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In a wireless structural control system, a linear quadratic Gaussian regulator, under measurements loss, is used to limit the RMS structural response to natural hazards. The analysis shows the dependence of the state estimation error, and corresponding control performance, to the packet error probability and transmission delay. These metrics are studied for two communication access techniques: code-division...
Underwater acoustic communications can be used for several applications. When the underwater link is related to a reservoir, applications can go from water monitoring, both in terms of pollution and physical characteristics, as for example, temperature. Another class of applications can be the remote control of small vehicles/vessels. Due to the limited depth, this kind of underwater acoustic connection...
In wireless sensor networks, multi-node cooperative relaying (MR) scheme represents a potential candidate to combat the effects of channel fading by exploiting diversity gain achieved via cooperation among the relays nodes. But, a great many of relaying channels are employed in MR system, which means that the number of required channels, the energy consumption and transmission delay all increase linearly...
The design of wireless embedded systems needs their efficient and realistic simulation to verify that requirements are met. The reproduction of communication behavior is crucial to assess the performance of hardware and software components, e.g., dependability and energy consumption. This work presents and discusses different levels of abstraction for the simulation of the communication behavior....
The behavior of Networked Embedded Systems (NES) is not only driven by network components but also by the surrounding environment. To verify the correct behavior of such systems, different tests should be performed under different environmental conditions. The complexity and expense of testing such systems in real environments leads us to propose a simulation-based approach to tackle this problem...
A relay diversity scheme is proposed to provide diversity gain and better system performance in wireless fading environment. The hybrid relay diversity (HRD) scheme combines the concept of distributed space-time block coding (DSTBC) and relay cyclic delay diversity (RCDD) for OFDM-based relay communication network with more than one relay nodes. The scheme addresses the issue of achieving maximum...
Time-reversed orthogonal frequency division multiplexing (TR-OFDM) has recently received attention as a promising scheme for supporting single-input multiple-output (SIMO) communications over time-dispersive fading channels. In TR-OFDM, the time reversal processing cleverly converts multiple time-dispersive fading channels associated with SIMO-OFDM into a single channel with generally smaller time...
Mobile ad hoc networks (MANETs) are notoriously difficult to defend against attack. In this paper we demonstrate that by optimizing a previously reported covert timing channel, it is possible to simultaneously improve the reliability of the channel and create a metric that reliably detects attacks. Using standard methods from information theory, we compute the capacity of the covert channel and show...
Recently, it has been studied how to reduce the probability of interception and to increase the efficient security in the wireless digital communication systems. Among the possible approaches for the information security, the chaotic signal can be used to encode information very efficiently in many ways due to the inherent characteristic of irregularity. In this paper, in noise and interference environment,...
In this paper the bit error rate (BER) performance of a tunable impedance matching network (TMN) is shown using a QAM digital modulation scheme over an AWGN channel. The characterized TMN is based on Barium-Strontium-Titanate (BST) ferroelectric thick-film varactors with a maximum DC tuning voltage of 90V. Inherent dispersive behavior is subsumed in the forward transmission of the passive components...
Low density parity check (LDPC) codes are used in various communication standards. However, LDPC decoders are complex and power hungry. In this paper, we present an energy-efficient LDPC decoder based on statistical error compensation (SEC). Three different size LDPC codes, (50,25), (800,400), and (1800,900) were implemented with 5 iterations/block. Circuit simulations in a commercial 45nm process...
In this paper bit error rate (BER) performances of the built-in MATLAB multipath fading simulator, which recreates a theoretical channel based on user's specified parameters, have been compared to that of a ‘playback’ based channel simulator. The MATLAB fading simulator has been configured with parameters estimated from the same radio channel measurements used by the ‘playback’ based simulator. The...
In recent years, the performance analysis of UWB (Ultra-Wide Band) systems has been an area of considerable interest. To understand the fading in UWB caused by the multipath propagation in complicated environment of underground mines, a precise model of the channel response is expected for designing a UWB system. This paper presents the comparison between the UWB channel proposed by study group IEEE...
TH (Tomlinson-Harashima) precoding is an important nonlinear precoding method. In this paper, the bit error rate (BER) performance for the TH precoding system is investigated over time varying and dispersive Ricean fading channels. Assuming that there exists a certain delay introduced by the feedback channel, we first model the feedback error of channel station information (CSI) due to the feedback...
Non-coherent energy detection (ED) IR-UWB receivers exhibit strong advantages in low data rate, low power and low cost applications such as RFID and Wireless Sensor Networks. However, the performance of ED receivers is usually suffered from the noise enhancement due to the large time-bandwidth product. The integration region of the receiver integrator significantly affects the bit error rate (BER)...
The paper proposes a multi-hop Reed-Solomon (RS) encoding scheme for image transmission on wireless sensor networks. In this scheme, an encoding task is divided into several small processing components, which are then distributed to multiple nodes along a path from a source node to a cluster head within a cluster. We perform extensive computational simulations to validate our method using RS codes...
This paper addresses the issue of packet scheduling with spatial division multiplexing (SDM) techniques of multiple input multiple output (MIMO) antenna in the 3GPP Long Term Evolution (LTE) downlink. Considering the restricted condition of selecting SDM techniques, a novel packet scheduling algorithm with quality of service (QoS) support in LTE downlink MIMO system, named QoS-DMO, is proposed. QoS-DMO...
In this paper, we analyze the channel estimation technique for OFDM (orthogonal frequency division multiplexing) used in VLC (Visible Light Communication system). A Post-Processing DFT (Discrete Fourier Transformation) channel estimation method was proposed to improve the system performance by eliminating the noise outside the maximum channel delay. After linear interpolation, the channel estimation...
In Orthogonal Frequency Division Multiplexing and Discrete Multitone transceivers, a guard interval called Cyclic Prefix (CP) is inserted to avoid inter-symbol interference. The length of the CP is usually greater than the impulse response of the channel resulting in a loss of useful data carriers. In order to avoid long CP, a time domain equalizer is used to shorten the channel. In this paper, we...
It has been shown that due to its smaller signal bandwidth (96 KHz), DRM+ signal could suffer from flat fading degradation at low receiver speeds, particularly in urban environments. To alleviate this problem, a simple transmit delay diversity (TDD) has been proposed in the standard. This paper tries to investigate this issue by presenting the performance results of multipath fading characterizations...
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