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Study of signal processing for optical multi-layer disk

IEEE TRANSACTIONS ON MAGNETICS 2007年第2期43卷 840-844页

作者： Maeda, Taksehi Kondou, Masaharu Hitachi Ltd R&D Grp Cent Res Lab Tokyo 1858601 Japan

Research intended to increase the capacity of multi-layer optical disks has frequently applied to multi-layer disks the format for a single layer disk. However, when writing and reading data through non-readout layers, light intensity is fluctuated by data recorded on those layers. To solve this problem, we invented a modulation code, and studied a way to detect data from recorded marks. We report the results of this research here.

关键词： modulation coding optical memory optical recording signal processing

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Signal constellation design for symbol-level rate adaptation in AWGN channels

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IEEE COMMUNICATIONS LETTERS 2007年第11期11卷 836-838页

作者： Christensen, Soren Skovgaard Popovski, Petar Univ Aalborg Dept Elect Syst Aalborg Denmark

This paper considers rate adaptation for the Additive White Gaussian Noise (AWGN)-channel with unknown channel capacity. We show how multi-layer signal constellations can be optimized layer-wise for particular Signal-to-Noise Ratio (SNR)-points, to provide simple and efficient ARQ-based symbol-level rate adaptation with fine granularity. A turbo-coded system is used as an example showing that the proposed design provides actual communication rates that are close to the channel capacity.

关键词： automatic repeat request adaptive modulation modulation coding error correction coding

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Derivative of BICM mutual information

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ELECTRONICS LETTERS 2007年第22期43卷 1219-1220页

作者： Fabregas, A. Guillen Martinez, A. Univ Cambridge Dept Engn Cambridge CB2 1PZ England Eindhoven Univ Technol Dept Elect Engn NL-5600 MB Eindhoven Netherlands

The derivative of the mutual information corresponding to bit-interleaved coded modulation systems is determined. The derivative follows as a linear combination of minimum-mean-squared error functions of a coded modulation set. The result finds applications in the analysis of communications systems in the wideband regime and in the design of power allocation over parallel channels.

关键词： BICM mutual information parallel channel interleaved codes channel coding Codes bit-interleaved coded modulation minimum-mean-squared error function Interpolation and function approximation (numerical analysis) mean square error methods coded modulation set modulation coding power allocation

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An improved technique for suppression of intrachannel four-wave mixing in 40-Gb/s optical transmission systems

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IEEE PHOTONICS TECHNOLOGY LETTERS 2007年第2-4期19卷 67-69页

作者： Batshon, Hussam G. Djordjevic, Ivan B. Vasic, Bane V. Univ Arizona Dept Elect & Comp Engn Tucson AZ 85721 USA

This letter presents an efficient method for testing the efficiency of modulation techniques for countering the effects of intrachannel four-wave mixing by calculating the sum of all the contributors at a given resonance position (the position affected by the surrounding pulses). In addition to this method, we are proposing a modulation technique that shows a significant Q-factor improvement of up to 7.5 dB (depending on the number of spans and the phase sequence implemented) over the uncoded return-to-zero ON-OFF keying. Although the implementation of this phase modulation technique is simple, it is still very efficient in extending the nonlinearity tolerance and enhancing the performance of a high-speed optical transmission system.

关键词： communication system nonlinearities forward-error correction (FEC) low-density parity-check (LDPC) codes modulation coding optical communications optical Kerr effect

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Characters of laser ranging on inter-satellite relative position measurement

Characters of laser ranging on inter-satellite relative posi...

