orthogonal frequency division multiplexing ppt

... 2006 One of the UWB proposals in the IEEE P802.15 WPAN project is to use a multiband orthogonal frequency- division multiplexing (OFDM) system and punctured convolutional codes for UWB channels supporting ... inter-symbol interference (ISI) caused by multipath channels are equalization and orthogonal frequency- division multiplexing (OFDM) [4]. OFDM is a promising solution for efficiently capturing multipath ... May 2002. [4] L. J. Cimini Jr., “Analysis and simulation of a digital mobile channel using orthogonal frequency division multiplexing, ” IEEE Transactions on Communications, vol. 33, no. 7, pp. 665– 675,...

Ngày tải lên: 22/06/2014, 22:20

Ngày tải lên: 26/05/2013, 21:28

Ngày tải lên: 11/07/2014, 20:21

Ngày tải lên: 16/10/2014, 21:48

Ngày tải lên: 09/07/2014, 08:16

... the chunk resources, so-called frequency- adaptive (FA) transmission [9]. Adaptive Orthogonal Frequency Division Multiple Access (OFDMA) with a chunk-based Time Division Multiple Access (TDMA) ... equidistantly frequency- separated blocks, each consisting of a few subcarriers, are allocated to each user. A Discrete Fourier Transform (DFT) pre- coding step is performed on each Orthogonal Frequency- Division ... described in [13], also denoted as Interleaved Frequency Division Multiple Access (IFDMA) in the original paper [14]or Single-Carrier Frequency Division Multiple Access (SC- FDMA) with distributed...

Ngày tải lên: 21/06/2014, 22:20

... to multiple users. Types of Multiplexers: 1. FDM Frequency Division Multiplexing 2. TDM Time Division Multiplexing Frequency Division Multiplexing: (Chapter-3) ã FDM is an analog technique ... using their own lane. This sharing by frequency band is known as Frequency division Multiplexing (FDM). ã Sharing one media by multiple users is known as multiplexing. If the number of users ... serial port, is actually an inverse multiplexer. Wavelength Division Multiplexing (WDM) - is the nothing but the Frequency division Multiplexing. But this is called WDM because the combination...

Ngày tải lên: 10/12/2013, 08:15

... Coarse Wavelength Division Multiplexing (CWDM) Generate More Revenue with Less Fiber Here's How it Works In simple ... MDU/ BUSINESS Satellite Uplink F i b e r L i n e W a v e l e n g t h s The CWDM Advantage ADC Coarse Wave Division Multiplexing (CWDM) Solutions, part of the ADC’s Value-Added Module (VAM) family, add flexibility...

Ngày tải lên: 21/12/2013, 07:17

... Page 2 ADC Coarse Wavelength Division Multiplexing CWDM VAM Module Ordering Guide and Information Catalog Number CW __ __ __ - __ ... EightChannelStandard1470nm,1490nm,1510nm,1530nm,1550nm,1570nm,1590nm, 1610with1310nmupgrade. Page 4 ADC Coarse Wavelength Division Multiplexing CWDM VAM Module Ordering Guide and Information Application #1: Ordering a MicroVAM ... nm 1530 nm 1510 nm 1330 nm Common Port or Input Optical Components Page 6 ADC Coarse Wavelength Division Multiplexing CWDM VAM Module Ordering Guide and Information CWDM Module Types WideVAM đ VMW UsedwithADC8"FCMandindustry- standard...

Ngày tải lên: 17/01/2014, 11:20

... Germany stefan.evert@uos.de Abstract Frequency distribution models tuned to words and other linguistic events can pre- dict the number of distinct types and their frequency distribution in samples ... model’s success in predicting V does not necessary imply that the model is also capturing the right frequency distribution). For all models, corpora and prediction sizes, goodness-of-fit of the model ... Computational Linguistics Words and Echoes: Assessing and Mitigating the Non-Randomness Problem in Word Frequency Distribution Modeling Marco Baroni CIMeC (University of Trento) C.so Bettini 31 38068...

Ngày tải lên: 17/03/2014, 04:20

... which employ orthogonal relay channels, where the orthogonality is often accomplished through time division. Cooperative relay systems with orthogonal cha nnels typically either employ multiple orthogonal ... distributed space -frequency code. The three DSTCs in [15] and the distributed space -frequency code in [16] can achieve both cooperative diversity and frequency diversity where the frequency diversity ... 765–779 (2005). doi:10.1109/TIT.2004.842566 22. A Medles, D Slock, Optimal diversity vs multiplexing tradeoff for frequency selective MIMO channels. in International Symposium on Information Theory (ISIT’05)...

