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Attacks On Digital Watermarks: Classification, Estimation-based Attacks And Benchmarks
White Papers We propose a stochastic formulation of estimation-based attacks. Such attacks consist of two main stages: a) watermark estimation; b) exploitation of the estimated watermark to trick watermark detection or create ownership ambiguity.
[April 3, 2004, 0:00]
Estimation Of Rapid Time-Variant Channels For OFDM Using Wiener Filtering
White Papers Moreover, the quality of a model-based channel estimation may degrade if the estimator has been designed for a time-invariant scenario. This paper considers OFDM and pilot-aided channel estimation via Wiener filtering and derives the filter for a...
[October 29, 2004, 0:00]
Improved Channel Estimation For OFDM Based WLAN Systems
White Papers This paper proposes a novel improved channel estimation algorithm for OFDM based WLAN systems. The performance of the proposed channel estimation is demonstrated by computer simulations. Orthogonal Frequency Division Multiplexing (OFDM) has...
[June 19, 2004, 0:00]
Data-Efficient Blind OFDM Channel Estimation Using Receiver Diversity
White Papers This paper investigates non data-aided channel estimation for cyclically prefixed orthogonal frequency division multiplexing (OFDM) systems. In the presence of noise, the proposed method has the desired property of being data efficient - only a...
[October 31, 2004, 23:00]
Beyond 3G: Uplink Capacity Estimation For Wireless Spread-Spectrum Orthogonal Frequency Division Multiplexing (SS-OFDM)
White Papers This paper presents an estimation of the uplink capacity for OFDM using test wireless cellular environment simulations. OFDM has emerged as a potential option for the delivery of broadband wireless. Since its development for military applications...
[October 31, 2004, 23:00]
Optimal Training Signals For MIMO OFDM Channel Estimation In The Presence Of Frequency Offset And Phase Noise
White Papers The authors develop robust Mean-Square Error (MSE)-optimal training signal designs for multiple-input multiple-output orthogonal frequency-division multiplexing channel estimation with frequency offset and Phase Noise (PN), and present analytical...
[April 13, 2007, 0:00]
A Reduced Complexity Channel Estimation For OFDM Systems With Precoding And Transmit Diversity In Mobile Wireless Channels
White Papers A precoding approach for reduced complexity channel estimation for OFDM systems with transmit diversity is presented. Two different OFDM schemes that employ the precoding are investigated: the first one is based on space-time coding, the second is...
[April 13, 2007, 0:00]
A Reduced Complexity, Improved Frequency Offset Estimation For OFDM-Based WLANs
White Papers This paper presents a reduced complexity frequency offset estimation method as a modification to the nonlinear least square (NLS) method. At similar complexity, the estimation performance gain, de-fined as the mean square error ratio between the...
[April 13, 2007, 0:00]
A Combined Timing And Frequency Synchronization And Channel Estimation For OFDM
White Papers This paper addresses training signal based combined timing and frequency synchronization and channel estimation for OFDM systems. Then ML channel estimation is performed. The proposed scheme consists of two stages.
[April 13, 2007, 0:00]
Maximum-Likelihood Carrier Frequency Offset Estimation For OFDM Systems In Fading Channels
White Papers This paper presents two maximum-likelihood CFO estimation schemes, one in frequency domain and another in time-domain, both under Doppler fading. The pr properties of the he estimators are analyzed and simulation results showing the performance...
[April 13, 2007, 0:00]
Pilot-Symbol-Aided Iterative Channel Estimation For OFDM-Based Systems
White Papers This paper proposes a pilot-symbol-aided iterative channel estimation for coded OFDM-based systems. According to their reliabilities, the authors combine these groups to improve the channel estimation.
[April 11, 2007, 0:00]
Obtaining The ZAAP Usage Estimation Information In WebSphere For Z/OS Application Servers
White Papers After the servers have restarted and run for awhile, examine the //SYSOUT DD file of the server address spaces to make certain that zAAP usage estimation data is no longer being written. This white paper documents the procedures required to obtain...
[March 6, 2005, 23:00]
A Pseudorandom Postfix OFDM Modulator - Semi-Blind Channel Estimation And Equalization
White Papers This paper details a new Orthogonal-Frequency-Division-Multiplexing (OFDM) modulator based on the use of a PseudoRandom Postfix (PRP)-OFDM and discusses low-complexity equalization and channel estimation/tracking architectures.
[April 11, 2007, 0:00]
Adaptive Prediction Iterative Channel Estimation For OFDM Signal Reception In A Frequency Selective Fading Channel
White Papers In this paper, pilot-assisted adaptive prediction iterative channel estimation is proposed for the antenna diversity reception of Orthogonal Frequency Division Multiplexing (OFDM) signals. Adaptive prediction filtering is incorporated into...
[April 11, 2007, 0:00]
Blind Carrier Frequency Offset Estimation In SISO, MIMO, And Multiuser OFDM Systems
White Papers The paper shows that this approach can be applied to blind CFO estimation in multi-input multi-output and multiuser OFDM systems. Relying on a kurtosis-type criterion, a low-complexity blind carrier frequency offset (CFO) estimator is developed for...
[March 30, 2005, 0:00]
Pilot-Aided Channel Estimation For Systems With Virtual Carriers
White Papers Further, by exploiting the received data samples at VCs, it describes a novel noise variance estimation method. This paper investigates various frequency-domain channel estimators for Orthogonal Frequency Division Multiplexing (OFDM) systems with...
[April 11, 2007, 0:00]
Fast End-to-End Available Bandwidth Estimation For Real-Time Multimedia Networking
White Papers Dynamic bandwidth estimation serves as an important basis for performance optimization of real-time distributed multimedia applications. The objective of this paper is to develop a bandwidth estimation algorithm for the fast fluctuated Internet.
[May 25, 2007, 0:00]
A Framework For Fine-Granular Computational-Complexity Scalable Motion Estimation
White Papers This paper presents a novel Motion Estimation (ME) framework that offers fine-granular computational-complexity scalability. In the proposed framework, the ME process is first partitioned into multiple search passes.
[May 31, 2007, 0:00]
Visual Basic Applications And Spreadsheet For Teaching Estimation Of Nonparametric Density And Regression Functions
White Papers The specific user functions incorporated into it are easy tools for students to obtain an intuitive perception of nonparametric estimation for density and regression functions. The aim of this paper is to show how teachers can use Visual Basic...
[July 6, 2007, 0:00]
A Rate-One Non-Orthogonal Space-Time Coded OFDM System With Estimation For Frequency Selective Channels
White Papers This paper investigates the impact of applying the channel estimation method to an OFDM system quipped with rate 1 non-orthogonal space time block code for K transmit and 1 receive antenna. A new training pattern based on the Hadamard construction...
[March 30, 2005, 0:00]
