An RF-Based Positioning Method for Tracing a Cluster of Moving Scatterers in Non-Stationary Indoor Environments

Author's accepted manuscript© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This letter presents a novel iterative positioning method for tracing the body segments of a person moving indoors using radio-frequency (RF) signals. The indoor space is equipped with a multiple-input multiple-output (MIMO) communication system. The person is modelled by a cluster of moving point scatterers, playing the role of moving body segments. The proposed technique estimates the time-variant (TV) positions of the moving scatterers by fitting the TV channel transfer function (TVCTF) of the channel model as close as possible to the TVCTF of the measured channels. Numerical results are presented to demonstrate the accuracy of this method.acceptedVersio

A non-stationary relay-based 3D MIMO channel model with time-variant path gains for human activity recognition in indoor environments

Extensive research showed that the physiological response of human tissue to exposure to low-frequency electromagnetic fields is the induction of an electric current in the body segments. As a result, each segment of the human body behaves as a relay, which retransmits the radio-frequency (RF) signal. To investigate the impact of this phenomenon on the Doppler characteristics of the received RF signal, we introduce a new three-dimensional (3D) non-stationary channel model to describe the propagation phenomenon taking place in an indoor environment. Here, the indoor space is equipped with a multiple-input multiple-output (MIMO) system. A single person is moving in the indoor space and is modelled by a cluster of synchronized moving point scatterers, which behave as relays. We derive the time-variant (TV) channel transfer function (CTF) with TV path gains and TV path delays. The expression of the TV path gains is obtained from the instantaneous total received power at the receiver side. This TV total received power is expressed as the product of the TV power of the RF signal initially transmitted and received by a body segment and the TV received power of the redirected signal. These TV powers are determined according the free-space path-loss model. Also, a closed-form approximate solution to the spectrogram of the TVCTF is derived. Here, we analyse the effect of the motion of the person and the validity of the relay assumption on the spectrogram, the TV mean Doppler shift (MDS), and the TV Doppler shift (DS) of the TVCTF. Simulation results are presented to illustrate the proposed channel model.publishedVersio

CDMA, OFDM, MC-CDMA, quel choix pour une voie descendante ?

Cet article propose une démarche comparative de différentes formes d'onde candidates pour une voie descendante de radiocommunications. Partant d'un formalisme général pour le DS-CDMA, l'OFDM et le MC-CDMA, les comportements de ces formes d'onde vis à vis d'erreurs de fréquence ou de bruit de phase sont analysés

Estimation of the Velocity of a Walking Person in Indoor Environments from mmWave Signals

accepted versionNivå

Estimation of the Velocity of a Walking Person in Non-Stationary Indoor Environments from the Received RF Signal

acceptedVersionNivå

A Geometry-Based Underwater Acoustic Channel Model Allowing for Sloped Ocean Bottom Conditions

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OFDM and CDMA, unified approach and channel-matched spreading codes generation algorithm

In this paper TDMA, CDMA, MC-CDMA and OFDM are presented through an unified formalism. The cyclic prefix insertion is extended to all approaches presented and not only restricted to OFDM. Many fundamental results are highlighted. It is for example shown that if we are looking for a family of orthogonal spreading sequences being yet orthogonal after a one chip delay then we have not another choice than OFDM. Different kind of receivers, involving a same « channel » matrix, are presented : OFDM receiver, Rake receiver and MMSE receiver. All these receivers involve a same channel matrix representing the effect of the propagation channel, the cyclic prefix insertion and its suppression. Finally an algorithm for generating spreading sequences matched to a given propagation channel is introduced. Spreading sequences generated having unequal transmission properties, a power and modulation allocation algorithm is introduced for them. Performances obtained are then very close to those obtained through the OFDM approach.Cet article s'appuie sur un formalisme matriciel qui permet de présenter les approches TDMA, CDMA, MC-CDMA et OFDM de manière unifiée. La formalisation généralise l'emploi du préfixe cyclique, initialement réservé à l'OFDM, à toutes ces approches. Elle permet de mettre en lumière plusieurs résultats fondamentaux de manière très rapide. On montre ainsi que si l'on cherche des séquences d'étalement CDMA qui sont orthogonales et dont l'orthogonalité résiste à une imprécision temporelle d'un élément de la séquence alors, obligatoirement, ces séquences sont les sinusoïdes complexes utilisées en OFDM. On développe ensuite les différentes formes possibles des récepteurs. Le récepteur MMSE, le récepteur RAKE et le récepteur classiquement utilisé dans le cas de l'OFDM sont exprimés en faisant intervenir une même matrice « canal » qui intègre à elle seule l'insertion du préfixe cyclique, la convolution par la réponse impulsionnelle du canal et la suppression du préfixe cyclique. Enfin, dans le cas d'un canal connu, on introduit une méthode de conception de séquences d'étalement adaptées au canal. Les séquences de cette famille affichant des performances de transmission inégales, on propose alors de leur appliquer, comme on le fait pour l'OFDM, un algorithme d'allocation de puissances d'émission et de schémas de modulation. On montre alors que les performances de transmission obtenues sont comparables à celles de l'OFDM