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3rd International Conference on Recent Advances in Space Technologies

作者： Gao Peng You Zheng Tsinghua Univ Dept Precis Instruments & Mechanol Beijing 100084 Peoples R China

ISBN: (纸本)9781424410569

More and more technology innovation and evolution have been used on the small satellite for remote measurement, target searching and tracking missions being performed in space. To achieve relative navigation, relative control intelligently, or to implement some important missions, inter-satellite relative position must be known. In this paper, the measurement procedures of relative position are given. To get precise result of inter-satellite relative position under some specific conditions, laser ranging method should be considered. And the laser ranging method is one of the most valuable methods which should be considered. The principles of laser ranging means and characters of that in space are discussed. Some analysis of this mean is presented. Because of the laser ranging specific characters of application in small satellites formation-flying, some conclusion of laser ranging method will not be suitable for usage in space. The difference of the measurement in space and that in general condition is discussed. Then the modified laser ranging method using code modulation is presented. While, this laser ranging method may require help of other means to achieve the continuous measurement of relative position in some specific missions. Finally, the outlook of the inter-satellite relative position measurement is represented.

关键词： Position measurement Space technology Technological innovation Target tracking Performance evaluation Extraterrestrial measurements Space missions Satellite navigation systems Intelligent control modulation coding

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Evaluation of Welch-Costas frequency hopping pattern for OFDM cellular system

Evaluation of Welch-Costas frequency hopping pattern for OFD...

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18th IEEE International Symposium on Personal, Indoor and Mobile Radio Communication

作者： Wang Chenwei Zhang Xin Yang Dacheng Beijing Univ Posts & Telecommun Wireless Theories & Technol Lab WT&T Beijing 100876 Peoples R China

ISBN: (纸本)9781424411436

The performance of frequency hopped OFDM cellular system depends on the designing of frequency hopping sequences. This paper explores fast frequency hopped OFDM in the link level of a cellular communication system. Each user is assigned several sub-carriers by the base station in each cell in every time slot according to the predetermined hopping sequences. The frequency hopped OFDM technique based on orthogonal hopping sequences can improve communication performance in a cellular system since it could minimize intra-cell interference and average inter-cell interference. In this paper, Welch-Costas Array Pattern is derived under independent and cluster hopping schemes, which enable us to evaluate the system performance with the Turbo code modulation scheme. Examples of the frequency sequences and how they are assigned to users are also given. We also simulate and analyze the impacts of the channel environment and parameters, frequency diversity, and inter-cell interference diversity on the performance of the coded frequency hopped OFDM cellular system.

关键词： Interference Spread spectrum communication Frequency diversity Base stations System performance Turbo codes modulation coding OFDM modulation Analytical models Performance analysis

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MIMO-OFDM Transmission Employing Subcarrier-Block Phase Hopping for PAPR Reduction

MIMO-OFDM Transmission Employing Subcarrier-Block Phase Hopp...

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IEEE 65th Vehicular Technology Conference (VTC-Spring 2007), vol.5

作者： Yusuke Ishida Satoshi Suyama Hiroshi Suzuki Kazuhiko Fukawa Tokyo Institute of Technology Meguro Tokyo Japan

This paper proposes a MIMO-OFDM transmission scheme employing subcarrier-block phase hopping that can reduce peak-to-average power ratio (PAPR) while simultaneously improving transmission performance with low numerical complexity. As a conventional scheme for achieving these objectives, a combination of the enhanced selected mapping (ESLM) and the subcarrier phase hopping for space division multiplexing (SPH-SDM) has been proposed. To reduce the complexity furthermore and to increase feasibility of hardware implementation, the proposed scheme enhances SPH-SDM by introducing subcarrier-block phase hopping based on the partial transmit sequence (PTS). It divides the overall subcarriers into blocks and rotates phases of the complex signals which IFFT generates from the subcarriers of each block. Computer simulations demonstrate that the proposed scheme can drastically reduce PAPR and improve the packet error rate (PER) in comparison with the standard MIMO-OFDM, and that it can achieve almost the same performance as SPH-SDM with ESLM while achieving half as low complexity as that of the conventional one.

