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130 articles for “channel base”
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Research ArticleOpen accessIn the abstractNew Approaches to Ancient Crypto-Steganography MethodsA. Joseph Raphael, V. SundaramProblem statement: The requirement and ability to hide information from others has existed in the world for centuries. Cryptography and steganography are the most commonly used techniques for information sharing. The science of securing a data by encryption is cryptography whereas the method of hiding secret messages in other media is Steganography, so that the secret’s very existence is concealed. … …American Journal of Applied Sciences, Vol. 9, Issue 1 · 4 Nov 2011 · 8,115 accessesView PDFCite
Research ArticleOpen accessIn the abstractA New Approach for Sub-Channels Assignment in Downlink Fourth Generation Mobile SystemsFakhreddine Khelifa, Abdelaziz SametProblem statement: We proposed a new heuristic method for subchannels allocation problem in the context. Approach: In this system, OFDM transmission method has been used, in order to reduce the effect of multipath fading, OFDMA to achieve multiple access schemes and flexibility in resource allocation. Results: An adaptive method for subchannels allocation is necessary in order to exploit the multiuser … …Journal of Computer Science, Vol. 7, Issue 9 · 23 Jul 2011 · 6,593 accessesView PDFCite
Research ArticleOpen accessIn the abstractEnhancing the Color Set Partitioning in Hierarchical Tree (SPIHT) Algorithm Using Correlation TheoryM. Santhi, R. S.D. Wahida BanuProblem statement: Efficient color image compression algorithm is essential for mass storage and the transmission of the image. The compression efficiency of the Set Partitioning in Hierarchical Tree (SPIHT) coding algorithm for color images is improved by using correlation theory. Approach: In this study the correlation between the color channels are used to propose the new algorithm. The correlation between … …Journal of Computer Science, Vol. 7, Issue 8 · 16 Jul 2011 · 6,622 accessesView PDFCite
Research ArticleOpen accessIn the abstractGPS Ionospheric Total Electron Content and Scintillation Measurements during the October 2003 Magnetic StormMohammad Awad Momani, Takialddin A. Al Smadi, Farouq M. Al Taweel, Khaldoon A. GhaidanProblem Statement: Ionospheric scintillations, cause significant effects on satellite signals for communication and navigation in equatorial region and polar regions mainly during sever magnetic storms periods. This phenomenon is not fully understood due to few studies performed. The study investigates variability of Total Electron Content (TEC) and ionospheric scintillation during October 2003 magnetic storm over Antarctica using ground based GPS … …American Journal of Engineering and Applied Sciences, Vol. 4, Issue 2 · 13 Jul 2011 · 8,514 accessesView PDFCite
Research ArticleOpen accessIn the abstractComparison between Vertex Merge Algorithm and Dsatur AlgorithmHandrizal, A. Noraziah, Ahmed N. AbdallaProblem statement: In this study, the channel allocation problem in direct sequence spread spectrum was investigated. First, Coloring in channel allocation has been discussed in detail. Second; a new graph model is proposed that namely Vertex Merge Algorithm (VMA). Approach: VMA try to solve channel allocation based on graph theory. Results: The problem is to assign channel to Access Point … …Journal of Computer Science, Vol. 7, Issue 5 · 7 May 2011 · 7,260 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance Analysis of Global Search Algorithm Based Multiuser Detector for Multi Carrier Code Division Multiple Access System under Clipping NoiseS. Sivanesskumar, R. SukaneshProblem statement: Multi Carrier Code Division Multiple Access (MC-CDMA), a promising technology for the 4G communication systems. The major limitation of MC-CDMA system is the Multiple Access Interference (MAI) which is due to near-far effect, frequency offset and nonlinear power amplification due to clipping noise. Approach: The performance of MC-CDMA under clipping noise using Global search algorithm based Multiuser detector … …Journal of Computer Science, Vol. 7, Issue 5 · 7 May 2011 · 6,690 accessesView PDFCite
Research ArticleOpen accessIn the abstractQuality of Service Policy for IEEE 802.11 Networks with Service Rate Selection based on Fairness IndexLia Toledo Moreira Mota, Alexandre de Assis Mota, Luis Fernando FontolanProblem statement: The IEEE802.11 standard states that all stations have the same probability of accessing the network, but does not consider important parameters such as transmission rates and signal-to-noise ratios. However, these networks present an anomaly that allows a station with a low transmission rate to use the communication channel for a long time. Approach: In this context, this study … …Journal of Computer Science, Vol. 7, Issue 5 · 7 May 2011 · 6,667 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance Analysis of IEEE 802.16d using Forward Error CorrectionVenkatesh Sekar, V. Palanisamy, K. BaskaranProblem statement: Worldwide Interoperability for Microwave Access is the broadband wireless technology for terrestrial broadcast services in Metropolitan Area Networks. This BWA technology is based on Orthogonal Frequency Division Multiplex (OFDM) technology and considers the radio frequency range up to 2-11 GHz and 10-66 GHz. The objective of this research work is the performance analysis of AWGN, SUI-1 and SUI-2 … …Journal of Computer Science, Vol. 7, Issue 3 · 9 Mar 2011 · 7,343 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance Analysis of Multi-user Multi Input Multi Output- Interleave-Division Multiple-Access System Employing Turbo Coding with Multi-User Detection over Frequency-Selective Wireless Communication ChannelKuttathatti Srinivasan Vishvaksenan, R. Seshasayanan, Yuvaraj KrishnamoorthyProblem statement: This study presents the performance analysis of multi-user Multi Input Multi Output (MIMO) assisted interleave based multiple-access system. In IDMA, different interleavers are used to distinguish users as against different signature sequence in a conventional code-Division Multiple-Access (CDMA) scheme. Approach: The basic principle of IDMA is that the interleaver is unique for the users. Results: In this study, … …Journal of Computer Science, Vol. 7, Issue 2 · 25 Feb 2011 · 6,885 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance Evaluation of Multi-Pulse Based Code Excited Linear Predictive Speech Coder with Bitrate Scalable Tool over Additive White Gaussian Noise and Rayleigh Fading ChannelsSuphattharachai ChomphanProblem statement: In the modern speech communication technology, the speech coding with bitrate scalability was needed. However, various types of noises in the communication channels cause damages in the transmitted information especially speech data. Tonal-language speech was also affected by this situation. Approach: Based on the high pitch delay resolution technique, the MPCELP speech coding was proposed over the environment … …Journal of Computer Science, Vol. 6, Issue 12 · 6 Nov 2010 · 7,090 accessesView PDFCite