scholarly journals Securing the Insecure: A First-Line-of-Defense for Body-Centric Nanoscale Communication Systems Operating in THz Band

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3534
Author(s):  
Waqas Aman ◽  
Muhammad Mahboob Ur Rahman ◽  
Hasan T. Abbas ◽  
Muhammad Arslan Khalid ◽  
Muhammad A. Imran ◽  
...  
Keyword(s):  
False Alarm ◽  
Hypothesis Testing ◽  
Communication Systems ◽  
Viterbi Algorithm ◽  
Path Loss ◽  
Attack Detection ◽  
Testing Device ◽  
True Path ◽  
Nano Sensors ◽  
Propagation Medium

This manuscript presents a novel mechanism (at the physical layer) for authentication and transmitter identification in a body-centric nanoscale communication system operating in the terahertz (THz) band. The unique characteristics of the propagation medium in the THz band renders the existing techniques (say for impersonation detection in cellular networks) not applicable. In this work, we considered a body-centric network with multiple on-body nano-senor nodes (of which some nano-sensors have been compromised) who communicate their sensed data to a nearby gateway node. We proposed to protect the transmissions on the link between the legitimate nano-sensor nodes and the gateway by exploiting the path loss of the THz propagation medium as the fingerprint/feature of the sender node to carry out authentication at the gateway. Specifically, we proposed a two-step hypothesis testing mechanism at the gateway to counter the impersonation (false data injection) attacks by malicious nano-sensors. To this end, we computed the path loss of the THz link under consideration using the high-resolution transmission molecular absorption (HITRAN) database. Furthermore, to refine the outcome of the two-step hypothesis testing device, we modeled the impersonation attack detection problem as a hidden Markov model (HMM), which was then solved by the classical Viterbi algorithm. As a bye-product of the authentication problem, we performed transmitter identification (when the two-step hypothesis testing device decides no impersonation) using (i) the maximum likelihood (ML) method and (ii) the Gaussian mixture model (GMM), whose parameters are learned via the expectation–maximization algorithm. Our simulation results showed that the two error probabilities (missed detection and false alarm) were decreasing functions of the signal-to-noise ratio (SNR). Specifically, at an SNR of 10 dB with a pre-specified false alarm rate of 0.2, the probability of correct detection was almost one. We further noticed that the HMM method outperformed the two-step hypothesis testing method at low SNRs (e.g., a 10% increase in accuracy was recorded at SNR = −5 dB), as expected. Finally, it was observed that the GMM method was useful when the ground truths (the true path loss values for all the legitimate THz links) were noisy.

scholarly journals Spatial characterization of propagation channels for terahertz band

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Bilal Aghoutane ◽  
Mohammed El Ghzaoui ◽  
Hanan El Faylali
Keyword(s):  
Communication Systems ◽  
Indoor Environment ◽  
Channel Model ◽  
Path Loss ◽  
Propagation Loss ◽  
Terahertz Band ◽  
Indoor Scenarios ◽  
Transmission Windows ◽  
Sv Channel

AbstractThe aim of this work consists in characterizing the Terahertz (THz) propagation channel in an indoor environment, in order to propose a channel model for THz bands. We first described a propagation loss model by taking into account the attenuation of the channel as a function of distance and frequency. The impulse response of the channel is then described by a set of rays, characterized by their amplitude, their delay and their phase. Apart from the frequency selective nature, path loss in THz band is also an others issue associated with THz communication systems. This work based on the conventional Saleh-Valenzuela (SV) model which is intended for indoor scenarios. In this paper, we have introduced random variables as Line of sight (LOS) component, and then merging it with the SV channel model to adopt it to the THz context. From simulation, we noted an important effect when the distance between the transmitter and the receiver change. This effect produces variations in frequency loss. The simulations carried out from this model show that to enhance the performance of THz system it is recommended to transmit information over transmission windows instead over the whole band.

scholarly journals Broadband Wireless Channel in Composite High-Speed Railway Scenario: Measurements, Simulation, and Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Jianwen Ding ◽  
Lei Zhang ◽  
Jingya Yang ◽  
Bin Sun ◽  
Jiying Huang
Keyword(s):  
Ray Tracing ◽  
Communication Systems ◽  
High Speed ◽  
Channel Model ◽  
High Reliability ◽  
Rapid Development ◽  
Path Loss ◽  
Wireless Channel ◽  
Delay Spread ◽  
High Speed Railway

