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The paper presents a new wireless communication system using Chirp Spread Spectrum (CSS) transmission. The applied modulation scheme is extended with Pulse Position Modulation (PPM) to transmit data for multiple mobile terminals simultaneously. The proposed system is a Low-Power Wide-Area Network (LPWAN) providing very reliable and robust transmission, especially for terminals moving with high speeds...
As the number of units in underwater sensor arrays grow, low-cost localization becomes increasingly important to maintain network scalability. Methods using ambient ocean noise are promising solutions because they do not require external infrastructure, nor expensive on-board sensors. Here we extend past work in stationary array element localization from correlations of ambient noise to a mobile sensor...
For 5G it will be important to leverage the avail- able millimeter wave spectrum. Communication at high carrier frequencies requires antenna arrays at both the base and mobile station. A 1-bit analog to digital converter can effectively reduce the complexity and power consumption of the analog frontend. This is especially interesting in the context of large antenna arrays with a sizable signal bandwidth...
The demands on indoor localization services have grown explosively due to increasing popularity of mobile devices. Though various techniques based on wireless signals have been proposed, the new Bluetooth 4.0 and 4.1 technologies introduce both opportunities and challenges for localization. Like all wireless signals, the fluctuations caused by hardware conditions and environmental dynamics may deteriorate...
This paper presents the results of a dual polarized multiple-input-multiple-output (MIMO) channel measurements, investigating a land mobile satellite (LMS) pedestrian scenario in an urban environment. The channel characterization considers the downlink from a fixed elevated position, emulating a satellite, to a mobile terminal, incorporating line-of-sight (LOS) and non-line-of-sight (NLOS) conditions,...
this paper focuses on the study of electric field spatial variability in the context of mobile telephony base stations exposure. Electric field is computed using a Uniform Theory of Diffraction (UTD) based simulation technique suitable for large urban areas. Two complementary approaches of spatial variability are proposed here. One based upon spatial autocorrelation and the other one on statistical...
Channel randomness can be exploited to generate secret keys. However, to ensure secrecy, it is necessary that the channel response of any eavesdropping party remain sufficiently de-correlated with that of the legitimate users'. In this paper, we investigate whether such de-correlation occurs for a body area network (BAN) operating in an indoor environment at 2.45 GHz. The hypothetical BAN configuration...
Here we present and develop a receiver capable of capturing two RF channels at the same time with a single RF front end and only one IF stage. The idea is to use a low IF digital image rejection receiver that can separate two adjacent RF channels with a negligible cochannel's image interference. We analyze two procedures of compensating, in the IF range, any gain and phase misadjustment generated...
In this paper, a novel 3D localization and identification system based on surface acoustic wave (SAW) devices has been designed and modeled. Two mobile SAW devices have been tracked based on the time of arrival (TOA) approach. The capability of the system to track multiple sensors within the same observation area is demonstrated by configuring the SAW devices in different geometries. Using Barker...
Sustaining good quality of service, in mobile systems, is indeed a direct result of the efficient pre - planning process. Accurate path loss prediction and estimation is one important step toward best deployment of such systems. Recently Terrain roughness parameters are considered essential factors in realizing reliable path loss estimation. In this work, the slope (S) of the route undergone by the...
Recently, there has been a shift from analog to digital wireless communication systems among those used for wireless communication systems. Promotion of the digitization of wireless communication systems has drawn attention to direct-conversion (DC) receivers as means of reducing the cost of digital wireless communication equipment. In this paper, we propose an algorithm for estimating and compensating...
This paper is first in the open literature (to the authors' best knowledge) on wireless channel fading to derive the uplink received signal's fourth-order spatial-correlation coefficient function across a receiving sensor-array's aperture. This derivation is mathematically rigorous and is based on idealized geometric relationships among the mobile transmitter, the base-station's receiving antennas,...
This paper presents the results of indoor and outdoor field trial measurements in order to obtain the probability density functions and the autocorrelation functions of the fading parameters of the κ-μ distribution. The ranges of possible practical values of the κ and μ fading parameters are also obtained from the empirical data. In addition, the instantaneous magnitude variations of κ and μ considering...
Trust plays an important role in protecting the security of mobile ad hoc networks. The node mobility brings challenge to trust propagation, where traditional graph-based propagation methods are difficult to apply. In this paper, we propose a trust establishment and propagation scheme by exploiting natural mobility of mobile ad hoc network nodes. We estimate the moving state of neighboring nodes,...
A novel 2D Mobile-to-Mobile physical model is developed in this paper by considering the underlying physics of free space propagation. When compared to existing statistical channel models, the development and application of our new model is better in terms of complexity as it requires less parameters. In addition, the proposed new model is flexible in applying to any scattering environment whereas...
The absolute phase is the accumulated phase change over an observation interval. It is a new variable for the mobile channel and can be simply derived from the wrapped phase or from the quadrature components. The absolute phase offers extra information about the channel, fostering new techniques for channel characterization and location estimation. However, the absolute phase has not been used in...
In this paper, a new Rayleigh VANET model based on sum-of-sinusoids method (SoS) is presented. Some important statistical properties, such as variance of autocorrelation of the complex envelope and autocorrelation of the squared envelope are derived in detail. Furthermore, for above derived statistical properties, we give an detailed analysis about them by comparing their closeness between simulation...
In the WIMAX (802.16e) standard several small medium access control (MAC) packets may be aggregated to form a MAC burst, forwarded to the physical (PHY) layer The burst transmission is a mechanism to allow multiple MAC protocol data units (PDUs) belonging to the same video channel to be transmitted / received in an aggregated way, in order to enable power saving at the mobile station, by putting the...
DS-CDMA is currently the most widely used multiple-access scheme in mobile communications. It uses spreading sequences to separate different links, e.g., the base-station to user links in the downlink or the user to base-station links in the uplink. These spreading codes are usually allocated when the link is set up and kept fixed for the duration of the transmission. Spreading sequences are designed...
In this paper, we propose a frame synchronization method for underwater acoustic communication on mobile platform. This new method involves transmitting signal based on hyperbolic frequency modulated (HFM) signal as a preamble of the frame, while the receiver uses a correlator which is matched to the transmitted signal. This method can provide us with good signal detection ability which is very important...
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