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Quantification of the multipath-induced error in GNSS code-based range measurements is usually entrusted to curves as the multipath error envelope (MEE). Although very useful for comparative evaluations, these metrics do not include any realistic information on the propagation channel statistical characterization and consequently cannot be used to quantify the multipath error in an absolute way. A...
This paper proposes a cross-layer control mechanism to stream efficiently scalable videos to mobile receivers. Its goal is to maximize the quality of the received video while accounting for the variations of the characteristics of the transmitted content and of the channel. The control problem is cast in the framework of Markov Decision Processes. The optimal actions to apply to the system are learned...
An alternative implementation of the filter bank multicarrier (FBMC) concept is introduced. It is based on an FFT whose size is the length of the prototype filter. The approach clarifies the connection with OFDM and its main benefit is in the receiver, where high performance sub-channel equalization and timing offset compensation are achieved in a straightforward manner without additional delay. The...
The Pre-FFT minimum mean square error (MMSE) antenna array (AA) can depress the large delay paths signal in multi-path fading channel by performing the spatial filtering to desired/undesired signals in time domain. For mobile OFDM application, the conventional AA scheme cannot render the system less sensitive to Doppler effects. In this paper, an AA scheme is derived to suppress both Doppler shift...
In smart metering systems, when the density of node is high or distance of communication range is large, the adjacent node number becomes large. If routing based on the number of hop from the sink node is used in such a network, the deviation of load will become large and it will shorten the network lifetime, also degrades other network performance. In this paper, we proposed the techniques solving...
In-band spectrum sensing requires that the secondary users (SU) periodically suspend their communication in order to determine whether the primary user (PU) has started to utilize the channel or not. In contrast, in spectrum monitoring the SU can detect the emergence of the PU from its own receiver statistics such as receiver error count (REC). Previously it is shown that in AWGN channels, a hybrid...
Conventional frequency-domain receivers require a fixed channel within the block duration being the performance severely affected in presence of strong Doppler effects. In this paper we propose an iterative receiver for SC-FDE schemes (Single Carrier with Frequency-Domain Equalization) that is able to mitigate strong Doppler effects. This receiver can be regarded as a modified turbo equalizer, implemented...
Providing integrated network functionality in VHF tactical networks has been problematic for many years. Modern MANET routing techniques can swamp the limited bandwidth of ground-based tactical networks while legacy techniques are inefficient. In this paper, we expand on our previous work using a cross-layered approach and propose a new technique for Multicast Enhanced Opportunistic Routing (MEOR)...
In this paper, we introduce a novel multipath mitigation technique for binary offset carrier signals in global navigation satellite system (GNSS). The proposed technique is based on nonlinear operator called Teager - Kaiser Operator, which initially has been used to obtain energy of physical process. Moreover, the proposed multipath mitigation technique tries to reduce or remove the error caused by...
In this paper, multipath error on Global Navigation Satellite System (GNSS) signals in urban environments is characterized with the help of Light Detection and Ranging (LiDAR) measurements. For this purpose, LiDAR equipment and Global Positioning System (GPS) receiver were used to collect data in an urban environment. LiDAR measurements are used to extract environment features. GPS raw measurements...
The paper describes an optimized solution for the a Galileo Pseudolite based on a Transceiver consisting in the integration of a very accurate dual carrier (programmable E1-E6 or E1-E5) GALILEO Signal In Space Generator and a matched dual carrier GALILEO precision Time Receiver in a very compact (16 mm by 10 mm) state of art Software Radio Hardware platform. This solution simplifies the synchronization...
In-band spectrum sensing protocols require that the secondary users (SU's) periodically suspend their transmission periods and sense the channel in order to determine whether the primary user (PU) has emerged or not. There is a tradeoff between the spectrum sensing period and the throughput of the SU, often referred to as sensing-throughput tradeoff. In this paper, using the receiver error count,...
Scale Time Offset Robust Modulation (STORM) is a waveform design technique involving the simultaneous transmission of a base waveform as well as a time-scaled and time-delayed copy of that waveform. For some applications this technique is attractive as a possible candidate to enhance synchronization performance, due to the different tradeoffs of its performance properties. This paper first presents...
In this paper, we use a realistic energy consumption model for wireless networks to analyze the energy and bandwidth performance of wireless networks with transmit power control. Transmit power affects the performance at the physical layer. When the transmit power increases, the capacity at the physical layer increases accordingly, which reduces the energy consumption and increases throughput. Transmit...
The problem of inferring side information regarding an underwater acoustic (UWA) channel from the environmental signature imprinted on waveforms by the propagation medium, particularly the transmitter/receiver configuration and relative speed vector, is addressed in this paper. The main contribution of this work is to develop techniques to automatically deal with wavefront classification, i.e., to...
Delay tomography is one of the key components of network tomography that has been studied for a number of years. In this paper, an EM-like algorithm is proposed for the delay tomography of the tree topology that uses a dynamic-programming strategy to perform n-fold deconvolution. The effectiveness of the algorithm has been confirmed by simulation.
This article deals with the radiation of sound from ultrasonic transducers located on a flat surface and bounding a shear flow. The aim of the experiments is to measure time delays between flushed transducers in order to characterize flow velocity. Considering that the sound has an infinitely small wavelength, comparison between numerical (simulated using Matlab) and experimental results shows that...
Satellite based coherent beacon systems have been used for ionospheric studies by measurement of the differential phase between the carriers. A simulation study of such a system is presented in this paper, along with the differences in performance occurring by using a spread spectrum beacon over this conventional one.Usage of spread spectrum has the desirable properties of exhibiting a narrowband...
We show that the performance of downloads in a 3G/HSPA mobile network can be significantly degraded by a concurrent upload that saturates the uplink buffer on the mobile device. In particular, we found in some instances that download speeds can be reduced by over an order of magnitude from 2,000 kbps to 100 kbps. To mitigate this problem, we propose a new algorithm called Receiver-side Flow Control...
Group communication plays an important role in the distribution of real-time data for IPTV, multimedia conferencing, or online multiplayer games, but IP multicast remains unsupported in today's global Internet. Hybrid solutions that bridge between overlay and underlay multicast are a promising escape from the deployment dilemma of multicast. In this paper, we examine the real-time capabilities of...
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