43 results for “Multipath”

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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 · 6,588 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 abstractNeural Networks for Interferences Suppression in DS/CDMA with Rayleigh Fading Channel and Power Control ErrorY. Jabrane, R. Iqdour, B. Ait Essaid et al.The exponential chip weighting waveforms have been designed with the purpose of multiple access interferences (MAI) rejection based on the concept that the optimum despreading sequence in reference emphasizes the transitions in the received spreading signal of interest. The despreading sequence weighted by exponential chip waveforms was determined by only one parameter. The objective of this study, was to introduce … …Journal of Computer Science, Vol. 3, Issue 3 · 31 Mar 2007 · 6,382 accessesView PDF Cite