education)

10.1109/vtcspring.2019.8746465

Cite

Citations (6)

Load Modulation for Backscatter Communication: Channel Capacity and Near-Capacity Schemes

IEEE Transactions on Wireless Communications (2023)

Gregor Dumphart Johannes Sager Armin Wittneben

In backscatter communication (BC), a passive tag transmits information by just affecting an external electromagnetic field through load modulation. Thereby, the feed current of the excited tag antenna is modulated by adapting the passive termination load. This paper studies the achievable information rates with a freely adaptable passive load. As a prerequisite, we unify monostatic, bistatic, and ambient BC with circuit-based system modeling. We present the crucial insight that channel capacity is described by existing results on peak-power-limited quadrature Gaussian channels, because the steady-state tag current phasor lies on a disk. Consequently, we derive the channel capacity for the case of an unmodulated external field, for general passive, purely reactive, or purely resistive tag loads. We find that modulating both resistance and reactance is important for very high rates. We discuss the capacity-achieving load statistics, rate asymptotics, technical conclusions, and rate losses from value-range-constrained loads (which are found to be small for moderate constraints). We then demonstrate that near-capacity rates can be attained by more practical schemes: (i) amplitude-and-phase-shift keying on the reflection coefficient and (ii) simple load circuits of a few switched resistors and capacitors. Finally, we draw conclusions for the ambient BC channel capacity in important special cases.

Reflection coefficient

10.1109/twc.2023.3313110

Cite

Citations (1)