The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Outage performance of distributed transmit-receive diversity system subjected to composite Rayleigh-Lognormal fading channel is considered. Using random Wishart matrix theory and Gauss-Hermite quadrature, we derived closed form expressions for its outage probability. The theoretical expressions are validated by numerical results. It is show that distributed transmit-receive system promise significant...
Device-to-Device (D2D) communication underlaying cellular networks can improve resource utilization and thus increase total throughput. However, resource allocation and interference coordination between cellular networks and D2D system will become critical and need to be properly handled. According to some papers, which just allowed a set of cellular user equipment (UE) and a pair of D2D UEs to coexist...
Signaling storm happened frequently around the world in the recent years, which caused the network congestion, and then affected the user's normal communication. The signaling storm resulted from the large number of signaling consumption that were used for frequent RRC connections. In this paper, we presented a RRC connection release control method to control the user's frequent connection in the...
In order to improve accuracy and reliability of wireless location in the mixed line-of-sight (LOS) and non-line-of-sight (NLOS) environment, a real-time NLOS identification and LOS reconstruction algorithm in connection with the positive characteristic of the NLOS error are presented to estimate the position of a mobile station (MS). A kalman filter (KF) based on innovation vectors is utilized to...
Discrete cosine transform (DCT)-based channel estimator has the capacity to cope with aliasing error caused by discrete fourier transform (DFT)-based method. Nonetheless, the noise within the considered channel taps will degrade the performance of this algorithm. In this paper, a new DCT-based channel estimation algorithm using wavelet denoising technology in LTE uplink systems is proposed. Wavelet...
With the increasing demand on wireless communications operating at the shared and unlicensed Industrial, Scientific and Medical (ISM) band of 2.4 GHz, the coexistence problem is one of the most important issues. Wireless Sensor Networks (WSNs) based on the IEEE802.15.4 standard are among such systems which are being affected. For the past years, the idea of multi-channel utilization has been highly...
In this paper, distributed estimation over an orthogonal multiple-access channel (MAC) wireless sensor network (WSN) is investigated where the sensors transmit with phase-modulated signals through independent and identically complex Gaussian channels. The maximum-likelihood (ML) estimator for ideal sensing environment and the corresponding modified Cramer-Rao lower bound are derived, and the estimation...
A low complexity serial Fast Fourier Transform Belief Propagation (FFT-BP) algorithm for decoding non-binary low-density parity-check (LDPC) codes use unsymmetrical message transmission scheme between bit nodes and check nodes is presented. Before each step of iteration, every symbol node's reliability was evaluated based on high reliable check number and pseudo a posterior probability (APP). The...
In most of existing attacker detection algorithms for collaborative spectrum sensing (CSS) systems, attacking strategies are assumed to be uniform (identical). However, when non-uniform attacking strategies are adopt, the diversity of attacking strategies make it difficult to isolate the attackers. In this paper, to detect the non-uniform strategy attackers, we use the dissimilarity metric of a cognitive...
A voltage reference with low temperature coefficient (TC), low supply voltage and ultra-low power consumption is presented. The proposed reference is made up of MOSFETs working in subthreshold region without resistors. Therefore the advantages of ultra-low power consumption and ultra-small area can be obtained. The best TC is 2.1ppm/°C in a temperature range of −20°C to 80°C. The supply voltage ranges...
Evaluating the power consumption of cache in an early time is very important for designer to judge their system whether meets the constraints of power. An improved cache power model is proposed to simulate the peak power of cache according to the system parameters. Compared with the traditional power model, it additional supports leakage power, routing power, and multi-port cache. Process scaling...
The increasing complexity of systems poses a big challenge to design systems with fault-tolerant capability. The aim of this study was to establish fault-tolerant system for multiprocessor platform with the help of hierarchical scheduling framework. A mathematical fault and reliability model for hierarchical scheduling framework was proposed firstly, and then a heuristic algorithm by exploiting the...
This paper presents a project of an intelligent home system based on the Internet of Things. The proposed system provides various convenient services for residents and constructs a network with every single intelligent home node. In this paper, firstly, an intelligent home gateway is described in detail. A number of home sensors, based on Zigbee technology, can be deployed in the house. Various intelligent...
In conventional binary network coding (BNC), the decode condition constrains the achievement of diversity gain. In this paper, a novel network-coded scheme is proposed, where the inter-rely cooperation (IRC-NC) is employed to loose the above restriction. Firstly, two relays are divided into NC node and assistant node according to their channel gain to destination. This process is accomplished by the...
We investigate the vulnerability of complex networks under different node-based attacks. The networks considered include scale-free network (SF), WS small-world network model, ER network and two real-world networks (autonomous system network and Italy power grid). The attacks are induced by removing the nodes in the descending order of the four kinds of weights defined in this paper. By measuring...
In this paper, we consider adaptive cooperation and relay selection for opportunistic system. A novel hybrid opportunistic cooperation strategy with log likelihood ratio (LLR) threshold is proposed in order to combat error propagation. Firstly, we combine the proactive and reactive opportunistic relaying by employing specific LLR switching thresholds, according to which the best relay and the corresponding...
As the inevitable noises exist in actual application, the common method (MTMM) gets unacceptable result of singularity detection. In order to get more accurate singularity detection, wavelet transform shrinkage and spatially selective noise filtration methods are respectively utilized to denoise the corrupted signals. Then, the wavelet transform are applied to the two independent preprocessing signals,...
This paper proposes a low complexity crossover digital predistorter (CO-DPD) to compensate the nonlinear effects due to the power amplifier (PA) and crosstalk interference in a 2×2 space frequency block code (SFBC) orthogonal frequency division multiplexing (OFDM) systems. The computational complexity of both conventional CO-DPD and our low complexity CO-DPD is computed and compared. We evaluate the...
In this paper, we gave a brief discussion of the expanded time and frequency OFDM (ETF-OFDM) system and its traditional synchronization method (the Schmidl's method). And then we present a rapid frame and symbol synchronization algorithm in this system for just detecting one training symbol instead of two training symbols in Schmidl's method. The algorithm has low calculation complexity and outperforms...
Based on imperfect channel state information (CSI), the performance analysis of multiuser multiple-input multiple-output (MIMO) system with rate adaptive modulation (AM) and antenna selection is presented. By means of approximate expression of bit error rate (BER) under imperfect CSI, the variable switching thresholds (ST) subject to a target BER constraint are derived. By the ST, a tightly approximate...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.