Adult Low-Hypodiploid Acute Lymphoblastic Leukemia Emerges from Preleukemic TP53-Mutant Clonal Hematopoiesis

UNLABELLED Low hypodiploidy defines a rare subtype of B-cell acute lymphoblastic leukemia (B-ALL) with a dismal outcome. To investigate the genomic basis of low-hypodiploid ALL (LH-ALL) in adults, we analyzed copy-number aberrations, loss of heterozygosity, mutations, and cytogenetics data in a prospective cohort of Philadelphia (Ph)-negative B-ALL patients (n = 591, ages 18-84 years), allowing us to identify 80 LH-ALL cases (14%). Genomic analysis was critical for evidencing low hypodiploidy in many cases missed by cytogenetics. The proportion of LH-ALL within Ph-negative B-ALL dramatically increased with age, from 3% in the youngest patients (under 40 years old) to 32% in the oldest (over 55 years old). Somatic TP53 biallelic inactivation was the hallmark of adult LH-ALL, present in virtually all cases (98%). Strikingly, we detected TP53 mutations in posttreatment remission samples in 34% of patients. Single-cell proteogenomics of diagnosis and remission bone marrow samples evidenced a preleukemic, multilineage, TP53-mutant clone, reminiscent of age-related clonal hematopoiesis. SIGNIFICANCE We show that low-hypodiploid ALL is a frequent entity within B-ALL in older adults, relying on somatic TP53 biallelic alteration. Our study unveils a link between aging and low-hypodiploid ALL, with TP53-mutant clonal hematopoiesis representing a preleukemic reservoir that can give rise to aneuploidy and B-ALL. See related commentary by Saiki and Ogawa, p. 102. This article is highlighted in the In This Issue feature, p. 101

Characteristics and outcome of patients with low-/intermediate-risk acute promyelocytic leukemia treated with arsenic trioxide - an international collaborative study

The aim of this study was to characterize a large series of 154 patients with acute promyelocytic leukemia (APL; median age, 53 years; range, 18-90 years) and evaluate real-life outcome after up-front treatment with arsenic trioxide (ATO) and alltrans retinoic acid (ATRA). All patients were included in the prospective NAPOLEON registry (NCT02192619) between 2013 and 2019. APL was de novo in 91% (n=140) and therapy-related in 9% (n=14); 13% (n=20) were older than 70 years. At diagnosis bleeding/hemorrhage was present in 38% and thrombosis in 3%. Complete remission was achieved in 152 patients (99%), whereas two patients (1%) experienced induction death within 18 days after start of therapy. With a median follow-up of 1.99 years (95%-CI, 1.61-2.30 years) 1-year and 2-years overall survival (OS) rates were 97% (95%-CI, 94-100%) and 95% (95%-CI, 91-99%), respectively. Age above 70 years was associated with a significantly shorter OS (P<0.001) as compared to younger patients. So far no relapses were observed. Six patients (4%) died in CR after in median 0.95 years after diagnosis (range, 0.18-2.38 years). Our data confirm the efficiency and durability of ATO/ATRA in the primary management of adult low-/ intermediate-risk APL patients in the real life setting, irrespective of age