orthogonal frequency division multiplexing for high speed optical transmission

... equalization and orthogonal frequency- division multiplexing (OFDM) [4]. OFDM is a promising solution for efficiently capturing multipath energy in highly dispersive UWB channels and de- livering high data ... much higher spectral efficiency, for example, 1.2 Gbps, which is 2.5 times higher than the proposed system. We identify several essential requirements to achieve the high rate t ransmission, for ... 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 a data rate up to 480...

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

... algorithm for high speed morpheme extraction, and also de- scribes its implementation on a specific machine. This machine, MEX.I, is designed as the first step 313 A HARDWARE ALGORITHM FOR HIGH ... be- lieve it is suitable for VLSI implementation. Ac- tually, its VLSI implementation is in progress. A high speed morpheme extraction VLSI will im- prove the performance of such text processing ... Step 2 for Procedure 1 are implemented in each state for (a), (b), (c), (d), (e), and so on. In state (a) for Fig. 4, the index memory's out- put expresses the address range for the...

Ngày tải lên: 21/02/2014, 20:20

... Association for Computational Linguistics Randomized Algorithms and NLP: Using Locality Sensitive Hash Function for High Speed Noun Clustering Deepak Ravichandran, Patrick Pantel, and Eduard Hovy Information ... Interestingly, cosine similarity is widely used in NLP for various applications such as clustering. In this paper, we perform high speed similarity list creation for nouns collected from a huge web corpus. ... calculated using the traditional formula as given in equation 1. For this base comparison system we use the one built by Pantel and Lin (2002). We perform 3 kinds of evaluation: 1. Performance of Locality...

Ngày tải lên: 08/03/2014, 04:22

... of configuration E for light undergo- ing up to five reflections. power uniformity of the transmitter has yet to be optimized. For high performance wireless diffuse links with uniform power illumination ... M. H. Elmirg hani, “Spot diffusing technique and angle diversity performance for high speed indoor di ffuse infra-red wireless transmission, ” IEE Proceed- ings: Optoelectronics, vol. 151, no. 1, ... view as well as the power receiving performance. A prototype multibeam transmitter suitable for produc- ing uniform, near hemisphere or 180 degree, high speed, and long distance infrared radiation...

Ngày tải lên: 21/06/2014, 17:20

... degrees of freedom in MIMO channels. Since the multiplexing gain is only available for high SNR region, spatial multiplexing is usually used when high SNR is available. STBC/SFBC [11] assumes ... one is assumed to target high- end users willing to pay more in area and power for performance (e.g., laptops). The MMSE single-mode detector is in favor of low-end users for connec- tivity with ... to 25 dB. For high- end users, SM is preferred when SNR is at least higher than 10 dB. On the other hand, the MMSE mode will consume substantiately lower power than the MFSCO mode, the high- end...

Ngày tải lên: 21/06/2014, 17:20

... the range-cell migration with a high- order range- azimuth coupling form is processed by a nonlinear frequency scaling operation, which is different from the original frequency scaling one. Due to ... nonlinear frequency scaling method is presented. Inspired by the NCS algorithm, the FS operation has been extended to the cubic order to perform a more accu- rate SRC. Before the nonlinear frequency ... f ref = 0 before the frequency scaling operation will simplify the expressions of H FS , H MF ,andH AF . 3. SIMULATION RESULTS In order to evaluate the proposed algorithm, some simula- tions for an...

Ngày tải lên: 21/06/2014, 22:20

... signal modulation experiments have been performed at lower temperatures, but the high speed performance at 85 °C is crucial for most short-distance optical interconnect applications. Thus, we ... simultaneously to a significant lateral compositional modulation and high QD density [34], resulting in a high material and modal gain. For ultrahigh -speed directly modulated VCSEL appli- cations it is extremely ... excellent static performance, i.e. high external efficiency even at 85 °C, these devices demon- strate the potential of this novel active material for temperature stable ultra high speed VCSELs. At...

Ngày tải lên: 22/06/2014, 18:20

... channel conditions, TMAC pro- vides more transmission opportunities for high- rate stations perceiving good channels. This feature is important for high- speed wireless LANs and mesh networks to ... to high- speed wireless networks. The MAC de- sign in high- speed wireless networks, such as IEEE 802.11n, 8 EURASIP Journal on Wireless Communications and Networking Table 3: Analysis results for ... stations, high- rate and low-rate stations, by defining the reference pa- rameters, namely, the reference transmission rate R f and the reference time duration T f . Stations with transmission rates higher...