关键词： Peak to average power ratio Transmitters Partial transmit sequences Time domain analysis Signal generators Channel coding modulation coding Computer simulation Error analysis Frequency diversity

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Bit and Power Loading Approach for Broadband Multi-Antenna OFDM System

Bit and Power Loading Approach for Broadband Multi-Antenna O...

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IEEE Conference on Vehicular Technology (VTC)

作者： Muhammad Imadur Rahman Suvra Sekhar Das Yuanye Wang Flemming Bjerge Frederiksen Ramjee Prasad Center for TeleInFrastruktur (CTiF) Aalborg University Copenhagen Denmark

In this work, we have studied bit and power allocation strategies for multi-antenna assisted Orthogonal Frequency Division Multiplexing (OFDM) systems and investigated the impact of different rates of bit and power allocations on various multi-antenna diversity schemes. It is observed that, if we cannot find the exact Signal to Noise Ratio (SNR) thresholds due to different reasons, such as reduced Link Adaptation (LA) rate, Channel State Information (CSI) error, feedback delay etc., it is better to fix the transmit power across all sub-channels to guarantee the target Frame Error Rate (FER). Otherwise, it is possible to use adaptive power distribution to save power, which can be used for other purposes, or to increase the throughput of the system by transmitting higher number of bits. We also observed that in some scenarios and in some system conditions, some form of simultaneous bit and power allocations across OFDM sub-channels are required together for efficient exploitation of wireless channel.

关键词： OFDM Diversity methods modulation coding Signal to noise ratio Power distribution Throughput System performance Channel state information State feedback Delay

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An MBOK-UWB SoC transceiver in 0.181μm CMOS technology

An MBOK-UWB SoC transceiver in 0.181μm CMOS technology

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International Conference on ASIC

作者： Sheng Zhang Jianliang Zhang Mengmeng Liu Shuo Wang Liang Heng Runde Zhou Tsinghua Space Centre Tsinghua University Beijing China Institute of Microelectronics Tsinghua University Beijing China Department of Electronic Engineering Tsinghua University Beijing China

A system-on-a-chip (SoC) pulse-based MBOK-UWB transceiver for high-speed wireless transmission is presented in this paper. The system achieves the data rate of 100 Mbps. The digital baseband implements RAKE receiving architecture, with M-ary bi-orthogonal keying (MB OK) spread spectrum modulation, low-density parity-check (LDPC) error-correct coding and Ethernet interface. The front-end circuits include low-power pulse generator, 3~5GHz wideband low-noise amplifier (LNA) and 1 Gsps 4 bit flash analog-to-digital converter (ADC). These modules of proposed SoC has been designed and fabricated in HJTC 0.18 mum 1P6M CMOS technology. The baseband had been designed and implemented in one Xilinx FPGA.

关键词： CMOS technology Transceivers System-on-a-chip Baseband Parity check codes Spread spectrum communication Digital modulation modulation coding Ethernet networks Circuits

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Radio Resource Allocation in Mobile WiMax Networks using Service Flows

Radio Resource Allocation in Mobile WiMax Networks using Ser...

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IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Tara Ali-Yahiya Andre-Luc Beylot Guy Pujolle LIP6 UPMC Paris France ENSEEIHT I. R. I. T. Toulouse France

IEEE802.16e is expected to support mobility for broadband wireless access with the capability of delivering high data rates over long ranges. We consider IEEE 802.216e scheme for scheduling and mapping higher layer data into the basic resource allocation units (slots) of OFDMA frames. Then, we introduce two simple allocation schemes that consider fair allocation among users with adaptive modulation. Both scheduling and mapping approaches are based on the quality of service (QoS) requirements of each service flow in terms of data rate and bit error rate (BER). The performance of both algorithms is studied by simulation. The results show that the proposed algorithms yield fairness among real-time and non real-time service flows as well as guaranteeing their constraint in term of QoS and outage probability.

关键词： Resource management WiMAX Scheduling Quality of service Bit error rate Bandwidth Frequency domain analysis modulation coding MIMO Land mobile radio

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