المصدر: IEEE Transactions on Vehicular Technology. Apr2022, Vol. 71 Issue 4, p4428-4437. 10p.

مصطلحات موضوعية: *WIRELESS Internet, RADIO wave propagation

مستخلص: The fine timing measurement (FTM) protocol is designed to determine precise ranging between Wi-Fi devices using round-trip time (RTT) measurements. However, the multipath propagation of radio waves generates inaccurate timing information, degrading the ranging performance. In this study, we use a neural network (NN) to adaptively learn the unique measurement patterns observed at different indoor environments and produce enhanced ranging outputs from raw FTM measurements. Moreover, the NN is trained based on an unsupervised learning framework, using the naturally accumulated sensor data acquired from users accessing location services. Therefore, the effort involved in collecting training data is significantly minimized. The experimental results verified that the collection of unlabeled data for a short duration is sufficient to learn the pattern in raw FTM measurements and produce improved ranging results. The proposed method reduced the errors in raw distance measurements and well-calibrated ranging results requiring the collection of ground truth data by 47–50% and 17–29%, respectively. Consequently, positioning errors were reduced by 17–30% compared to the well-calibrated ranging scenario. [ABSTRACT FROM AUTHOR]

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المؤلفون: Ai, Yun¹ yun.ai@ntnu.no, deFigueiredo, Felipe A. P.² felipe.figueiredo@inatel.br, Kong, Long³ long.kong@uni.lu, Cheffena, Michael¹ michael.cheffena@ntnu.no, Chatzinotas, Symeon³ schatzin@ieee.org, Ottersten, Bjorn³ bjorn.ottersten@uni.lu

المصدر: IEEE Transactions on Vehicular Technology. Jul2021, Vol. 70 Issue 7, p7272-7276. 5p.

مصطلحات موضوعية: RADIO wave propagation, PHYSICAL layer security, VEHICULAR ad hoc networks, SIGNAL-to-noise ratio, INTELLIGENT transportation systems, RADIO frequency

مستخلص: Reconfigurable intelligent surfaces (RIS) is considered as a revolutionary technique to improve the wireless system performance by reconfiguring the radio wave propagation environment artificially. Motivated by the potential of RIS in vehicular networks, we analyze the secrecy outage performance of RIS-aided vehicular communications in this paper. More specifically, two vehicular communication scenarios are considered, i.e., a vehicular-to-vehicular (V2V) communication where the RIS acts as a relay and a vehicular-to-infrastructure (V2I) scenario where the RIS functions as the receiver. In both scenarios, a passive eavesdropper is present attempting to retrieve the transmitted information. Closed-form expressions for the secrecy outage probability (SOP) are derived and verified. The results demonstrate the potential of improving secrecy with the aid of RIS under both V2V and V2I communications. [ABSTRACT FROM AUTHOR]

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المؤلفون: Solomitckii, Dmitrii¹ (AUTHOR) dmitrii.solomitckii@tuni.fi, Koucheryavy, Yevgeni¹ (AUTHOR) evgeny.kucheryavy@tuni.fi, Semkin, Vasilii² (AUTHOR) vasilii.semkin@uclouvain.be, Karttunen, Aki³ (AUTHOR) aki.karttunen@alumni.aalto.fi, Petrov, Vitaly¹ (AUTHOR) vitaly.petrov@tuni.fi, Nguyen, Sinh Le Hong⁴ (AUTHOR) sinh.l.nguyen@ericsson.com, Nikopour, Hosein⁵ (AUTHOR) hosein.nikopour@intel.com, Haneda, Katsuyuki³ (AUTHOR) katsuyuki.haneda@aalto.fi, Andreev, Sergey¹ (AUTHOR) sergey.andreev@tuni.fi, Talwar, Shilpa⁵ (AUTHOR) shilpa.talwar@intel.com

المصدر: IEEE Transactions on Vehicular Technology. Feb2020, Vol. 69 Issue 2, p1227-1236. 10p.

