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Proceedings of the 1999 advanced signal processing algorithms, architectures, and implementations IX

作者： Kayhan, A. Salim Amin, Moeness G. Hacettepe Univ Ankara Turkey Villanova Univ United States

In this paper, we use the concept of evolutionary spectrum to solve key problems in array processing. We present Cross-power Evolutionary Periodogram for direction finding and blind separation of nonstationary signals. We model nonstationary signals received by each sensor in the array as a sum of complex sinusoids with time-varying amplitudes. These amplitudes carry information about the direction of arrival which may also be time-varying. We first estimate the time-varying amplitudes, then use the results for the estimation of evolutionary cross-power distributions of the sensor data. Next, using cross-power estimates at time-frequency samples of interest, we estimate the directions of arrival using one of the existing high resolution direction finding methods. If the directions are time-varying, we select time-frequency points around the time of interest. By carrying out the estimation at different times, we obtain the directions as a function of time. If the sources are stationary, then we can use all time-frequency points of interest for the estimation of fixed directions. We also use whitening and subspace methods to find the mixing matrix and separate the signals received by the array. Simulation examples illustrating the performances of the proposed algorithms are presented.

关键词： Parallel processing systems

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Classification of vehicles using nonlinear dynamics and array processing

Classification of vehicles using nonlinear dynamics and arra...

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Proceedings of the 1999 advanced signal processing algorithms, architectures, and implementations IX

作者： Tung, Tai-Lai Yao, Kung Univ of California Los Angeles Los Angeles United States

The analysis of vehicle signals with methods derived from the theory of nonlinear dynamics is a potential tool to classify different vehicles. The nonlinear dynamical methodologies provide alternate system information that the linear analysis tools have ignored. In order to observe the nonlinear dynamic phenomena more clearly, and estimate system invariants more robustly, we exploit the maximum power blind beamforming algorithm as a signal enhancement and noise reduction method when locations of a source and sensors are unknown. The dynamical behavior of an acoustic vehicle signal is studied with the use of correlation dimension D2 and Lyapunov exponents. To characterize the nonlinear dynamic behavior of the acoustic vehicle signal, Taken's embedded theory is used to form an attractor in phase space based on a single observed time series. The time series is obtained from the coherently enhanced output of a blind beamforming array. Then the Grassberger-Procaccia algorithm and Sano-Sawada method are exploited to compute the correlation dimension and Lyapunov exponents. In this paper, we also propose some efficient computational methods for evaluating these system invariants. Experimental classification results show that the maximum power blind beamforming processing improves the estimation of the invariants of the nonlinear dynamic system. Preliminary results show that the nonlinear dynamics is useful for classification applications.

关键词： Acoustic signal processing

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Minimal-window time-frequency distributions

Minimal-window time-frequency distributions

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Proceedings of the 1999 advanced signal processing algorithms, architectures, and implementations IX

作者： Williams, William J. Aviyente, Selin Univ of Michigan Ann Arbor United States

This paper outlines means of using special sets of orthonormally related windows to realize Cohen's class of time-frequency distributions (TFDs). This is accomplished by decomposing the kernel of the distribution in terms of the set of analysis windows to obtain short time Fourier transforms (STFTs). The STFTs obtained using these analysis windows are used to form spectrograms which are then linearly combined with proper weights to form the desired TFD. A set of orthogonal analysis windows which also have the scaling property proves to be very effective, requiring only 1 + log2(N - 1) distinct windows for an overall analysis of N + 1 points, where N = 2n, with n a positive integer. Application of this theory offers very fast computation of TFDs, since very few analysis windows needed and fast, recursive STFT algorithms can be used. Additionally, it is shown that a minimal set of specially derived orthonormal windows can represent most TFDs, including Reduced Interference Distributions (RIDs) with only three distinct windows plus an impulse window. Finally, the Minimal Window RID (MW-RID) which achieves RID properties with only one distinct window and an impulse window is presented.

关键词： signal processing

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Real-time implementation of the multistage detector for next generation wideband CDMA systems

Real-time implementation of the multistage detector for next...

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Proceedings of the 1999 advanced signal processing algorithms, architectures, and implementations IX

作者： Xu, Gang Cavallaro, Joseph R. Rice Univ Houston United States

The multistage detection algorithm has been widely accepted as an effective interference cancellation scheme for next generation Wideband Code Division Multiple Access (W-CDMA) base stations. In this paper, we propose a real-time implementation of this detection algorithm in the uplink system, where we have achieved both high performance in the interference cancellation and computational efficiency. When interference cancellation converges, the difference of the detection vectors between two consecutive stages is mostly zero. We recode the estimation bits, mapping from ±1 to 0 and ±2. Bypassing all the zero terms saves computations. Multiplication by ±2 can be easily implemented in hardware as arithmetic shifts. The system delay of a three-stage detector can be reduced by half with satisfactory bit error rate. We also propose a vLSI implementation of this algorithm that has the potential of real-time performance. The detector handling up to eight users with 12-bit fixed point precision was fabricated using a 1.2 μm CMOS technology.

