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Bit rates in flat-fading OFDM wireless systems can be improved through the use of Adaptive Modulation and Coding (AMC). In this paper, we propose two practical, efficient link adaptation algorithms that use fixed link tables defined by SNR ranges for supported spectral efficiencies. The purpose is to design non-iterative algorithms with acceptable performance and reduced computational complexity relative...
In this paper, we investigate the end-to-end performance of dual-hop multiple-input multiple-output (MIMO) amplify-and-forward (AF) semi-blind relay networks with orthogonal space-time block coding (OSTBC) transmission over mutually independent, non-identically distributed (i.n.i.d.) Nakagami-m fading channels. Our analysis considers a semi-blind relay equipped with a single antenna, and a multiple-antenna...
Image registration as a basic task in image processing was studied widely in the literature. It is an important preprocessing step in different applications such as medical imaging, super resolution, and remote sensing. In this paper we proposed a novel dense registration method based on sparse coding and belief propagation. We used image blocks as features, and then we employed sparse coding to find...
Recurrent neural networks (RNNs) are well known for their capability in minimizing suitable cost functions. Therefore they are used to solve classification and optimization problems in many scientific disciplines. This can be done because they are stable in the sense of Lyapunov. A RNN can be globally or locally stable depending on the fulfilled inherent stability conditions. When using a RNN in an...
In this paper, we introduce the hardware implementation of video acquisition in a sensor node of wireless sensor network with the help of USB 2.0 interface. The USB 2.0 video acquisition is based on the CY7C67300 controller and the DCC1545M image sensor. In this paper, we detail the hardware architecture and the application program design in a sensor node using field-programmable gate array (FPGA)...
Multiple antenna based technology enhances performance of communication system by increasing capacity and reliable detection of the transmitted data. Space-time block codes (STBCs) for multiple-input multiple-output (MIMO) systems are designed to achieve full diversity when transmitter does not have channel state information. Orthogonal space-time block codes (OSTBCs) provide symbol-wise decoding,...
Multiple-Input-Multiple-Output (MIMO) systems are being used in the majority of communication systems because of the capacity advantages that they provide. The correlation value between signals is a parameter that should be carefully considered while planning multi-antenna systems. In this paper, we emphasize the correlation between antenna elements in a multi-antenna system which has the minimum...
In this paper the strategy of Minimum Mean-Squared Error (MMSE) equalization of Discrete Wavelet Transform (DWT) coefficients of received signals is applied in communications receivers. Specifically, the performance of such wavelet-based receivers under a diverse range of conditions is systematically evaluated with the use of Monte Carlo simulations. To determine the robustness of this new type of...
Scalable high speed routers and switches implemented with distributed units introduced a large RTT latency between the line cards and switch fabric, making the crosspoint buffer requirement impractical to provide 100% throughput for unbalanced traffic on combined input and crosspoint queued (CICQ) switches. Crosspoint Queued (CQ)-only switches remove this RTT latency by completely eliminating the...
In cooperative communications, estimation and compensation of multiple carrier frequency offsets is an important implementation issue that needs to be addressed in practice. This paper proposes an efficient maximum likelihood estimator (MLE) using alternating projection technique, for the joint estimation of Rayleigh fading channels and multiple carrier frequency offsets (MCFO) in cooperative communication...
The design of the channel part of a digital communication system (e.g., error correction, modulation) is heavily based on the assumption that the data to be transmitted forms a fair bit stream. However, simple source encoders such as short Huffman codes generate bit streams that poorly match this assumption. As a result, the channel input distribution does not match the original design criteria. In...
Wireless network services are more vigorous than ever due to the rapid development of mobile devices. For this reason, safety critical services such as on-line financial service have now mostly been used through the mobile environment. Recent mobile devices such as smart phones are evolving into multi-purpose handsets having multiple network interfaces and operating in a state that can receive the...
An information exchange problem between two source nodes over a network relay hub is considered where the downlink wireless broadcast channels from the hub to each node are asymmetrical, with different received SNRs. Conventional XOR network coding uses a single downlink FEC with a code rate that protects the node with the smaller received SNR, thereby penalizing the achievable information throughput...
In this paper, we present a noise estimation algorithm using an adaptive smoothing factor based on the Teager energy operator (TEO) energy ratio instead of a voice activity detector (VAD) for a dual-microphone noise suppression system. Conventionally, a dual-microphone noise suppression system consists of two independent systems: a beamformer or adaptive noise canceller (ANC) as a front-end processor...
In this paper, we show how to use a Nintendo Wiimote triaxial accelerometer as an input device to make a gesture recognition system based on Hidden Markov Model as the kernel recognition algorithm. We adopted a set of basic movements called “Fundamental Motions” as the synthesis units for all the other complex motions. In the preliminary study, we tried to discriminate the digits from ‘0’ to ‘9’....
The availability of the Web 2.0 applications in the mobile devices have enabled the users to express sentiments about their invoked services in fast and flexible ways. These sentiments, accessible over the Internet, can greatly influence a potential service user's selection especially in a service rich ambiance. Often, user assisted sentiment analysis can be both costly and inefficient due to the...
Supercapacitors are commonly used energy storage devices in wireless sensor network applications. Two supercapacitor models, the variable leakage resistance (VLR) model and the energy iteration equation (EIE) model, are evaluated by conducting charging-redistribution and self-discharge experiments for a sample supercapacitor, and by simulating a simplified solar powered wireless sensor node. Results...
Cognitive radio networks are promising systems to enable efficient use of spectral resources, thanks to identification of Primary Users (PU) possessing guaranteed radio resources and Secondary Users (SU), trying to use temporary unused channels. Assuming that PU traffic is low, it can switch off specific subcarriers in OFDM signal and this subbands can be used by SU. The proposed method is based on...
This paper proposes a novel receiver, named as “a virtual layered signal processing receiver for 16 QAM” for high speed signal transmission in wireless communication systems. In the proposed receiver, the ordered successive detection is applied with the concept of virtual channel, which enables to detect layered streams even when the number of the layered streams is more than that of the received...
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