مصطلحات موضوعية: RADIO wave propagation, CANYONS

مستخلص: The communications between two driving vehicles along a narrow street may be limited by the presence of a third vehicle blocking the transmission. In this work, we investigate radio wave propagation at 28 GHz in an urban street canyon scenario by conducting channel measurements, where the vehicle(s) occlude(s) the line-of-sight path. We quantify the impact of the car blockage and study the alternative propagation paths, which can be used for establishing a data link. Based on the obtained results, we report that besides the low-loss (3.4 dB) reflection from the wall, a radio link through the blocking car may potentially be established for data sharing. Specifically, the attenuation through clear windows is 2 dB, while the attenuation caused by sun protective film is 15 dB. Diffraction over the car and propagation in foliage reduce the multipath power drastically by 21–24 dB and 16–19 dB, respectively, and cannot be associated with reliable links. Finally, measurement results were compared with the ray-based simulation data, which demonstrate agreement to within ± 4.3 dB of measured losses. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Ali, G. G. Md. Nawaz, Noor-A-Rahim, Md., Chong, Peter Han Joo, Guan, Yong Liang

المصدر: IEEE Transactions on Vehicular Technology. Aug2018, Vol. 67 Issue 8, p6774-6787. 14p.

مصطلحات موضوعية: VEHICULAR ad hoc networks, RADIO wave propagation, LINEAR network coding, COMPUTER network reliability, INTELLIGENT transportation systems

مستخلص: In this paper, we study the impact of obstacles (such as buildings) in the radio propagation in the urban vehicular network's environment. The impact has been realized not only by the network-level performance metrics, but also by the application-level performance metrics. A majority of the existing works consider perfect physical layer, which ignores the impact of path loss and shadowing effect in radio propagation caused by the urban canyon. First, we show that ignoring the impact of obstacles in radio propagation provides very high superficial network-level performance. Second, under obstacle shadowing, we perform analytical analysis and Ns-3 based realistic urban vehicular simulation of current dedicated short-range communication based safety message broadcasting to study the achievable performance of application-level performance metrics. This study reveals the answer of the key question, whether the achieved network-level performance metric is good enough for the safety-critical applications under the acute attenuation in radio propagation in urban environment. Third, we propose opportunistic vehicle-assisted or dedicated road side unit-assisted network coded relaying for improving reliability at road intersection. Simulation results show that the proposed approach improves more than 65% reliability for delay sensitive and around 25% reliability for less delay sensitive applications at intersections. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Huang, Rui¹, Wu, Jing¹, Long, Chengnian¹, Zhu, Yanmin², Li, Bo³, Lin, Yi-Bing⁴

المصدر: IEEE Transactions on Vehicular Technology. Dec2017, Vol. 66 Issue 12, p11306-11316. 11p.

مصطلحات موضوعية: *INTERNET protocols, *WIRELESS communications, RADIO wave propagation, VEHICULAR ad hoc networks, MULTICHANNEL communication

مستخلص: Information dissemination in VANETs mainly focuses on, e.g., the propagation of cooperative awareness messages and decentralized environmental notification messages on the control channel. As vehicles advance toward higher automation levels, VANETs should support more complex traffic services, which generates the demand for the propagation of Internet Protocol (IP)-based information and service data in multichannel environment as specified by IEEE Standard for Wireless Access in Vehicular Environments (WAVE). Multisource propagation in the multichannel environments will incur multisource relay confliction (MRC) which leads to higher latency and lower information propagation speed (IPS). However, the problem of how to mitigate the impact of MRC and maintain high IPS has not been studied sufficiently. In this paper, we propose success probability based relay contention algorithm (SPRCA) for mitigating the impact of MRC under WAVE channel environments. SPRCA presents a vital metric, success probability, for each vehicle to determine whether to join the relay candidate set of certain source and execute relay contention algorithm. SPRCA explores both real time location information of vehicles and stochastic properties of vehicular distribution. We construct a theoretical model for analyzing the performance of SPRCA with a stochastic geometry-based approach and derive the properties of the performance of SPRCA. We further demonstrate the network performance and the practicality in dynamic VANETs of SPRCA through simulations with realistic traffic flow data. [ABSTRACT FROM AUTHOR]

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المؤلفون: Gapeyenko, Margarita¹, Samuylov, Andrey¹, Gerasimenko, Mikhail¹, Moltchanov, Dmitri¹, Singh, Sarabjot², Akdeniz, Mustafa Riza², Aryafar, Ehsan³, Himayat, Nageen², Andreev, Sergey¹, Koucheryavy, Yevgeni¹

المصدر: IEEE Transactions on Vehicular Technology. Nov2017, Vol. 66 Issue 11, p10124-10138. 15p.