Ngày tải lên: 20/06/2014, 22:20

... incidence. Then, the frequency response is only a function of the time-delay τ mn between each source and sensor H mn ( k ) = e j2πf k τ mn , (4) f k being the frequency corresponding to frequency index ... rarely overlap at each time- frequency point, (2) can be simplified as follows: X m ( k, r ) ≈ H ma ( k ) S a ( k, r ) , (3) where S a (k, r) is the dominant source at time -frequency point (k, r). ... microphone signal, being k and r the frequency index and time frame index, respectively. S n (k, r) denotes the STFT of the source signal s n (t)andH mn (k) is the frequency response from source n...

Ngày tải lên: 21/06/2014, 08:20

... the state codebook C 8 is given by C 8 = { F 8 , F 5 , F 4 , F 6 }. In the context of orthogonal frequency division multi- plexing (OFDM), this approach has already been proposed in [28] to compress ... unitary precoding for orthogonal space-time block codes,” IEEE Transactions on Signal Processing , vol. 53, no. 1, pp. 64–73, 2005. [17] G. Leus, C. Simon, and N. Khaled, “Spatial multiplexing with ... 1/ √ 2   VV H −FF H   F =  tr  I N S −V H FF H V  . (13) This function is related to the performance of an orthogonal space-time block code (OSTBC) that is used on top of the precoder [16]. For all the above...

Ngày tải lên: 21/06/2014, 22:20

... reproduction in any medium, provided the original work is properly cited. 1. Introduction Orthogonal frequency division multiplexing (OFDM) has been widely accepted as an enabling technology for next generation ... for complex equalization. OFDM also forms the foundation for a multiple access scheme termed as orthogonal frequency division multiple access (OFDMA). In OFDMA, each user is assigned a fraction of available ... model to describe the time /frequency variation of each channel coefficient. Therefore, the spaced frequency (Δ f ) spaced time (Δt) correlation function of the channel frequency response can be...

Ngày tải lên: 21/06/2014, 23:20

... w rd (n), (2) where the notation is dened above. Orthogonality between the received cooperation signal y rd and direct signal y sd can be implemented by frequency division (FD). The optimal bandwidth allocation ... in this paper are quasistatic orthogonal relay channels for which orthogonality is defined accordingly to [1]. Since the source-destination channel is assumed to be orthogonal to the relay-destination ... pages doi:10.1155/2007/20258 Research Article Practical Quantize-and-Forward Schemes for the Frequency Division Relay Channel B. Djeumou, 1 S. Lasaulce, 1 and A. G. K lein 2 1 CNRS, Sup ´ el ´ ec,...

Ngày tải lên: 22/06/2014, 00:20

Ngày tải lên: 22/06/2014, 15:19

... â 2007 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION The orthogonal frequency division multiplexing (OFDM) system has enjoyed great success in many wideband com- munication ... more than 8 dB. Thus the incorporation of frequency criteria results in a loss of SIR by 7 dB. To show the improvement in frequency response when the frequency criteria are applied, we plot the ... impose frequency criteria. The heav- ier the frequency criteria, the lower the SIR. Comparing the cases of c = 10 and c = 0, the loss of SIR (after 200 iterations) is around 6 dB. Even with the frequency...

Ngày tải lên: 22/06/2014, 23:20

... broad- band transmission, the complexity of equalization in TD will be very high. Orthogonal frequency division multiplexing (OFDM) transmission [1] that can be considered as a one- tap linear ... technique to eliminate ISI is single- carrier modulation with a cyclic prefix (CP) and frequency domain (FD) equalization. Frequency domain linear equal- izers (FDLE) proposed in [2, 3, 4] make this technique ... detection procedure to the ith sub- stream, MIMO frequency- selective channels are reduced to equivalent parallel single-input multiple-output frequency- selective channels. Therefore, the initialization...

Ngày tải lên: 23/06/2014, 01:20

Ngày tải lên: 27/06/2014, 01:21

Ngày tải lên: 08/07/2014, 02:20