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Application of transmit diversity for improved robust watermarking

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Journal of Systems Engineering and Electronics 2004年第2期15卷 163-170页

作者： SunRui SunHong YaoTianren DepartmentofElectronicandInformationEngineering HuazhongUniversityofScienceandTechnologyWuhan430074P.R.China DepartmentofCommunicationEngineering WuhanUniversityWuhan430072P.R.China

Many common multimedia signal processing, including cropping, filtering, and perceptual coding, make watermark signal fading-like modification. A scheme that applies transmit diversity technique to improve robustness of digital watermarking is presented. First, the scheme decomposes the original image using wavelet pyramid algorithm and chooses the middle-frequency band for transmission channel that the watermark will be embedded into. Then the watermark is pseudo-randomly permuted. The scheme makes use of space-time coding and differential detection technique to embed and extract watermark. The extracting process has access to neither the original image nor channel state information. Experimental results demonstrate that the scheme improves the performance of robust watermarking.

关键词： digital watermark transmit diversity space-time coding differential detection wavelet transform.

Performance of transmit diversity assisted amplify-and-forward relay system with partial relay selection in mixed Rayleigh and Rician fading channels

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The Journal of China Universities of Posts and Telecommunications 2011年第5期18卷 37-41,46页

作者： XU Wei ZHANG Jian-hua ZHANG Ping Key Lab of Universal Wireless Communication Ministry of Education. Beijhag University of Posts and Telecommunications Beijing 100876 China Wireless Technology Innovation Institute. Beijing University of Posts and Telecommunications Beijing 100876 China

The performance of transmit diversity （TD） assisted amplify-and-forward （AF） relay system with partial relay selection, which experiences mixed Rayleigh and Rician fading channels, is investigated. We first investigate the closed-form expression of the cumulative distribution function for the end-to-end equivalent signal-to-noise ratio （SNR）, and then the exact expressions of outage probability and average symbol error probability （SEP） are derived. The theoretical observations are verified by the Monte Carlo simulation results.

关键词： transmit diversity amplify-and-forward relay Rician fading

Performance of MC-CDMA Systems with Orthogonal transmit diversity over Rayleigh Fading Channel

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Journal of Systems Engineering and Electronics 2003年第3期14卷 33-39页

作者：樊凌涛李高志陈健 Department of Electronic Engineering Shanghai Jiaotong University Shanghai 20030 P. R. China

transmit diversity has been recently proposed to reduce the effects of fading channels in various wireless applications. Orthogonal transmit diersity (OTD) is one of the standardized techniques in 3G systems. In this paper, we apply orthogonal transmit diversity technique to multicarrier CDMA systems. Andlysis and simulation results show that performance benefits can be achieved compared with conventioal MC-CDMA systems in multipath fading channels.

关键词： MC-CDMA transmit diversity Multipath channel Spreading system.

A Novel Space-time Spreading transmit diversity Scheme for Wireless CDMA System

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The Journal of China Universities of Posts and Telecommunications 2004年第2期11卷 72-79页

作者： ZOUYong-zhong LIDao-ben InformationEngineeringSchool BeijingUniversityofPostsandTelecommunicationsBeijing100876P.R.China

This paper presents a new two-branch space-time spreading transmit diversity scheme for wireless CDMA systems, which differs from Space-Time Spreading (STS) of CDMA-2000. Using two transmit and M receiving antennas, the new scheme provides diversity order of 2M. This new technique does not require any bandwidth expansion and any feed back from the receiver to the transmitter and its computation complexity is similar to the Maximal-Ratio Combining (MRC).

关键词： antenna array processing maximal-ratio combining space-time spreading transmit diversity CDMA

CMA Performance in CDMA transmit diversity System

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The Journal of China Universities of Posts and Telecommunications 2005年第4期12卷 61-65页

作者： ZHAO Jing-hua FENG Guang-zeng Nanjlng University of Posts and Telecommunications Nanjing 210003 P.R. China

Plenty of work have been done on Space-Time processing in which multiple transmit / receive antennas are used in conjunction with coding to exploit both spatial diversity and time diversity. Constant Mode Algorithm （CMA） is an efficient blind adaptive Multi-User Detection （MUD） algorithm for CDMA systems. In this paper, we put forward a novel receiver, which combines CMA blind adaptive Multi-user Detection with STBC technique, and compare the performances of the system using different CM algorithms including SDCMA （ Steepest-Descent CMA）, Standard Linearity Confine CMA（SLCCMA） and Least Squares CMA（LSCMA）. Simulations have been done with multi-path Rayleigh channel.

