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Theodore S. Rappaport

Bio: Theodore S. Rappaport is an academic researcher from New York University. The author has contributed to research in topics: Path loss & Multipath propagation. The author has an hindex of 112, co-authored 490 publications receiving 68853 citations. Previous affiliations of Theodore S. Rappaport include University of Waterloo & University of Texas at Austin.


Papers
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Patent
26 Feb 2016
TL;DR: In this article, the authors present a receiver configured to receive a first signal from the channel, generate a second signal, and measure the parameter based on a comparison between the first and second signals.
Abstract: Exemplary systems and methods can be provided for measuring a parameter—e.g., channel impulse response and/or power delay profile—of a wideband, millimeter-wave (mmW) channel. The exemplary systems can include a receiver configured to receive a first signal from the channel, generate a second signal, and measure the parameter based on a comparison between the first and second signals; and a controller configured to determine first and second calibration of the system before and after measuring the parameter, and determine a correction for the parameter measurement based on the first and second calibrations. Exemplary methods can also be provided for calibrating a system for measuring the channel parameter. Such methods can be utilized for systems in which the TX and RX devices share a common frequency source and for systems in which the TX and RX devices have individual frequency sources that free-run during channel measurements.

17 citations

Proceedings ArticleDOI
01 Dec 2011
TL;DR: A parametric study is provided that shows how the analysis can be used to optimize spectral efficiency, and how to adjust an operating link set point for an operational signal-noise-ratio that achieves optimum data rates for a given consumed power level.
Abstract: In this paper, we present a universal figure of merit, the Consumption Factor (CF), that may be used to judge the power efficiency of any communications device or link. We derive expressions for the CF that account for the power efficiency of components in a homodyne transmitter, as this transmitter architecture will typify many future mm-Wave and massively broadband™ systems [1]. The CF is defined as the maximum ratio of data rate to consumed power as a function of the transceiver subsystem and channel parameters, and offers a way for circuit designers and communication engineers to optimize and compare designs of different radios. We show also how CF may be extended to other transmitter architectures beyond the homodyne architecture. As "green radios" and higher efficiency wireless devices become critical for the reduction of wasted power and improved battery life in very broadband communication systems, the analysis presented here gives a mathematical framework from which comparison and optimization of transmitter-receiver designs can be performed. This paper also provides a parametric study that shows how the analysis can be used to optimize spectral efficiency, and how to adjust an operating link set point for an operational signal-noise-ratio that achieves optimum data rates for a given consumed power level. The new methodology shows how the efficiencies and gains of different components in a radio circuit impact the CF, including antennas, power amplifiers, and mixers. The results show that the efficiency of components on the signal path of a transmitter closest to the point at which information is transmitted, such as the antenna, have the greatest impact on the CF. A follow-on study will show the impact of receiver components and channel conditions on the CF.

17 citations

Proceedings ArticleDOI
20 Nov 2019
TL;DR: In this article, the authors proposed a fully-digital direct-conversion array receiver at 28 GHz. The design consists of a custom 28 GHz patch antenna sub-array providing gain in the elevation plane, with azimuthal plane beamforming provided by real-time digital signal processing (DSP) algorithms running on a Xilinx Radio Frequency System on Chip (RF SoC).
Abstract: This paper discusses early results associated with a fully-digital direct-conversion array receiver at 28 GHz. The proposed receiver makes use of commercial off-the-shelf (COTS) electronics, including the receiver chain. The design consists of a custom 28 GHz patch antenna sub-array providing gain in the elevation plane, with azimuthal plane beamforming provided by real-time digital signal processing (DSP) algorithms running on a Xilinx Radio Frequency System on Chip (RF SoC). The proposed array receiver employs element-wise fully-digital array processing that supports ADC sample rates up to 2 GS/second and up to 1 GHz of operating bandwidth per antenna. The RF mixed-signal data conversion circuits and DSP algorithms operate on a single-chip RFSoC solution installed on the Xilinx ZCU1275 prototyping platform.

