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33 results for “OFDM System”

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Research ArticleOpen accessIn the abstractSymbol Timing Estimation in Multiband Orthogonal Frequency Division Multiplexing based Ultrawide band SystemM. N. Suresh, S. J. Thiruvengadam, V. AbhaikumarProblem statement: The Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) Based Ultra Wideband system (UWB) is highly susceptible to symbol timing error. Symbol timing estimation in MB-OFDM based UWB is difficult due to the presence of strongest path at delayed instant. Approach: Symbol timing estimation has two steps namely a coarse estimation and a fine estimation. In this study, a maximum … …American Journal of Applied Sciences, Vol. 9, Issue 4 · 10 Feb 2012 · 7,101 accessesView PDFCite
Research ArticleOpen accessIn the abstractMultiple Input Multiple Output System with Space Time Block Coding and Orthogonal Frequency Division MultiplexingP. Ramesh Kumar, R. M.S. ParvathiProblem statement: A large amount of research has been performed to achieve very high data rate networks to support reliable transmission of video, data and speech at high rates to many users. One way to increase the data rate in a wireless system is to use multiple transmit and/or receive antennas (MIMO structure). Indeed, it has been shown that the … …Journal of Computer Science, Vol. 8, Issue 4 · 26 Jan 2012 · 6,759 accessesView PDFCite
Research ArticleOpen accessIn the abstractA Comparative Performance Analysis of Multiple-Input Multiple-Output using MATLAB with Zero Forcing and Minimum Mean Square Error EqualizersBara'u Gafai Najashi, Tan XiaohengProblem statement: Multiple-Input Multiple-Output systems (MIMO) were regarded as one of the most promising technologies in field of wireless communication. Generally considered as one of the several forms of smart antenna technology, it offers considerable increase in data throughput and link range without additional bandwidth or transmit power. The general idea involves the use of several antennas at the transmitter … …American Journal of Engineering and Applied Sciences, Vol. 4, Issue 3 · 29 Nov 2011 · 8,298 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 · 6,588 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance of Orthogonal Frequency Division Multiplexing System Based on Mobile Velocity and SubcarrierZulkeflee Bin Khalidin, Haitham J. TahaProblem statement: Nowadays, the mobile telecommunications industry faces the problem of providing the technology that be able to support a wide variety of services ranging from voice communication with a bit rate of a few kbps to wireless multimedia in which bit rate up to 2 Mbps. Approach: This study introduced a new performance study to enhance the Orthogonal Frequency … …Journal of Computer Science, Vol. 6, Issue 2 · 28 May 2010 · 7,037 accessesView PDFCite
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 PDFCite
Research ArticleOpen accessIn the abstractOn-Chip Implementation of High Resolution High Speed Floating Point Adder/Subtractor with Reducing Mean Latency for OFDMRozita Teymourzadeh, Yazan Samir Algnabi, Nooshin Mahdavi, Masuri Bin OthmanProblem statement: Fast Fourier Transform (FFT) is widely applied in OFDM trance-receiver communications system. Hence efficient FFT algorithm is always considered. Approach: This study proposed FPGA realization of high resolution high speed low latency floating point adder/subtractor for FFT in OFDM trance-receiver. The design was implemented for 32 bit pipelined adder/subtractor which satisfied IEEE-754 standard for floating-point arithmetic. The design … …American Journal of Engineering and Applied Sciences, Vol. 3, Issue 1 · 31 Mar 2010 · 7,924 accessesView PDFCite
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 PDFCite
Research ArticleOpen accessIn the abstractHardware Implementation of a Genetic Algorithm Based Canonical Singed Digit Multiplierless Fast Fourier Transform Processor for Multiband Orthogonal Frequency Division Multiplexing Ultra Wideband ApplicationsMahmud Benhamid, Masuri B. OthmanProblem statement: Ultra Wide Band (UWB) technology has attracted many researchers' attention due to its advantages and its great potential for future applications. The physical layer standard of Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM) UWB system is defined by ECMA International. In this standard, the data sampling rate from the analog-to-digital converter to the physical layer is up to 528 … …Journal of Mathematics and Statistics, Vol. 5, Issue 4 · 31 Dec 2009 · 7,515 accessesView PDFCite
Research ArticleOpen accessIn the abstractEfficient Detection Algorithm for a Multiple-Input and Multiple-Output Multiuser Multi-Carrier Code Division Multiple Access in Time-Varying ChannelsFares Sayadi, Mahamod Ismail, Norbahiah Misran et al.Problem statement: Maximum Likelihood (ML) decoding has been applied for the uplink of a Multi-Carrier Code Division Multiple Access (MC-CDMA) system based on Orthogonal Frequency Division Multiplexing (OFDM). Multiple-Input Multiple-Output (MIMO) channel from k users, which moves at vehicular speed, to the Base-Station (BS) is time-varying. For time-varying channels, Sphere Decoding (SD) was introduced to perform ML decoding. Whereas, computational … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 4 · 31 Dec 2009 · 7,576 accessesView PDFCite