مصطلحات موضوعية: MILLIMETER wave propagation, MICROWAVE communication systems, MILLIMETER wave communication systems, CELL phone security measures, WIRELESS channels

مستخلص: Millimeter-wave (mmWave) propagation is known to be severely affected by the blockage of the line-of-sight (LoS) path. In contrast to microwave systems, at shorter mmWave wavelengths such blockage can be caused by human bodies, where their mobility within environment makes wireless channel alternate between the blocked and non-blocked LoS states. Following the recent 3GPP requirements on modeling the dynamic blockage as well as the temporal consistency of the channel at mmWave frequencies, in this paper, a new model for predicting the state of a user in the presence of mobile blockers for representative 3GPP scenarios is developed: Urban micro cell street canyon and park/stadium/square. It is demonstrated that the blockage effects produce an alternating renewal process with exponentially distributed non-blocked intervals, and blocked durations that follow the general distribution. The following metrics are derived 1) the mean and the fraction of time spent in blocked/non-blocked state, 2) the residual blocked/non-blocked time, and 3) the time-dependent conditional probability of having blockage/no blockage at time t1 given that there was blockage/no blockage at time t0 . The latter is a function of the arrival rate (intensity), width, and height of moving blockers, distance to the mmWave access point (AP), as well as the heights of the AP and the user device. The proposed model can be used for system-level characterization of mmWave cellular communication systems. For example, the optimal height and the maximum coverage radius of the mmWave APs are derived, while satisfying the required mean data rate constraint. The system-level simulations corroborate that the use of the proposed method considerably reduces the modeling complexity. [ABSTRACT FROM PUBLISHER]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Jafari, Amir H.¹, Venkateswaran, Vijay², Lopez-Perez, David³, Zhang, Jie⁴

المصدر: IEEE Transactions on Vehicular Technology. Jul2017, Vol. 66 Issue 7, p5866-5878. 13p.

مصطلحات موضوعية: *BANDWIDTHS, *WIRELESS communications, *TELECOMMUNICATION systems, RADIO wave propagation, SIGNAL processing

مستخلص: In ultra-dense small cell networks, spatial multiplexing gain is a challenge because of the different propagation conditions. The channels associated with different transmit–receive pairs can be highly correlated due to the: 1) high probability of line-of-sight (LOS) communication between user equipment (UE) and base station (BS) and 2) insufficient spacing between antenna elements at both UE and BS. In this paper, we propose a novel transmission technique titled Diversity Pulse Shaped Transmission (DPST), to enhance the throughput over the correlated multiple-input multiple-output (MIMO) channels in an ultra-dense small cell network. The fundamental of DPST is to shape transmit signals at adjacent antennas with distinct interpolating filters, introducing pulse shaping diversity. In DPST, each antenna transmits its own data stream with a relative deterministic time offset—which must be a fraction of the symbol period—with respect to the adjacent antenna. The delay is interpolated with the pulse shaped signal generating a virtual MIMO channel that benefits from increased diversity from the receiver perspective. To extract the diversity, the receiver must operate in an oversampled domain, and hence, a fractionally spaced equalizer (FSE) is proposed. The joint impact of DPST and FSE helps the receiver to sense a less correlated channel, eventually enhancing the UE's throughput. Moreover, in order to minimize the spatial correlation, we aim to optimize the deterministic fractional delay. Simulation results show that applying DPST to a correlated channel can approximately enhance the UE throughput by 1.93\times and 3.76\times in \text2\,\times\, \text2 and \text4\,\times \,\text4 MIMO systems, respectively. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Kamoda, Hirokazu¹, Kitazawa, Shoichi², Kukutsu, Naoya³, Kobayashi, Kiyoshi⁴, Kumagai, Tomoaki²

المصدر: IEEE Transactions on Vehicular Technology. Sep2016, Vol. 65 Issue 9, p6831-6841. 11p.

