The design of complex modern embedded systems like wireless communication systems becomes increasingly inefficient. The methods used in the design process ranging from system concept design to hardware and/or software...
详细信息
The design of complex modern embedded systems like wireless communication systems becomes increasingly inefficient. The methods used in the design process ranging from system concept design to hardware and/or software implementation are diverse, and typically managed by different teams with quite different expertise in a company. This naturally leads to communication problems between the teams. In this paper we highlight a new concept on hardware-oriented signalprocessing in education, where the same group of students passes through the whole design process. We describe a tripartite coordinated course series consisting of a lecture, a concept and simulation oriented exercise course using MATLAB and a practical course, where finally real hardware is developed using FPGAs (Field Programmable Gate Arrays).
We consider several array signalprocessing architectures equipped with different training approaches and evaluate their performance in high-speed digital wireless transmission by way of computer simulation. The array...
详细信息
We consider several array signalprocessing architectures equipped with different training approaches and evaluate their performance in high-speed digital wireless transmission by way of computer simulation. The array architectures considered are: space-only, delay-combine, and multi-stage space-time. The training approaches considered include max-SINR, LS (least-squares) with channel estimation, and LS without channel estimation. These arrays are simpler than the full space-time architecture at the cost of a lower error-rate performance.
Internet telephony is anticipated to grow into a major system for voice communication, even more so when it is extended to support wireless and mobile users. This last step is however not straightforward since the ins...
详细信息
Internet telephony is anticipated to grow into a major system for voice communication, even more so when it is extended to support wireless and mobile users. This last step is however not straightforward since the insertion of a wireless link generates distinctly new impairments like fading, noise and corruption and loss of packets at the MAC (medium access control) layer. Different techniques to mitigate these voice stream disruptions exist, but they are not directly extendible towards the wireless Internet telephony scenario. We have investigated several of these techniques and focussed on the necessary changes. Our simulations show that a new buffering scheme is needed at the receiver and that several tradeoffs in other parts of the system arise therefrom. This apparent interaction between the different techniques requires a global optimization. Moreover, we show that the optimal settings depend heavily on the wireless load and channel conditions such that the system must be designed to exhibit on-the-fly adaptation capabilities.
A technique is described for partitioning 2-D signal flow graph (SFG)/systolic arrays to a 2-D triangular array (triarray) of N(N+1)/2 processors. The folding technique can be used to partition 2-D SFGs onto smaller s...
详细信息
A technique is described for partitioning 2-D signal flow graph (SFG)/systolic arrays to a 2-D triangular array (triarray) of N(N+1)/2 processors. The folding technique can be used to partition 2-D SFGs onto smaller subarrays of the SFG. The stages of development are all highly suited to CAD from algorithm specification to array implementation, and can be performed in an integrated mapping methodology using the Occam algebra. Because of the Occam algebra-based partitioning, the data flow of the SFG has been preserved and the SFG implementation on the triarray is guaranteed to be functionally correct. The control overheads introduced by this scheme are minimal and very straightforward, i.e. a very simple mux and demux processes at the link interfaces of each transputer to code and decode the data flow tags. It is concluded that a triarray of transputers (or transputer link wavefront devices) is a highly versatile and flexible array processor when the folding scheme is used.< >
This paper presents a wide class of signal processing algorithms which employs a nonlinear operation in the time domain and is capable of providing good power/bandwidth tradeoffs with OFDM transmission. A suitable ana...
详细信息
This paper presents a wide class of signal processing algorithms which employs a nonlinear operation in the time domain and is capable of providing good power/bandwidth tradeoffs with OFDM transmission. A suitable analytical approach is proposed for efficiently evaluating the performance within this class of algorithms, and several performance results are shown and discussed in detail.
The most popular Moore's law formulation, which states the number of transistors on integrated circuits doubles every 18 months, is said to hold for at least another two decades. According to this prediction, if w...
