10 articles for “frequency offset”

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Research ArticleOpen accessPhrase in the titleANALYSIS OF REDUCTION IN COMPLEXITY OF MULTIPLE INPUT- MULTIPLE OUTPUT-ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEMS WITH CARRIER FREQUENCY OFFSET ESTIMATION AND CORRECTIONSabitha Gauni, Kumar RamamoorthyOrthogonal Frequency Division Multiplexing (OFDM) is a promising research area in Wireless Communication for high data rates. The Multiple Input-Multiple Output (MIMO) technology when incorporated with the OFDM system promise a significant boost in the performance. But, the MIMO-OFDM systems are very sensitive to Carrier Frequency Offset (CFO) as it deteriorates the system performance with the rise of Inter-Carrier-Interference (ICI). … …Journal of Computer Science, Vol. 10, Issue 2 · 13 Nov 2013 · 6,784 accessesView PDF Cite

Research ArticleOpen accessPhrase in the titleA NOVEL TWO STAGE CARRIER FREQUENCY OFFSET ESTIMATION AND COMPENSATION SCHEME IN MULTIPLE INPUT MULTIPLE OUTPUT-ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM USING EXPECTATION AND MAXIMIZATION ITERATIONMalarvezhi Pandy, Kumar RamamoorthyMultiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is a promising technique to handle impairments of multipath channel. Alternatively, one of its major drawbacks is drift in carrier frequency, called Carrier Frequency Offset (CFO). Due to CFO, Inter Carrier Interference (ICI) occurs and results in a large performance degradation. The study proposes a novel two stage CFO estimation and compensation … …Journal of Computer Science, Vol. 9, Issue 11 · 30 Sep 2013 · 6,549 accessesView PDF Cite

Research ArticleOpen accessPhrase in the titleA 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 abstractA 10GHZ Low-Offset Dynamic Comparator for High-Speed and Lower-Power ADCSBakoune Pierre Hypolite, Wembe Tafo Evariste, Moukengue Imano AdolpheThis paper proposed a design of low-voltage Dynamic Comparator using 90 nm PTM CMOS technology for high-speed and Lower-power Analog to Digital Converter (ADC) applications. The double tail structure is employed as based for design new comparator with positive feedback due to best behavior in low-voltage that allows low delay time; decreases the offset voltage and power dissipation. Simulation results … …American Journal of Engineering and Applied Sciences, Vol. 12, Issue 2 · 6 May 2019 · 7,671 accessesView PDF Cite

Research ArticleOpen accessIn the abstractNEURO FUZZY BASED PERFORMANCE ANALYSIS OF MULTIBAND ULTRA WIDE BAND ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEMG. Joselin Retna Kumar, K. S. ShajiThis study proposes an efficient channel-estimation scheme for Multiband (MB) Orthogonal Frequency Division Multiplexing (OFDM)-based Ultra Wide Band (UWB) communication systems. One of the challenges in wireless system is the frequency selective fading caused due to multipath channel between the transmitter and receiver. The signal bandwidth in broad band cellular wireless systems typically exceeds the coherence bandwidth of the multipath … …Journal of Computer Science, Vol. 10, Issue 8 · 5 Mar 2014 · 6,616 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 abstractA Novel Low-Power CMOS Operational Amplifier with High Slew Rate and High Common-Mode Rejection RatioIsmail Nabhan, Moussa AbdallahProblem statement: High speed operational amplifier is always an on-going research topic since major high speed application are needed. Approach: A two-stage operational amplifier (op amp) is designed, simulated and fabricated using a UMC 0.5 μm 2P2M CMOS technology. Results: This chip includes a compensation technique to ensure stability and zero systematic input-offset-voltage. The fabricated chip achieves a 84 dB … …American Journal of Engineering and Applied Sciences, Vol. 3, Issue 1 · 31 Mar 2010 · 8,237 accessesView PDF Cite

Research ArticleOpen accessIn the abstractDesign of Low Phase Noise SIPC based Complementary LC-QVCO for IEEE 802.11a ApplicationHarikrishnan Ramiah, Tun Zainal Azni ZulkifliThe paper presents the design of a source injection parallel coupled (SIPC) quadrature voltage controlled oscillator (QVCO), realized in a complementary architecture, which is usually preferred in low-power applications as it exploits ≈50% bias current reduction with double efficiency compared to the structure with single coupled, when operating in the current-limited regime. A stacked spiral inductor exhibiting a Q factor … …American Journal of Applied Sciences, Vol. 5, Issue 2 · 28 Feb 2008 · 7,295 accessesView PDF Cite

Research ArticleOpen accessIn the abstractComparison of Bit Error Rate Performance of Multi Tone Channel Utilising De-OQPSK and De-Off Set 16 QAM with Guard IntervalIbrahim A.Z. QatawnehDigital communications systems use Multi tone Channel (MC) transmission techniques with differentially encoded and differentially coherent demodulation. Today there are two principle MC application, one is for the high speed digital subscriber loop and the other is for the broadcasting of digital audio and video signals. In this study the comparison of multi carriers with OQPSK and Offset 16 QAM … …Journal of Computer Science, Vol. 1, Issue 3 · 30 Sep 2005 · 6,847 accessesView PDF Cite

Research ArticleOpen accessAll words, across the recordStudy of Cutoff Frequency of High Collector Current Density in SiGe Single-Heterojunction Bipolar TransistorG. M. Khanduri, B. S. PanwarThe cutoff frequency performance of an NPN Si/SiGe/SiGe Single-heterojunction bipolar transistor (SiGe SHBT) at high collector current densities has been analyzed using a 2-dimensional MEDICI device simulator. A conventional NPN Si/SiGe/Si Double-heterojunction bipolar transistor (SiGe DHBT) having uniform 14%Ge in the base region has been investigated for comparison. The analysis shows the formation of a retarding potential barrier for minority … …American Journal of Applied Sciences, Vol. 1, Issue 3 · 30 Sep 2004 · 6,891 accessesView PDF Cite