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Transmission systems using phased array antennas have been proposed, which made it possible to confine the communication area by switching the phase distribution for every symbol. These are known as directional modulation (DM), and the values of the phase shifters are chosen so that the phase of the desired signals on the constellation map is equal to those of the far fields of the phased array antenna...
This paper presents the study of the Doppler shift behavior on a supersonic wireless channel. Firstly, we present the experimental setup of the transmission system and the measurement results obtained. In a second part, we confront the experimental results with those obtained with a wireless ray tracing simulator. This study allows to gain insight in the understanding of the main physical mechanisms...
In this work, Automatic-Repeat-Request (ARQ) and Maximal Ratio Combination (MRC), have been jointly exploited to enhance the confidentiality of wireless services requested by a legitimate user (Bob) against an eavesdropper (Eve). The obtained security performance is analyzed using Packet Error Rate (PER), where the exact PER gap between Bob and Eve is determined. PER is proposed as a new practical...
This paper proposes two metrics for evaluating the low probability of detection (LPD) performance in cooperative wireless communication networks. One metric is the distance ration between the minimum range of all the interceptor-relay/transmitter pairs and the intended transmitter-destination distance. Another is the ratio between the average range of all interceptor-relay/transmitter pairs and the...
In this paper, the principle of a polarization-based measurement system intended for the data recording of the Global Navigation Satellite System (GNSS) signals is described. The measurement arrangement includes left- and right hand circular polarized antennas with separate satellite RF recorders for both polarizations. Based on the recorded data for different antenna polarizations the Line-Of-Sight...
Multi-hop message dissemination in vehicular networks has been largely studied in the past decade. It notably allows to push information to the drivers concerning hazards that they will encounter ahead on the road such as, for instance, traffic jams, ice patches, etc. In this paper, we investigate the performance of several dissemination schemes on a realistic micro-mobility trace: the Madrid Highway...
The limiting impact of interference on the total throughput of large wireless networks has long been recognized by practitioners. The degrees-of-freedom characterization of interference networks has shown that the collapse in scaling without appropriate interference management is a fundamental aspect of these networks, but results from information theory were generally not applicable to network interference...
We propose a coding scheme based on the combination of interleaving with systematic channel codes for secrecy. The basic idea consists of generating a random interleaving key that is used to shuffle/interleave information at the source. The message and the interleaving key are then both encoded with a systematic code and the part related to the interleaving key is removed/punctured before being sent...
A Viterbi algorithm for decoding of the convolutional code is a powerful method for controlling errors in data transmission over a noisy channel. It is based on maximum likelihood algorithm for decoding the data. However, the hardware implementation of Viterbi algorithm become crucial as it consumes large resources due to its complexity. This paper discussed the implementation of ½ rate convolutional...
Results and lessons learned from the implementation of a novel ultra low-latency geo-routing scheme are presented in this paper. The geo-routing scheme is intended for team-based mobile systems whereby a cluster of unmanned autonomous vehicles are deployed to accomplish a critical mission under human supervision. The contention-free nature of the developed scheme lends itself to jointly achieve lower...
The Mobile User Objective System (MUOS) is the next generation UHF satellite communications (SATCOM) system for the Department of Defense (DoD). It consists of four geosynchronous satellites and four ground stations, uses a Spectrally Adaptive Wideband Code Division Multiple Access (SA-WCDMA) waveform, and it will provide worldwide voice and data capabilities for the military. Before it can be used...
Geolocation of wireless emitters using Received Signal Strength Difference (RSSD) and site-specific propagation models offers the advantages of increased accuracy and operation with non-cooperative emitters (where emitted power level or positional information such as GPS from the emitter is unavailable) over more commonplace Received Signal Strength (RSS) systems. An important factor influencing the...
This paper describes measurements conducted in bridge-tunnels to obtain the signal attenuation across 2 tunnels in the bridge as well as the penetration loss of train vehicle at 819.125 MHz. This helped to determine the feasibility for a TETRA base station to communicate with portable receivers from another tunnel in case of base station failure in one tunnel.
While transistor density continues to increase according to Moore's law, Dennard scaling ruling the downsizing of transistor power has broken down due to the increasing rise of leakage occurring in submicron technologies. With every process generation the speed at which transistors can be switched is increasingly exceeding the capacity to dissipate the generated heat, fact that demands highly energy-efficient...
In this article, we carryout performance analysis on energy detectors in myriads of generalized fading environments. We utilize a new “exponential-type” contour and finite-range integral representations for the generalized M-th order Marcum Q-function QM(α,β) when its real order M>0 is not necessarily an integer. The accuracy of the new alternative integral representation for Marcum Q-function...
Spectral efficiency and energy efficiency are fundamental trade-off in wireless communications. Spectral efficiency (SE), defined as the average data rate per unit bandwidth, quantifies how efficiently the available spectrum is utilized. Energy efficiency (EE), defined as the successful transmitted information bits per unit energy from transmitter to receiver, quantifies how efficiently the energy...
Sparse code multiple access (SCMA) which is overloaded by carrying more users than its resource blocks, is different from conventional multiple access method. It can improve spectrum efficiency to solve the problem of large amounts of telecommunication data. Conventional message passing algorithm (MPA) receiver has been used in SCMA, but it has a relatively high complexity. In this paper, we propose...
To understand better what happens when video streaming takes place, this paper introduces a framework to simulate a real-time video streaming over wireless channels. The system is divided into many modules and is simulated with different tools. DUMMYNET is used for the network simulator while FFMPEG is for coder/encoder and sender/receiver module. The video quality is measured by spatial (SSIM and...
The aim of this paper is to trigger a conversation about the assessment, definition of metrics and testing procedures of software-defined GNSS receivers. While the evaluation of traditional (i.e., built on application–specific integrated circuit technology) GNSS receivers is now well–understood, and enjoys both a solid testing industry providing the required equipment and universally agreed figures...
Ionospheric scintillation monitoring is becoming an increasing research activity in order to devise countermeasures to the harmful effects ionospheric activity has on positioning services based on Global Navigation Satellite Systems (GNSS). The amount of amplitude fluctuations in GNSS signals due to scintillation is estimated by the �������� index. For this purpose, traditional closed loop architectures...
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