The rapid development of high-speed railway (HSR) and train-ground communications with high reliability, safety, and capacity promotes the evolution of railway dedicated mobile communication systems from Global System for Mobile Communications-Railway (GSM-R) to Long Term Evolution-Railway (LTE-R). The main challenges for LTE-R network planning are the rapidly time-varying channel and high mobility, because HSR lines consist of a variety of complex terrains, especially the composite scenarios where tunnels, cuttings, and viaducts are connected together within a short distance. Existing researches mainly focus on the path loss and delay spread for the individual HSR scenarios. In this paper, the broadband measurements are performed using a channel sounder at 950 MHz and 2150 MHz in a typical HSR composite scenario. Based on the measurements, the pivotal characteristics are analyzed for path loss exponent, power delay profile, and tap delay line model. Then, the deterministic channel model in which the 3D ray-tracing algorithm is applied in the composite scenario is presented and validated by the measurement data. Based on the ray-tracing simulations, statistical analysis of channel characteristics in delay and Doppler domain is carried out for the HSR composite scenario. The research results can be useful for radio interface design and optimization of LTE-R system.

scholarly journals ANALISIS PROPAGASI PADA KAWASAN KAMPUS UNIVERSITAS NUSA CENDANA PENFUI KUPANG

2019 ◽  
pp. 7-16
Author(s):  
Leonardo F. Lay ◽  
Kalvein Rantelobo ◽  
Beby H. A. Manafe
Keyword(s):  
Communication Systems ◽  
Cost Model ◽  
Path Loss ◽  
Secondary Data ◽  
Propagation Model ◽  
Primary Data ◽  
Acceptance Test ◽  
Test Drive ◽  
Dry Land ◽  
The University

In a telecommunications system, a radio propagation model is needed to do a design, construction, and development of mobile communication systems. Propagation models commonly used are the Okumura-Hatta model and the COST model 231. These models are used to determine an accurate propagation model in a particular area. This study aims to obtain a propagation model on the environmental conditions of dry-land such as the University of Nusa Cendana areas by using Okumura-Hata path loss modeling and COST-231. In this study, the acceptance test drive was carried out at frequencies of 900 Mhz, 1800 Mhz and 1900 MHz using the G-NetTrack application on Telkomsel BTS in the University of Nusa Cendana area with Latitude coordinates -10.156738 and Longitude 123.668422 as well as observing frequencies using Spectrum Analyzer to be used as primary data. The next step is to calculate the received power data as secondary data using the Okumura-Hata path loss calculation and COST-231. Based on primary and secondary data an analysis of which propagation model matches the measurements in the field is carried out. From the propagation analysis, it can be concluded that the propagation model that suits the conditions on the campus area is the Okumura-Hatta model.

scholarly journals Compact Rectifier Circuit Design for Harvesting GSM/900 Ambient Energy

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1614
Author(s):  
Surajo Muhammad ◽  
Jun Jiat Tiang ◽  
Sew Kin Wong ◽  
Amjad Iqbal ◽  
Mohammad Alibakhshikenari ◽  
...  
Keyword(s):  
Circuit Design ◽  
Communication Systems ◽  
Path Loss ◽  
Input Power ◽  
Wireless Communication Systems ◽  
Rf Power ◽  
Total Size ◽  
High Input Power ◽  
Wide Range ◽  
Rf Energy

In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. GSM/900 is among the favorable RF Energy Harvesting (RFEH) energy sources that span over a wide range with minimal path loss and high input power. The proposed RFEH rectifier achieves measured and simulated RF-to-dc (RF to direct current) power conversion efficiency (PCE) of 43.6% and 44.3% for 0 dBm input power, respectively. Additionally, the rectifier attained 3.1 V DC output voltage across 2 kΩ load terminal for 14 dBm and is capable of sensing low input power at −20 dBm. The work presents a compact rectifier to harvest RF energy at 900 MHz, making it a good candidate for low powered wireless communication systems as compares to the other state of the art rectifier.

scholarly journals Path-Loss Channel Models for Receiver Spatial Diversity Systems at 2.4 GHz

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Abdulmalik Alwarafy ◽  
Ahmed Iyanda Sulyman ◽  
Abdulhameed Alsanie ◽  
Saleh A. Alshebeili ◽  
Hatim M. Behairy
Keyword(s):  
Communication Systems ◽  
Path Loss ◽  
Spatial Diversity ◽  
Propagation Path ◽  
Real Field ◽  
Channel Models ◽  
Power Combining ◽  
Receiving Antenna ◽  
Diversity Systems ◽  
Loss Models

This article proposes receiver spatial diversity propagation path-loss channel models based on real-field measurement campaigns that were conducted in a line-of-site (LOS) and non-LOS (NLOS) indoor laboratory environment at 2.4 GHz. We apply equal gain power combining (EGC), coherent and noncoherent techniques, on the received signal powers. Our empirical data is used to propose spatial diversity propagation path-loss channel models using the log-distance and the floating intercept path-loss models. The proposed models indicate logarithmic-like reduction in the path-loss values as the number of diversity antennas increases. In the proposed spatial diversity empirical path-loss models, the number of diversity antenna elements is directly accounted for, and it is shown that they can accurately estimate the path-loss for any generalized number of receiving antenna elements for a given measurement setup. In particular, the floating intercept-based diversity path-loss model is vital to the 3GPP and WINNER II standards since they are widely utilized in multi-antenna-based communication systems.

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