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digital-communication-systems
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Implementation and optimization of wavelet modulation in additive gaussian channels
, Article 11th International Conference on Advanced Communication Technology, ICACT 2009, Phoenix Park, 15 February 2009 through 18 February 2009 ; Volume 3 , 2009 , Pages 1940-1943 ; 17389445 (ISSN); 9788955191387 (ISBN) ; Nassirpour, S ; Shamsollahi, M. B ; IEEE Communications Society, IEEE ComSoc ; Sharif University of Technology
2009
Abstract
In this paper, we investigate the implementation of wavelet modulation (WM) in a digital communication system and propose novel methods to improve its performance. We will put particular focus on the structure of an optimal detector in AWGN channels and address two main methods for inserting the samples of the message signal in different frequency layers. Finally, computer based algorithms are described in order to implement and optimize receivers and transmitters
Unsupervised, fast and efficient colour-image copy protection
, Article IEE Proceedings: Communications ; Volume 152, Issue 5 , 2005 , Pages 605-616 ; 13502425 (ISSN) ; Kasaei, S ; Sharif University of Technology
2005
Abstract
The ubiquity of broadband digital communications and mass storage in modern society has stimulated the widespread acceptance of digital media. However, easy access to royalty-free digital media has also resulted in a reduced perception in society of the intellectual value of digital media and has promoted unauthorised duplication practices. To detect and discourage the unauthorised duplication of media, researchers have investigated watermarking methods to embed ownership data into media. However, some authorities have expressed doubt over the efficacy of watermarking methods to protect digital media. The paper introduces a novel method to discourage unauthorised duplication of digital...
Analysing of binary PAM systems in digital communication
, Article International Conference on Communication Technology Proceedings, ICCT ; 2012 , Pages 1240-1246 ; 9781467321013 (ISBN) ; Bastani, M. H ; Sharif University of Technology
2012
Abstract
In this era of digital communication systems, different factors are included in efficiency of a transceiver system. Binary PAM systems are one of these transceiver systems. Many aspects of such a system has been considered yet but this field needs more research on because this is the base of any communication system. In this paper, effects of transmitter and receiver filters, noise, duty-cycle and time mismatch between transmitter and receiver in a binary baseband PAM transceiver system is analyzed. Simulation is performed to analyze the above effects on a typical communication system with 10 bits of transmit. MATLAB software is being employed for simulations
Throughput enhancement for repetitive internal cores in latency-insensitive systems
, Article IET Computers and Digital Techniques ; Volume 6, Issue 5 , 2012 , Pages 342-352 ; 17518601 (ISSN) ; Hessabi, S ; Goudarzi, M ; Sharif University of Technology
IEEE
2012
Abstract
Latency-insensitive design (LID) is a correct by-construction methodology for system on chip design that prevents multiple iterations in synchronous system design. However, one problem in the LID is system throughput reduction. In this study, a protocol is proposed to increase the throughput of internal cores in the latency-insensitive systems when there are several repetitive structures. The validation of the protocol is checked for latency equivalency in various system graphs. A shell wrapper to implement the protocol is described and superimposed logic gates for the shell wrapper are formulated. Simulation is performed for 12 randomly generated systems and four actual systems. The...
Adaptive random puncturing based secure block turbo coding
, Article 2010 5th International Symposium on Telecommunications, IST 2010, 4 December 2010 through 6 December 2010 ; December , 2010 , Pages 216-220 ; 9781424481835 (ISBN) ; Payandeh, A ; Aref, M. R ; Sharif University of Technology
2010
Abstract
Reliability and security are two important subjects in modern digital communications. A secure channel coding scheme provides both of reliability and security in one process to combat problems in an unreliable and insecure channel. In this paper, a secure block turbo coding scheme will be proposed and analyzed. Security and reliability are based on pseudo-random puncturing. Simulation results show that this scheme has superior performance and high security
Efficient codebook design for digital communication through compressed voice channels
, Article IET Communications ; Volume 10, Issue 18 , 2016 , Pages 2613-2620 ; 17518628 (ISSN) ; Behnia, F ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
The common voice channels existing in cellular communication networks provide reliable, ubiquitously available and top priority communication mediums. These properties make voice dedicated channels an ideal choice for high priority, real time communication. However, such channels include voice codecs that hamper the data flow by compressing the waveforms prior to transmission. This study designs codebooks of speech-like symbols for reliable data transfer through the voice channel of cellular networks. An efficient algorithm is proposed to select proper codebook symbols from a database of natural speech to optimise a desired objective. Two variants of this codebook optimisation algorithm are...
