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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...
Direct signal and surface clutter cancellation is an important problem in bistatic noise radar. LMS filter is employed to suppress the direct signal and clutter in this work. Direct signal and clutter cancellation ratio (DCR) is used to evaluate the performance of suppression. The impact of two factors, SNR of reference signal and fractional delay of clutter, is analyzed. The analysis is verified...
We present an analytical model for a random resource allocation and scheduling scheme for non-real-time polling service (nrtPS) traffic in IEEE 802.16e network. We adopt two system assumptions; unsaturation condition for the queue of each mobile station, and random amount of resources in a frame for each nrt-PS traffic, which are realistic for practical network systems. By jointly considering the...
We analyze the spectral zero-crossing rate (SZCR) properties of transient signals and show that SZCR contains accurate localization information about the transient. For a train of pulses containing transient events, the SZCR computed on a sliding window basis is useful in locating the impulse locations accurately. We present the properties of SZCR on standard stylized signal models and then show how...
This paper proposes an audio-data hiding scheme for amplitude-modulation (AM) radio broadcasting systems. The digital-audio method of watermarking based on cochlear delay (CD) that we previously proposed is employed in this scheme to send an inaudible message. We investigate the feasibility of a data-hiding scheme in the AM domain by applying the method of CD-based inaudible watermarking. The proposed...
In this paper, we propose a mobile optical wireless (OW) system that employs a beam delay and a power adaptation multibeam clustering method in conjunction with an angle diversity receiver (BDPA-BCM). Our ultimate goal is to improve the signal to noise ratio (SNR), reduce the delay spread and increase the received optical power under multipath dispersion, background noise and mobility. A significant...
In this paper, we introduce a novel fast angle and power adaptation method in optical wireless (OW) systems. The fast angle and power adaptive line strip multibeam system (FAPA-LSMS) can identify the optimum spots distribution based on a divide and conquer (D&C) algorithm and can achieve a signal-to-noise ratio (SNR) performance comparable to that obtained using the normal APA-LSMS. This results...
This paper proposed a coding mode selection method for video transmission over wireless networks. Unlike previous mode selection methods disregarding channel distortion or assuming constant packet loss rate (PLR), this method includes a cross-layer controller to collect both source and channel information. The mode selection process is formulated as a delay constrained distortion minimization problem...
Being reliable and real-time, are the two most challenging requirements of wireless industrial networks due to the shared, error-prone and non-deterministic behaviour of wireless communication medium. Retry-Limit (RL) parameter of IEEE 802.11 standard directly effects on the packet reliability, whereas other parameters mostly effect on packet delay. In this paper, at first the delay-reliability trade-off...
The delay constraints imposed by future wireless applications require a suitable metric for assessing their impact on the overall system performance. Since the classical Shannon's ergodic capacity fails to do so, the so-called effective rate was recently established as a rigorous alternative. Yet, most prior relevant works have considered only the typical case of Rayleigh fading which allows for tractable...
This paper presents two fast and computationally efficient interferometric algorithms that allow high accuracy, unambiguous angle-of-arrival (AOA) estimates to be obtained using physically large wideband antennas that are suitable for electronic surveillance. The performance of the algorithms are compared against conventional interferometric techniques using simulations and are also verified experimentally.
The concept of the effective service capacity is an analytical framework for evaluating QoS-constrained queuing performance of communication systems. Recently, it has been applied to the analysis of different wireless systems like point-to-point systems or multi-user systems. In contrast to previous work, we consider in this work slot-based systems where a scheduler determines a packet size to be...
We address the problem of passive estimation of the Time-Difference of Arrival (TDOA) of an unknown, stochastic signal, at two sensors. The key question addressed here is whether additional sensors, receiving the same signal at various relative delays, can serve to improve the accuracy in estimating the TDOA of interest between the first two sensors (without exploiting any underlying parameterization,...
In order to achieve higher data rates and more reliable QoS, coordinated multipoint transmission/ reception (CoMP) is raised in 3GPP release 10 and beyond. Cooperative transmission can effectively improve the performance of cell-edge users with the cost of exchange load between service eNodeB and cooperative eNodeB. Previous work of 3GPP release 11 has noticed the modeling of cooperative backhaul...
Inclusion of multipath ghost target images, alongside direct target images, is shown to improve performance in radar target classification. When ultra wideband waveforms are employed there is sufficient range resolution that the components of the received signal relating to indirect paths appear as unique peaks. The additional returns result in a point spread function with peaks at locations other...
In this paper, a minimum nonlinear prediction error (MNPE) based channel equalization and timing recovery technique is proposed for chaotic communications systems. This blind technique utilizes the short-term predictability of a chaotic signal to estimate the equalizer coefficients and the timing delay without any training signals. Both computer simulation and experimental setup are carried out to...
In this paper, a ternary stimulus is proposed for testing SD Analog-to-Digital Converters (ADCs). The ternary stimulus is composed of three logic levels {-1,0,1} and is obtained by adding a binary stream with a delayed version of itself. Only four switches are added to the input stage of the modulator of the ADC for facilitating the injection of the ternary stimulus. Compared...
An accurate channel estimation is crucial for the novel time domain synchronous orthogonal frequency-division multiplexing (TDS-OFDM) scheme in which pseudo noise (PN) sequences serve as both guard intervals (GI) for OFDM data symbols and training sequences for synchronization/channel estimation. This paper studies the channel estimation method based on the cross-correlation of PN sequences. A theoretical...
Incremental opportunistic relaying (IOR) has been proposed to increase the spectral efficiency of the two-phase cooperative transmissions by exploiting limited feedback from the destination node. Specifically, the relaying process is activated only if the source-destination channel is of insufficient quality. In this case, the feedback instructs the best relay to forward the source message to the...
Coordinated Multi-Point (CoMP) transmission schemes can provide large spectral efficiency gains in cellular networks. Because of the coordination among neighbor basestations, the planning interval for resource allocation with CoMP is longer than for uncoordinated local transmission modes. Especially for bursty data traffic, this planning interval might be too long to keep up with changes in offered...
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