17 citations

Proceedings ArticleDOI
15 Jun 1988
TL;DR: The data show that excess mean delay, RMS delay spread, and time-delay jitter values in single-storey factory buildings are similar to values observed in and around multistorey office buildings.
Abstract: The results of wideband delay spread and time-delay jitter measurements collected from five factory buildings are presented. Carrier frequency was 1282 MHz. The data show that excess mean delay, RMS delay spread, and time-delay jitter values in single-storey factory buildings are similar to values observed in and around multistorey office buildings. Differential time-delay jitter measurements reveal that the excess mean delay can vary by as much as 180 ns for 5.5-cm shifts in receiver location. Results from 950 multipath power delay profiles collected in 50 local areas are summarized. >

16 citations

Proceedings ArticleDOI
01 Dec 2010
TL;DR: A novel analysis is provided that uses a superposition model for multipath energy and derive a closed-form expression that relates ADC resolution to the channel state, and also the bit error rate for MQAM constellations.
Abstract: Multi-gigabit per second wireless network devices are emerging for personal area networks (PAN) in the 60 GHz band. Such devices are typically power hungry, largely due to the requisite high speed analog to digital converters (ADCs) that can consume from tens to hundreds of milliwatts of power. This paper studies the use of analog equalization before the ADC to reduce the required ADC resolution. We provide a novel analysis that uses a superposition model for multipath energy and derive a closed-form expression that relates ADC resolution to the channel state, and also the bit error rate (BER) for MQAM constellations. Simulations verify that analog equalization can reduce the link bit-error rate by up to several orders of magnitude, without increasing the number of quantization bits in the ADC.

16 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: The concept of sensor networks which has been made viable by the convergence of micro-electro-mechanical systems technology, wireless communications and digital electronics is described.

17,936 citations

Journal ArticleDOI
TL;DR: Using distributed antennas, this work develops and analyzes low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks and develops performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading.
Abstract: We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space diversity available through cooperating terminals' relaying signals for one another. We outline several strategies employed by the cooperating radios, including fixed relaying schemes such as amplify-and-forward and decode-and-forward, selection relaying schemes that adapt based upon channel measurements between the cooperating terminals, and incremental relaying schemes that adapt based upon limited feedback from the destination terminal. We develop performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading, focusing on the high signal-to-noise ratio (SNR) regime. Except for fixed decode-and-forward, all of our cooperative diversity protocols are efficient in the sense that they achieve full diversity (i.e., second-order diversity in the case of two terminals), and, moreover, are close to optimum (within 1.5 dB) in certain regimes. Thus, using distributed antennas, we can provide the powerful benefits of space diversity without need for physical arrays, though at a loss of spectral efficiency due to half-duplex operation and possibly at the cost of additional receive hardware. Applicable to any wireless setting, including cellular or ad hoc networks-wherever space constraints preclude the use of physical arrays-the performance characterizations reveal that large power or energy savings result from the use of these protocols.

12,761 citations

Journal ArticleDOI
Simon Haykin1
TL;DR: Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks: radio-scene analysis, channel-state estimation and predictive modeling, and the emergent behavior of cognitive radio.
Abstract: Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind: /spl middot/ highly reliable communication whenever and wherever needed; /spl middot/ efficient utilization of the radio spectrum. Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks. 1) Radio-scene analysis. 2) Channel-state estimation and predictive modeling. 3) Transmit-power control and dynamic spectrum management. This work also discusses the emergent behavior of cognitive radio.

12,172 citations

Journal ArticleDOI
TL;DR: This work develops and analyzes low-energy adaptive clustering hierarchy (LEACH), a protocol architecture for microsensor networks that combines the ideas of energy-efficient cluster-based routing and media access together with application-specific data aggregation to achieve good performance in terms of system lifetime, latency, and application-perceived quality.
Abstract: Networking together hundreds or thousands of cheap microsensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. These networks require robust wireless communication protocols that are energy efficient and provide low latency. We develop and analyze low-energy adaptive clustering hierarchy (LEACH), a protocol architecture for microsensor networks that combines the ideas of energy-efficient cluster-based routing and media access together with application-specific data aggregation to achieve good performance in terms of system lifetime, latency, and application-perceived quality. LEACH includes a new, distributed cluster formation technique that enables self-organization of large numbers of nodes, algorithms for adapting clusters and rotating cluster head positions to evenly distribute the energy load among all the nodes, and techniques to enable distributed signal processing to save communication resources. Our results show that LEACH can improve system lifetime by an order of magnitude compared with general-purpose multihop approaches.

10,296 citations