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.
In direct sequence (DS) spread spectrum communication system, the first condition of receiving correct data is code synchronization. Synchronization is one of the key techniques in spread spectrum communication systems. This paper presents pseudo-noise (PN) code acquisition and tracking technology. Spread spectrum communication technology is combined with software radio technology to constitute spread...
The network-centric warfare concept pursues information superiority as the key strategic advantage. However, information can have a different strategic value depending on its criticality and, thus, communication systems should provide higher priority to critical data. In this paper, performance of different approaches to achieve such differentiation in TDMA satellite-based tactical communication systems...
A general aim of geometry-based stochastic channel models (GSCMs) is provision of imaginary, but realistic propagation channel responses that can be used as a reference channel in evaluating performance of mobile communication systems. This paper provides an overview of recent development in the GSCMs with particular emphases of 1) structural refinement, 2) parametrization, and 3) validation of the...
In this paper, the problem of identification and recognition of an unknown source of experimental seismic vibrations in real time is described. The influence of different signal delays on frequency spectrum as well as autocorrelation and crosscorrelation functions is examined. It is also illustrated what is the effect of different pulse width on spectrum and correlation functions.
We consider cooperative communications where nodes forward information for each other to achieve reliable communication. Cooperative communication is realized through various protocols such as Decode-and-Forward which are primarily designed with the assumption that nodes are always willing to cooperate. However, in practical systems nodes may violate the rules of cooperation with the selfish intention...
In the nanometer era, the mismatch between the pre-silicon model and the post-silicon timing behavior is becoming severer. Therefore, it is necessary to validate timing with post-silicon data. We propose a method that estimates all the segment delays in the observed paths of a design from post-silicon path delay measurements. Our method is based on equality-constrained least squares methods, which...
Synthesis of quasi-orthogonal ternary sequences (QOTS) with the specified period and peak-factor values on the basis of power residue classes over GF (p) is presented. The distinctive features of the suggested methodology are: • synthesis is performed by a directed search considering necessary existence conditions of QOTS with the defined parameters; • high-speed performance of the synthesis algorithm...
Wireless sensor networks are often deployed in harsh natural environment, in which sensor nodes are vulnerable and therefore produce wrong data. In order to solve this problem, the paper proposes a distributed fault detecting algorithm based on spatio-temporal correlation among data of adjacent nodes. By comparing the sample values of two nodes in short interval, the validity of the data is verified...
In this paper, the nonstationary statistical analysis of data obtained from mobile channel measurement campaign in a suburban environment is presented. The analysis is based on the non-WSSUS concept where the region of stationarity is defined. This region is defined bearing in mind that the interval over which WSSUS can be assumed is limited and dependent on the properties of the transmit signal and...
As the generalized cross-correlation method has high real-time in the delay Algorithm, when the experiment environment is the a priori knowable, Generalized cross-correlation algorithm is usually used. The pre-filtering of the generalized cross-correlation method has a greater impact on the accuracy of time delay estimation, for the problem that how to effectively use the generalized cross-correlation...
In this paper, We applied CCI canceller to remove multiple access interference in co-channel environment and improved performance of Impulse Radio UWB system. Also, we have evaluated the performance of UWB system with Truncated Type-II Hybrid ARQ scheme for achieving high quality data transmission.
The Direct Sequence Spread Spectral (DSSS) communication system has been widely used in military and civilian fields because of its high processing gain, strong ant-jamming and anti-probed capacity, and low intercepted probability. In this paper, an efficient blind parameter estimating and detecting algorithm is proposed, which takes advantage of the autocorrelation property of pseudo random code...
In this paper, airborne experiments of sea surface altimetry using reflected Global Positioning System (GPS) signals is presented. The processing of reflected GPS signal is concerned in detail and a new method of noncoherent summation, which can align coherent correlation outputs of the sea surface reflected GPS signals, is proposed. Results show that relative delay estimation of meter level precision...
The Vehicle Routing Problem with Time Windows (VRPTW) is an important logistics problem which in the real-world appears to be multi-objective. Most research in this area has been carried out using classic datasets designed for the single-objective case, like the well-known Solomon's problem instances. Some unrealistic assumptions are usually made when using these datasets in the multi-objective case...
Hardware Trojans have become a growing concern in the design of secure integrated circuits. In this work, we present a set of novel hardware Trojans aimed at evading detection methods, designed as part of the CSAW Embedded System Challenge 2010. We introduced and implemented unique Trojans based on side-channel analysis that leak the secret key in the reference encryption algorithm. These side-channel-based...
When a large communication network encounters abnormal situations, such as multiple cable cuts or a failure of interface protocol leading to large numbers of propagating alarms may potentially cause many symptom events in multiple network domains. As a result, a network management system may be overwhelmed with a heavy alarm load scenario (a.k.a alarm storm). Appropriate fault management tools are...
Having previously presented a system for simultaneous 3D ultrasound imaging via both temporal bone acoustic windows, we take advantage of this system's scanning geometry to allow each matrix array to serve as a correction source for the opposing array. Aberration is estimated using cross-correlation of RF channel signals followed by least squares solution of the resulting overdetermined system. Delay...
By analyzing the periodicity of autocorrelation functions (ACF) and average magnitude difference functions (AMDF), we present a pitch tracking method based on correlations of mixing ACF & AMDF algorithms. First, we calculate the normalized autocorrelation functions and normalized average magnitude difference functions, and then select a reasonable interpolation parameter from the experiments,...
The modernization process of Global Navigation Satellite System(GNSS) is based on Binary Offset Carrier (BOC) modulation. BOC signals have a better multipath mitigation performance than the legacy BPSK signals. Even though, the position accuracy of GNSS based on BOC signals could not satisfy the requirements of high-precision positioning when multipath signal exists. In this paper, we propose a novel...
Interferometry measurement technology is one of the most important methods for obtaining high precision navigation information in deep space exploration. This paper describes the principle of interferometry measurement wideband correlation signal processing method using bandwidth synthesis technology for accurately extracting the delay of spacecraft angle location information. Bandwidth synthesis...
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.