Ngày tải lên: 22/06/2014, 19:20

Ngày tải lên: 22/06/2014, 22:20

Ngày tải lên: 09/07/2014, 08:16

... High- Speed Dedicated Physical Control CHannel HS-DSCH High- Speed Downlink Shared CHannel HS-PDSCH High- Speed Physical Downlink Shared CHannel HS-SCCH High- Speed Shared Control CHannel HSDPA High- Speed ... Control CHannel HSDPA High- Speed Downlink Packet Access HSPA High- Speed Packet Access HSUPA High- Speed Uplink Packet Access Abbreviations xvii Higher cell capacity and higher spectral efficiency ... radio access has evolved strongly alongside high- speed downlink packet access (HSDPA) and high- speed uplink packet access (HSUPA), together called high- speed packet access’ (HSPA). When the International...

Ngày tải lên: 01/06/2014, 09:38

... multiple access (CDMA) scheme based on strict optical orthogonal codes (SOOC) i s proposed. This scheme is suitable for multiuser high- speed data asynchronous transmission applications because the average ... interval modulation for optical communications,” IEEE Communications Magazine, vol. 36, no. 12, pp. 95–99, 1998. [13] T. Svedek and S. Rupcic, “Anisochronous modulation methods for optical short-range ... Broadcasting (PGNET ’00), pp. 195–200, June 2000. [15] J G. Zhang, “Strict optical orthogonal codes for purely asyn- chronous code -division multiple-access applications,” Applied Optics, vol. 35, no....

Ngày tải lên: 21/06/2014, 08:20

... receivers for optical signals. These opto electronic devices are cheaper as compared to RF equipments. Orthogonal frequency division multiplexing (OFDM) modulation is a promising modulation scheme for ... OFDM systems for DOW transmission, the asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) [7]hasbeen shown to be more efficient in terms of optical power than the ... investigate the use of single carrier frequency domain equalization (SCFDE) over a diffuse optical wireless (DOW) communications. Recently orthogonal frequency division multiplexing (OFDM) has been applied...

Ngày tải lên: 21/06/2014, 08:20

... performance for −40 and 40 dB and obtain better results for G SR /G RD = 0dB as in the individual channel estimation case. We show the BER performance for G SR /G RD ={−40, 0,40}dB,aswellasfortheperfect CSI ... Transactions on Information Theory, vol. 50, no. 12, pp. 3062–3080, 2004. [4] H. Do ˇ gan, “Maximum a posteriori channel estimation for cooperative diversity orthogonal frequency- division multi- plexing ... estimation performance in both approaches. We show the BER and MSE plots in Figures 4(a) and 4(b),respectively,forP ={8, 16,32}.Notice that increasing the number of pilots improves the BER performance...

Ngày tải lên: 21/06/2014, 16:20

... assertion can be proven for the two combiners pro- vided in this paper, for more information see [12]). There- fore, one has to keep in mind that in quasistatic channels the performance gain due to ... 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 channel (i.e., the forward ... QF versus uniform QF All the simulations we performed showed one significant drawback of the uniform QF relaying protocol. Both in static and quasistatic channels, the receiver performance, when...

Ngày tải lên: 22/06/2014, 00:20

... respectively. SIF stands for source input format. HalfD1 stands for video size of 352 ì 480 pixels for one frame. FullD1 stands for 720 ì 480 pixels for one frame. Masayuki Nakamura et al. 5 Japan Nagano Prefecture To ... found to have very high video quality at high compression rates. Taking this result into account, we decided to use (4)-(c) compression format in this drill. As a result, transmission rates between ... compression format of (4)-(f) is used. Therefore, there is almost no delay in video and sound trans- mission. 3.3. A portable live video transmission system Figure 11 shows the portable live video transmission...

Ngày tải lên: 22/06/2014, 06:20

... (2002-03), High Speed Downlink Packet Access: Physical layer aspects, (Release 5)”. [3] B. Sayadi and I. Fijalkow, “Joint detection for multicode trans- mission in downlink high speed UMTS,” ... proposed for a multirate and multicode DS-CDMA system follows the structur al principles of practi- cal downlink UMTS and leads to a convenient algebraic form whichallowsforapowerfulreceiverdesignforamulticode multirate ... MMSE) show good performance. Adding more virtual users brings the conv entional receiver to even worse performance as is shown in Figure 3. For M 1 = 64, the different lines for each receiver type correspond...

Ngày tải lên: 22/06/2014, 22:20