关键词： MIMO transmit diversity Space-Time block coding Multi-User Detection Constant Mode Algorithm SDCMA SLCCMA LSCMA

Performance of the Combining Received Differential Encoding transmit diversity with Imperfect Carrier Recovery over Correlated Nakagami Fading Channels

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Performance of the Combining Received Differential Encoding ...

Cyclic delay transmission for unique word OFDM systems

2003 International Conference on Communication Technology

作者： Guoping FAN Pingyi FAN and Zhigang CAO Department of Electronic Engineering Tsinghua University Beijing 100084

A differential detection scheme for transmit diversity was proposed by Tarokh in [1], which can achieve full diversity order without the requirement to estimate the channel state at the receiver. This

关键词： transmit diversity differential detection carrier recovery bit error rate wireless communications

来源： cnki会议评论

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Science China(Information Sciences) 2014年第8期57卷 78-86页

作者： LIAO Mang XIA XiangGen ZHANG YouGuang School of Electronic Information Engineering Beihang University Department of Electrical and Computer Engineering University of Delaware

In this article,we propose a cyclic delay diversity(CDD)transmission scheme for unique word(UW)OFDM system,which is denoted as CDD-UW-OFDM.In our proposed CDD-UW-OFDM system,the first transmit antenna transmits a UW-OFDM and then,for every UW-OFDM block,the i-th transmit antenna transmits a cyclically delayed version of the symbols transmitted at the first transmit antenna.With this proposed CDD-OFDM system,each antenna transmission is a UW-OFDM.Also,at the receiver under a certain condition on the cyclic delay amounts,the received signal is equivalent to that of a single transmit antenna UW-OFDM transmission with a longer multipath channel.We design the lengths of UW and cyclic delays to achieve the full multipath and spatial diversities for the CDD-UW-OFDM system when the linear MMSE receiver is used.We then present some simulation results to illustrate the claimed performance of the proposed system.

关键词： MIMO-OFDM systems frequency-selective fading channels cyclic delay diversity(CDD) unique word(UW) transmit diversity

An energy-efficient geographic routing based on cooperative transmission in wireless sensor networks

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Science China(Information Sciences) 2013年第7期56卷 42-51页

作者： LI Bin WANG WenJie YIN QinYe LI HongXiang YANG Rong Ministry of Education Key Laboratory for Intelligent Networks and Network Security Xi'an Jiaotong University Department of Electrical and Computer Engineering University of Louisville National Research Institute of Radio Spectrum Management

In this paper, we propose an energy-efficient cooperative geographic routing (ECGR) to reach energy-efficient routing in wireless sensor networks (WSN). ECGR takes full advantage of cooperative diversity and geographic routing. At physical layer, cooperative nodes transmit the same packet in a cooperative way to achieve farther transmission distance of each hop without more energy consumption. While at the network layer, ECGR adaptively selects the appropriate cooperative nodes to form forwarding clusters to forward the packet to the destination when we consider energy consumption and geographic information of the sensor nodes. Meanwhile, in order to fully assess the energy consumption, we take circuit energy consumption of the sensor nodes into consideration. According to the description above, we increase the transmit distance of each hop; and thereby reducing and balancing the overall network energy consumption among nodes to extend the lifetime of the network.

关键词： wireless sensor networks geographic routing transmit diversity multi-sensor diversity circuit energy consumption

Correlation analysis of target echoes using distributed transmit array

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Science China(Information Sciences) 2010年第9期53卷 1860-1868页

作者： JIN Ming*,LIAO GuiSheng & LI Jun National Laboratory of Radar Signal Processing,Xidian University,Xi’an 710071,China National Laboratory of Radar Signal Processing Xidian University Xi’an China

transmit diversity multiple-input multiple-output(MIMO) radars decorrelate target echoes on distributed transmit array,and then through closely spaced receivers array estimate the angles of multiple targets using the received target echoes without separating transmitted signals.In this paper,the target echoes correlation is analyzed under Swerling I and Ⅱ target model assumptions.The results show that:(1) Target echoes are uncorrelated under Swerling II model;(2) under Swerling I model,in order to decrease the correlation of target echoes by increasing the number of transmitters,it is required that the normalized covariance matrices of the signals before and after the transmitter number increases should satisfy a relation given in this study.Finally,the results are verified by computer simulations of the target echoes correlation and angles estimation performance.

关键词： multiple-input multiple-output(MIMO) radar transmit diversity target echoes decorrelation