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In this paper, new exact and approximate moment generating functions (MGF) expression for generalized fading models are derived. Specifically, we consider the η-λ-μ, α-μ, α-η-μ, α-λ-μ, α-κ-μ, and α-λ-η-μ generalized fading distributions to derive approximate MGF expressions. The new expressions are very accurate and, in contrast to earlier results in the literature, avoid any complicated special functions,...
The performance of six different shapes of pulses is compared for Packet Collision (PC) and Standard Gaussian Approximation (SGA) communication systems, based on the requirements of the Federal Communications Commission (FCC) emission mask. The shapes are a second derivative sinusoid Gaussian pulse, a second order Gaussian pulse and the first four orders of modified Hermite pulses. For the SGA model,...
Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation technique. It supports high data rates over wireless radio channels. Due to high peak-to-average power ratio, OFDM is sensitive to the non-linear effects of the power amplifier. So, many methods of PAPR reduction techniques have been proposed. Of these, the distortionless method of PAPR reduction is Partial Transmit Sequence...
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....
Low-power and Lossy Networks (LLNs), like wireless networks based upon the IEEE 802.15.4 standard, have strong energy constraints, and are moreover subject to frequent transmission errors, not only due to congestion but also to collisions and to radio channel conditions. This paper introduces an analytical model to compute the total energy consumption in an LLN due to the TCP protocol. The model allows...
The design, manufacture and deployment of embedded systems become increasingly complex and multidisciplinary process. Before the steps of manufacturing and deployment, a simulation and validation phase is necessary. Given the increasing complexity of systems such as telecommunications systems, control systems and others, a specific simulation and validation process must take place. This simulation...
As many experimental simulations were conducted in the field of wireless sensor networks, OMNeT++ has gained popularity due its scalability and rich graphical user interface. The use of OMNeTT++ based simulation for reliable point-to-point wireless transmission and realistic Segmentation and Reassembly (SAR) with error control for a distributed wireless sensor network are explored. Simulations demonstrated...
In this paper, an iterative multiple-symbol differential detection (MSDD) scheme for differential LDPC codes is considered over slow and fast Rayleigh fading channels. The metric computation algorithm and its simplified algorithm used to output soft information for MSDD are derived. Simulation results demonstrate that the bit error rate (BER) performance of the proposed system is close to that of...
Contrast to the adaptive equalization method, which need a training period, blind equalization technique, which only the output signal is known, is needed in many communication systems, such as multipoint data network or wireless communication systems. In this paper, a new blind equalization approach, called expectation maximization blind equalization (EM-BE), is proposed. First, transform the convolution...
In this paper, a new method to model and simulate a wireless communication system based on system on chip design methodology will be presented. The network performance effected by the amount of detail in the simulation model. Hence there is a need to develop suitable abstractions that maintain the accuracy of the simulation while keeping the computational resource requirements low. The integration...
By exploiting properties of the wireless medium, network coding may provide even larger throughput increases for wireless networks than possible for wired networks. In particular, simultaneously transmitted signals are seen as noisy linear combinations at the antennas of receivers. It is thus quite tempting to use the physical layer to directly perform network coding "on the air". However,...
In this paper, we propose a novel error concealment algorithm for intra frames of h.264/AVC. By using the high correlation of adjacent frames sequence, the proposed algorithm performs quadratic interpolation to the error pixel value of the concealed intra frame from the corresponding pixels of the previously decoded frame and the adjacent blocks received correctly while remaining the least distortion...
In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated...
Three applications in wireless networks where model-free stochastic learning is applicable, are discussed. The learning based optimization problems are formulated and simulation results are presented. Some open issues are also discussed.
This paper investigates effects of pilot assisted channel estimation on dynamic resource allocation in a multiuser orthogonal frequency division multiplexing (OFDM) system. The channel estimation is done in each OFDM symbol through least-squared error (LSE) or minimum mean-squared error (MMSE) algorithm. The performance of each of these algorithms is evaluated through computer simulations. The maximal...
In this paper, we study bandwidth management of a wireless/optical based access/metro network in support of voice and data services. For voice services, we use a finite state Markov Chain to estimate the blocking probability of voice circuits over an Adaptive modulation and coding wireless channel, as a function of the channel parameters. For data services, we evaluate a rate matching and a buffer...
This paper investigates the effective gain of antennas in indoor channels. A metric called instantaneous effective gain is proposed, and a multiple-cluster 3D channel model is used to facilitate the proposed antenna effective gain. In the multiple-cluster channel model, Laplacian and double exponential distribution are utilized to model azimuth and elevation signal power distribution respectively,...
Cooperative wireless communications offers a new dimension of diversity by emulating transmit antenna diversity to provide reliable communications. In cooperative diversity, single-antenna radios behave as relays between a source and destination, and the performance improvements are due to cooperation of the source and the relay. However, a misbehaving relay can degrade the envisaged performance improvements...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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