Stabilization of nonlinear dynamic systems over limited capacity communication channels
, Article IEEE Transactions on Automatic Control ; Volume 65, Issue 8 , 2020 , Pages 3655-3662 ; Farhadi, A ; Seyed Motahari, A ; Hosain Khalaj, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This article addresses the stabilization of noiseless nonlinear dynamic systems over limited capacity communication channels. It is shown that the stability of nonlinear dynamic systems over memory-less communication channels implies an inequality condition between the Shannon channel capacity and the summation of the positive equilibrium Lyapunov exponents of the dynamic system or, equivalently, the logarithms of the magnitude of the unstable eigenvalues of system Jacobian. Furthermore, we propose an encoder, decoder, and a controller to prove that scalar nonlinear dynamic systems are stabilizable under the aforementioned inequality condition over the digital noiseless and the packet...
On distributed transmission of remote correlated Gaussian sources over an orthogonal Gaussian multiple-access channel
, Article 2016 8th International Symposium on Telecommunications, IST 2016, 27 September 2016 through 29 September 2016 ; 2017 , Pages 245-250 ; 9781509034345 (ISBN) ; Behroozi, H ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper, we consider the problem of sending a bivariate correlated Gaussian source through a two-user Gaussian orthogonal multiple-access channel (MAC), where each encoder observes a noisy version of one of the source components, and the receiver aims at reconstructing each source component. The estimation quality is measured by mean-squared error (MSE) distortion criterion. Different components of the source have their own fidelity requirements instead of total or average distortion measure. It is easy to verify that for this problem, digital communication has an optimal performance. However, it is not explicit that when there is a constraint on the total power budget, what power...
Estimation of nonlinear dynamic systems over communication channels
, Article IEEE Transactions on Automatic Control ; Volume 63, Issue 9 , 2018 , Pages 3024-3031 ; 00189286 (ISSN) ; Farhadi, A ; Motahari, A. S ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Remote observation of the state trajectory of nonlinear dynamic systems over limited capacity communication channels is studied. It is shown that two extreme cases are possible: Either the system is fully observable or the error in estimation blows up. The key observation is that such behavior is determined by the relationship between the Shannon capacity and the Lyapunov exponents; the well-known characterizing parameters of a communication channel on one side, and a dynamic system from the other side. In particular, it is proved that for nonlinear systems with initial state x0, the minimum capacity of an additive white Gaussian noise channel required for full observation of the system in...
Capacity bounds and detection schemes for data over voice
, Article IEEE Transactions on Vehicular Technology ; Volume 65, Issue 11 , 2016 , Pages 8964-8977 ; 00189545 (ISSN) ; Boloursaz, M ; Etemadi, S. M ; Behnia, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
Cellular networks provide widespread and reliable voice communications among subscribers through mobile voice channels. These channels benefit from superior priority and higher availability compared with conventional cellular data communication services, such as General Packet Radio Service, Enhanced Data Rates for GSM Evolution, and High-Speed Downlink Packet Access. These properties are of major interest to applications that require transmitting small volumes of data urgently and reliably, such as an emergency call in vehicular applications. This encourages excessive research to make digital communication through voice channels feasible, leading to the emergence of Data over Voice (DoV)...