关键词： Digital signal processing

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High-performance FFT implementation on the BOPS ManArray parallel DSP

High-performance FFT implementation on the BOPS ManArray par...

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Proceedings of the 1999 advanced signal processing algorithms, architectures, and implementations IX

作者： Pitsianis, Nikos P. Pechanek, Gerald BOPS Inc Chapel Hill United States

We present a high performance implementation of the FFT algorithm on the BOPS ManArray parallel DSP processor. The ManArray we consider for this application consists of an array controller and 2 to 4 fully interconnected processing elements. To expose the parallelism inherent to an FFT algorithm we use a factorization of the DFT matrix in Kronecker products, permutation and diagonal matrices. Our implementation utilizes the multiple levels of parallelism that are available on the ManArray. We use the special multiply complex instruction, that calculates the product of two complex 32-bit fixed point numbers in 2 cycles (pipelinable). Instruction level parallelism is exploited via the indirect very Long Instruction Word (ivLIW). With an ivLIW, in the same cycle a complex number is read from memory, another complex number is written to memory, a complex multiplication starts and another finishes, two complex additions or subtractions are done and a complex number is exchanged with another processing element. Multiple local FFTs are executed in Single Instruction Multiple Data (SIMD) mode, and to avoid a costly data transposition we execute distributed FFTs in Synchronous Multiple Instructions Multiple Data (SMIMD) mode.

关键词： Parallel processing systems

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Design and implementation of viterbi decoder with FPGAs

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JOURNAL OF vLSI signal processing SYSTEMS FOR signal IMAGE AND vIDEO TECHNOLOGY 1999年第1期21卷 5-14页

作者： Kivioja, M Isoaho, J vänskä, L Tampere Univ Technol Digital Media Inst FIN-33101 Tampere Finland Royal Inst Technol Dept Elect SE-16440 Kista Sweden Nokia Res Ctr FIN-00211 Helsinki Finland

In this paper we present our studies for implementing complex DSP and Telecom systems in FPGAs. We analyse suitability of FPGA device architectures for implementing complex algorithms. Here we use a viterbi algorithm as a deeper case study. Different architectural strategies for implementations are discussed and analysed with the special emphasis on practical FPGA implementations. Speed performance, easy routability and minimisation of inter-chip communication are used as design criteria. viterbi decoder, constraint length seven, was designed and simulated with vHDL in Synopsys and Mentor tool environments and further implemented on four Xilinx 4028EX devices using trace-back based architecture. Also partitioning aspects of the decoding algorithm are presented and analysed.

关键词： signal encoding

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Design and Implementation of viterbi Decoder with FPGAs

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Journal of vLSI signal processing systems for signal, image and video technology 1999年第1期21卷 5-14页

作者： Kivioja, M. Isoaho, J. vänskä, L. Digital Media Institute Tampere University of Technology Tampere Finland Electronic System Design Department of Electronics The Royal Institute of Technology Kista Sweden Nokia Research Center Helsinki Finland

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Spatial evolutionary spectrum for DOA estimation and blind signal separation

Proceedings of SPIE - The International Society for Optical ...

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Proceedings of SPIE - The International Society for Optical Engineering 1999年 3807卷 480-490页

作者： Kayhan, A. Salim Amin, Moeness G.

关键词： Parallel processing systems

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Hardware implementation of a nonlinear processor

Hardware implementation of a nonlinear processor

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： v.K. Jain S. Shrivastava A.D. Snider D. Damerow D. Chester University of South Florida Tampa FL USA Harris Semiconductor Company Palm Bay FL USA

Several advanced DSP algorithms, arising in applications such as wireless communications, computer graphics, computerized tomography, and speech compression, require extensive use of nonlinear functions. We discuss a new hardware approach to high-speed computation of nonlinear functions. With this approach all of the functions needed can be regularized into a single efficient algorithm. Further, highly reduced cycle implementations can be achieved. Specifically, for real arguments, a new result can be produced every cycle-in a pipelined mode. The underlying principle which has made the combined goals of high-speed and multi-functionality possible is significance-based polynomial interpolation of very small ROM tables. Considered are the following seven functions: arctangent, cosine, logarithm, reciprocal, reciprocal-square-root, sine, and square-root. Also presented is a theoretical development for error prediction, a tool for the selection of architectural parameters. Finally, the paper presents a novel technique, named here as 'microshaping', for avoiding overflows, thereby eliminating exception handling.

关键词： Hardware Digital signal processing Application software Wireless communication Computer graphics Computed tomography Speech Polynomials Interpolation Read only memory

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Proceedings of SPIE: advanced signal processing algorithms, architectures, and implementations vIII

Proceedings of SPIE: Advanced signal processing algorithms, ...

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Advance signal processing algorithms, Atchitectures, and implementations vIII

The proceedings contains 58 papers from the conference of SPIE: advanced signal processing algorithms, architectures, and implementations vIII. The topics discussed include: blind channel identification and extraction of more sources than sensors;blind channel estimation for CDMA systems with orthogonal modulation;blind equalization and source separation with MSK inputs and adaptive blind channel estimation by least-squares smoothing for CDMA.

关键词： signal processing

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