详细信息
The most popular Moore's law formulation, which states the number of transistors on integrated circuits doubles every 18 months, is said to hold for at least another two decades. According to this prediction, if we want to take advantage of technological evolutions, designer's productivity has to increase in the same proportions. To take up this challenge, system level design solutions have been set up, but many efforts have still to be done on system modelling and synthesis. In this paper we propose a computation core synthesis methodology that can be integrated on the communication refinement steps of electronic system level design tools. In the proposed approach, computation cores used for digital signalprocessing application specifications relying on coarse grain communications and synchronizations (e.g. matrix) can be refined into computation cores which can handle fine grain communications and synchronizations (e.g. scalar). Its originality is its ability to synthesize computation cores which can handle fine grain data consumptions and productions which respect the intrinsic partial orders of the algorithms while preserving their original functionalities. Such cores can be used to model fine grain input output overlapping or iteration pipelining. Our flow is based on the analysis of a fine grain signal flow graph used to extract fine grain synchronizations and algorithmic expressions
A methodology for the analysis of the structure of a given digital signalprocessing algorithm is presented. The task precedence relationships within a scheduling cycle are derived for scheduling cycles that contain o...
详细信息
A methodology for the analysis of the structure of a given digital signalprocessing algorithm is presented. The task precedence relationships within a scheduling cycle are derived for scheduling cycles that contain one and two basic cycles, which is sufficient to derive the precedence relationships for scheduling cycles that contain an arbitrary number of basic cycles. The schedules considered are deterministic and non-preemptive for multiprocessor parallel environments with a variable number of processing elements. The complexity algorithm is analyzed, and its application to the development of digital signalprocessing software for systems which impose an execution speed constraint is discussed.< >
This paper considers the problem of source localization High resolution methods. These techniques are used in various domains of physics such as the underwater acoustics (sonar), and electromagnetic (radar), but also ...
详细信息
This paper considers the problem of source localization High resolution methods. These techniques are used in various domains of physics such as the underwater acoustics (sonar), and electromagnetic (radar), but also in other areas such as telecommunications, geophysics, seismic, biomedical, medical imaging, and radio astronomy, where it is often necessary to locate several sources (active or passive) at the same time, with very good resolution, in order to separate them even when they are very close. In the conventional high-resolution array processing, source localization is performed by means of the inversion of the spectral matrix between sensors, inversion can be difficult when the separation between the sources of interest and noisemakers is not clear. We propose original methods for locating sources which, by means of a suitable decomposition, prevent the inversion of the spectral matrix. These methods are on the triangular factorization of the spectral matrix product of two matrices (LU in one case and QR in the other). The essential property of these matrices U and R that the information on the energies are better organized than in the spectral matrix. Furthermore, this technique allows better dynamics to estimate the signal sources, that using the original spectral matrix. Furthermore, we propose two new estimators for source localization without knowing the number of sources a priori. The big advantage of these new estimators is to improve the localization in the presence of low signal to noise ratio (SNR). The performances of these estimators are comparable to that of the Multiple signal Classification (MUSIC) algorithm which exhibit higher computational load and needs the knowledge of the number of sources. The new estimators decrease the computational complexity. Even if we use existing mathematical tools, this is the first time such an approach is proposed in array processing.
This paper presents two FM receiver architectures and three digital signal processing algorithms for enhancing the output audio quality of FM broadcast receivers. The two receiver architectures differ only in the fron...
详细信息
This paper presents two FM receiver architectures and three digital signal processing algorithms for enhancing the output audio quality of FM broadcast receivers. The two receiver architectures differ only in the front-end processing for estimating the carrier-to-noise ratio and noise floors of the stereo audio signals. The shared back-end processing consists of three algorithms to suppress the noise in the audio signal, to detect and cancel noise pulses (static), and to conceal the degrading effects of fast fading, respectively. Together these FM enhancement techniques achieve about 20 to 35 dB improvements in SNR and stereo separation over a wide range of RF signal strength spanning nearly 30 dB. Perceptually, the audio quality improvement is large and obvious when the received FM signal is weak.
MAT2DSP is a MATLAB toolbox, currently under development, whose function is to estimate the implementation requirements of algorithms specified in the form of a MATLAB program. This toolbox is aimed at providing resea...
详细信息
MAT2DSP is a MATLAB toolbox, currently under development, whose function is to estimate the implementation requirements of algorithms specified in the form of a MATLAB program. This toolbox is aimed at providing researchers developing advanced signal and image processingalgorithms, a quick and convenient way of estimating what would be needed to implement their algorithm on a specified processor; MAT2DSP analyzes the user program and generates reports on its computational requirements.
暂无评论