مصطلحات موضوعية: *STANDARD deviations, COMPUTER control systems of automobile engines, RADIO wave propagation, WAVELENGTHS, WIRELESS sensor networks

مستخلص: With the aim of providing an overview of the propagation channels in a vehicle engine compartment, narrow-band (1–2 MHz) and broadband (500 MHz) channels in the frequency range from 2 GHz to 7.75 GHz were analyzed. To secure as much generality of analysis as possible, more than 500 propagation channels of seven types of automobiles were measured. The path loss and delay spread were analyzed in terms of distance and frequency. Models that take into account the interdependence of distance and frequency were used, considering that the object sizes in an engine compartment are comparable to the measurement wavelengths. The path-loss exponent for distance was about one below a break point of 450 mm and about three above the break point. The exponent for frequency was around one. The root-mean-square (RMS) delay spread increased as distance increased. Based on the obtained delay spread model, the propagation channel model was finally provided, which is a function of frequency and distance. Then, the channel model was validated by comparing delay spreads calculated from the generated channels and the measured channels. It is also noted that the channel dependence on the types of vehicle was not significant. [ABSTRACT FROM PUBLISHER]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Tegos, Sotiris A., Tyrovolas, Dimitrios, Diamantoulakis, Panagiotis D., Liaskos, Christos K., Karagiannidis, George K.

المصدر: IEEE Transactions on Vehicular Technology; Jul2022, Vol. 71 Issue 7, p7297-7307, 11p

مصطلحات موضوعية: PROBABILITY density function, CUMULATIVE distribution function, CHARACTERISTIC functions, RADIO wave propagation, DISTRIBUTION (Probability theory), RAYLEIGH model, SYMBOL error rate

مستخلص: Meta-surfaces intend to improve the performance of future wireless networks significantly by controlling the wireless propagation and shaping the radio waves according to the generalized Snell's law. A recent application of meta-surfaces are reconfigurable intelligent surfaces that are mainly proposed for the reflection and steering of the impinging signal. In this article, we introduce randomly reconfigurable surfaces (RRSs) aiming to diffuse the incoming wave and characterize the performance of an RRS-assisted communication network. To facilitate the performance analysis of an RRS-assisted network, first, we present novel closed-form expressions for the probability density function, the cumulative distribution function, the moments, and the characteristic function of the amplitude of the distribution of the sum of double-Nakagami- $m$ random vectors, whose amplitudes follow the double-Nakagami- $m$ distribution, and phases following the circular uniform distribution. We also consider a special case of this distribution, namely the distribution of the sum of Rayleigh-Nakagami-m random vectors. Then, we exploit the obtained expressions to investigate the RRS-assisted composite channel, assuming that the two links undergo Nakagami- $m$ fading. Specifically, closed-form expressions for the outage probability, the average received signal-to-noise ratio, the ergodic capacity, the bit error probability, the amount of fading, and the channel quality estimation index are provided to evaluate the performance of the considered system. Finally, these metrics are also derived for the practical special case where one of the two links undergoes Rayleigh fading, implying that this link is non-line-of-sight. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Ambroziak, Slawomir J.¹, Katulski, Ryszard J.¹

المصدر: IEEE Transactions on Vehicular Technology. Nov2013, Vol. 62 Issue 9, p4276-4287. 12p.

مصطلحات موضوعية: *CELL phones, RADIO wave propagation, CONTAINER terminals, ELECTROMAGNETIC wave propagation, THEORY of wave motion

مستخلص: In this paper, a novel empirical propagation model for mobile radio links in a container terminal environment is presented. Measurement propagation research carried out in the Deepwater Container Terminal (DCT) in Gdańsk, Poland is described, and the investigated environment is characterized. The results of the statistical evaluation of the new model are discussed. In addition, statistical tuning of the Walfisch–Ikegami model for the investigated environment is presented. [ABSTRACT FROM PUBLISHER]

: Copyright of IEEE Transactions on Vehicular Technology is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)