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wireless-telecommunication-systems
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Distributed power allocation for OFDM wireless ad-hoc networks based on average consensus
, Article 10th IEEE Singapore International Conference on Communications Systems, ICCS 2006, Singapore, 30 October 2006 through 1 November 2006 ; 2006 ; 1424404118 (ISBN); 9781424404117 (ISBN) ; Khalaj, B. H ; Sharif University of Technology
2006
Abstract
This paper addresses the problem of optimal power allocation in multiuser OFDM ad-hoc networks. Our objective is to maximize the weighted rate-sum of users under total transmit power constraint. Maximizing a weighted rate-sum is more amenable whereas appropriate weight assignment to different users, guarantees fairness among users. We propose a distributed algorithm for optimal power allocation based on reaching a consensus among users for power allocation. The proposed algorithm is tractable in the sense of computational complexity and requires only local information at each node. Simulation results and the analysis of the algorithm are presented to support the proposed idea. © 2006 IEEE
Design concepts and performance analysis of multicarrier CDMA for indoor visible light communications
, Article Journal of Optical Communications and Networking ; Volume 7, Issue 6 , 2015 , Pages 554-562 ; 19430620 (ISSN) ; Fallahpour, A ; Salehi, J. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper, we present a design methodology with implementational insight and evaluate the performance of a multicarrier code-division multiple access (MC-CDMA) system using intensity modulation/direct detection scheme suitable for an indoor visible light communication (VLC) environment. The proposed system is a CDMA system based on an orthogonal frequency division multiplexing (OFDM) platform. To overcome the light-dimming issue, we use a newly proposed methodology, namely, polarity reversed optical OFDM (PRO-OFDM). A unipolar signal is either added to the minimum current or subtracted from the maximum current in the LED linear current range to provide various amounts of dimming. The...
Multiservice provisioning and quality of service guarantee in WDM optical code switched GMPLS core networks
, Article Journal of Lightwave Technology ; Volume 27, Issue 12 , 2009 , Pages 1754-1762 ; 07338724 (ISSN) ; Salehi, J. A ; Sharif University of Technology
2009
Abstract
In this paper, we propose a new scheme to provide multiservice transmission on generalized multiprotocol label switching (GMPLS) networks using optical code-division multiplexing (OCDM) in each wavelength of a wavelength-division multiplexing system. To provide multiservice transmission in a typical GMPLS network, we propose to classify the fiber bandwidth into a number of waveband and consider the wavelengths of each waveband for a specific class-of-service such that the corresponding codes to be used are designed based on the characteristics of the class-of-service. The traffic behavior of the network is examined using Erlang's model, and the probability density functions (PDF) of the...
A combination of MADM and genetic algorithm for optimal DG allocation in power systems
, Article 42nd International Universities Power Engineering Conference, UPEC 2007, Brighton, 4 September 2007 through 6 September 2007 ; 2007 , Pages 1031-1035 ; 1905593368 (ISBN); 9781905593361 (ISBN) ; Afsharnia, S ; Khodayar, M. E ; Rahimikian, A ; Sharbafi, M. A ; Sharif University of Technology
2007
Abstract
Distributed Generation (DG) can help in reducing the cost of electricity to the customer, relieve network congestion, provide environmentally friendly energy close to load centers as well as promote system technical characteristics such as loss reduction, voltage profile enhancement, reserve mitigation and many other factors. Furthermore, its capacity is also scalable and it can provide voltage support at distribution level. The planning studies include penetration level and placement evaluation which are influenced directly by DG type. Most of the previous publications in this field chose one or two preferred parameter as basic objective and implement the optimizations in systems. But due...