17 results for “Fading Channels”

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Research ArticleOpen accessIn the abstractReview of Energy Detection for Spectrum Sensing in Various Channels and its Performance for Cognitive Radio ApplicationsR. Suresh Babu, M. SuganthiSpectrum sensing is the basic and important operation in Cognitive Radio (CR) to find the unused spectrum. Energy detector is a popular sensing method because it doesn’t require transmitted signal properties, channel information, of even the type of modulation. This study summarizes the performance result of energy detector over Additive White Gaussian Noise (AWGN), Rayleigh fading and Nakagami fading channels. … …American Journal of Engineering and Applied Sciences, Vol. 5, Issue 2 · 4 Aug 2012 · 7,766 accessesView PDF Cite

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 · 6,687 accessesView PDF Cite

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 · 7,336 accessesView PDF Cite

Research ArticleOpen accessIn the abstractA Preamble-Based Frequency Offset Compensation Scheme in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing SystemsElnaz Ershadi, Hamidreza BakhshiProblem statement: Combining the properties of Multiple Input Multiple Output (MIMO) systems with those of Orthogonal Frequency Division Multiplexing (OFDM), MIMO-OFDM was considered to be a promising technique in the future of wireless communications. However, its sensitivity to frequency offsets which results in Inter-Carrier Interferences (ICIs) makes it necessary to use an exact frequency offset estimation method for data recovery … …Journal of Computer Science, Vol. 6, Issue 4 · 30 Apr 2010 · 7,570 accessesView PDF Cite

Research ArticleOpen accessIn the abstractIterative Channel Estimation Algorithm in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing SystemsMona Nasseri, Hamidreza BakhshiProblem statement: The objective of this study is improving channel estimation accuracy in MIMO-OFDM system because channel state information is required for signal detection at receiver and its accuracy affects the overall performance of system and it is essential to improve the channel estimation for more reliable communications. MIMO-OFDM system was chosen in this study because it has been widely … …Journal of Computer Science, Vol. 6, Issue 2 · 28 Feb 2010 · 8,297 accessesView PDF Cite

Research ArticleOpen accessIn the abstractPerformance of Unequal Error Protection Using Maximum A- posteriori Probability Algorithm and Modified MAP in Additive White Gaussian Noise and Fading ChannelT. Gnanasekaran, K. DuraiswamyProblem statement: In this study we propose a method to improve the performance of Maximum A-Posteriori Probability Algorithm, which is used in turbo decoder. Previously the performance of turbo decoder is improved by means of scaling the channel reliability value. Approach: A modification in MAP algorithm proposed in this study, which achieves further improvement in forward error correction by means … …Journal of Computer Science, Vol. 4, Issue 7 · 31 Jul 2008 · 6,686 accessesView PDF Cite

Research ArticleOpen accessAll words, across the recordA 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 · 6,588 accessesView PDF Cite