共查询到20条相似文献,搜索用时 203 毫秒
1.
Jeffrey M. Arnold 《The Journal of VLSI Signal Processing》2007,47(1):3-14
A software configurable processor (SCP) is a hybrid device that couples a conventional processor datapath with programmable
logic to allow application programs to dynamically customize the instruction set. SCP architectures can offer significant
performance gains by exploiting data parallelism, operator specialization and deep pipelines. The S5000 is a family of high
performance software configurable processors for embedded applications. The S5000 consists of a conventional 32-bit RISC processor
coupled with a programmable Instruction Set Extension Fabric (ISEF). To develop an application for the S5 the programmer identifies
critical sections to be accelerated, writes one or more extension instructions as functions in a variant of the C programming
language, and accesses those functions from the application program. Performance gains of more than an order of magnitude
over the unaccelerated processor can be achieved.
相似文献
Jeffrey M. ArnoldEmail: |
2.
Based on orthogonal designs, space-time (ST) block codes that enable full diversity as well as a simple maximum likelihood
(ML) decoding algorithm at the decoder can be constructed for more than two transmit antennas. For real constellations (such
as PAM), ST block codes with transmission rate 1 can be designed from the real Hurwitz-Radon families for any number of transmit
antennas. However, for complex constellations (such as M-PSK or M-QAM), ST block codes for more than two transmit antennas
can only be constructed with rates less than 1. Previous attempts have been concentrated on complex orthogonal designs that
provide ST block codes with full diversity and high transmission rates. In this paper, we present two rate 2/3 complex ST
block codes from orthogonal designs for five and six transmit antennas, respectively. Simulation results are provided to demonstrate
the significant performance gains made by the proposed ST block codes.
相似文献
Yi GongEmail: |
3.
This paper discusses an automated method to divide scan chains into multiple scan segments that are suitable for power-constrained
at-speed testing using the skewed-load test application strategy. By dividing a circuit into multiple partitions, which can
be tested independently, both power during shift and power during capture can be controlled. Despite activating one partition
at a time, we show how through conscious construction of scan segments, high transition fault coverage can be achieved, while
reducing test time of the circuit and employing third party test generation tools.
相似文献
Nicola NicoliciEmail: |
4.
Stephan Sand Christian Mensing Carlo Mutti Armin Wittneben 《Wireless Personal Communications》2008,47(1):51-61
In this paper, we consider a transmission system employing orthogonal frequency division multiplexing with bit-interleaved
coded modulation and perfect channel state information at both transmitter and receiver. An adaptive bit loading scheme in
combination with cyclic delay diversity and discontinuous Doppler diversity is proposed at the transmitter and iterative demapping
and decoding at the receiver. The loading procedure minimizes the bit-error rate at the decoder output, and the transmit diversity
schemes mitigate channel correlations. We analyze the iterative receiver with extrinsic information transfer charts and present
the achievable gains.
相似文献
Armin WittnebenEmail: |
5.
This paper presents an Application Specific Instruction Set Processor (ASIP) for implementation of H.264/AVC, called Video
Specific Instruction-set Processor (VSIP). The proposed VSIP has novel instructions and optimized hardware architectures for
specific applications, such as intra prediction, in-loop deblocking filter, integer transform, etc. Moreover, VSIP has coprocessors
for computation intensive parts in video signal processing, such as inter prediction and entropy coding. The proposed VSIP
has much smaller area and can dramatically reduce the number of memory access compared with commercial DSP chips, which result
in low power consumption. Moreover, the proposed hardware accelerators have small size, consume low power consumption, and
thus, they can support real-time video processing. VSIP has been thoroughly verified using an FPGA board having the Xilinx™
Virtex II. VSIP can implement a real-time H.264/AVC decoder. The proposed VSIP is one of promising solutions for video signal
processing.
相似文献
Sung Dae KimEmail: |
6.
Mari Carmen Aguayo-Torres José Tomás Entrambasaguas Muñoz Javier Poncela Gerardo Gómez 《Wireless Personal Communications》2009,49(3):321-334
Path to Global Information Multimedia Communication Village (GIMCV) can be seen as a convergence process among telephony,
data exchange and television. Convergence refers not only to various services provided by the same operator but also by the
same device, the same access network, the same transport network, etc. This paper present authors’ vision on how convergence
will lead the GIMCV development.
相似文献
Mari Carmen Aguayo-TorresEmail: |
7.
Since high-quality image/video systems based on the JPEG/MPEG compression standards often require power-expensive implementations
at relatively high bit-rates, they have not been widely used in low-power wireless applications. To alleviate this problem,
we designed, implemented, and evaluated a strategy that can adapt to different compression and transmission rates. (1) It
gives important parts of an image higher priority over unimportant parts. Therefore, the high-priority parts can achieve high
image quality, while the low-priority parts, with a slight sacrifice of quality, can achieve huge compression rate and thus
save the power/energy of a low-power wireless system. (2) We also introduce a priority-driven scheduling approach into our
coding algorithm, which makes the transmission of important parts earlier with more data than other parts. Through a balanced
trade-off between the available time/bandwidth/power and the image quality, this adaptive strategy can satisfy users with
desired images quality and lead to a significant reduction of the important parts’ deadline misses.
相似文献
Feng Shang (Corresponding author)Email: |
8.
For applications requiring a large dynamic, real numbers may be represented either in floating-point, or in the logarithm
number system (LNS). Which system is best for a given application is difficult to know in advance, because the cost and performance
of LNS operators depend on the target accuracy in a highly non linear way. Therefore, a comparison of the pros and cons of
both number systems in terms of cost, performance and overall accuracy is only relevant on a per-application basis. To make
such a comparison possible, two concurrent libraries of parameterized arithmetic operators, targeting recent field-programmable
gate arrays, are presented. They are unbiased in the sense that they strive to reflect the state-of-the-art for both number
systems. These libraries are freely available at .
相似文献
Jérémie Detrey (Corresponding author)Email: |
Florent de DinechinEmail: |
9.
Expressions are given for the moment generating functions of the Rayleigh and generalized Rayleigh distributions.
相似文献
Saralees NadarajahEmail: |
10.
In this article, we study an asynchronous optical packet switch equipped with a number of wavelength converters shared per
node. The wavelength converters can be full range or circular-type limited range. We use the algorithmic methods devised for
Markov chains of block-tridiagonal type in addition to fixed-point iterations to approximately solve this relatively complex
system. In our approach, we also take into account the finite number of fiber interfaces using the Engset traffic model rather
than the usual Poisson traffic modeling. The proposed analytical method provides an accurate approximation for full range
systems for relatively large number of interfaces and for circular-type limited range wavelength conversion systems for which
the tuning range is relatively narrow.
相似文献
Carla RaffaelliEmail: |
11.
Dana Brown John Ferrario Randy Wolf Jing Li Jayendra Bhagat Mustapha Slamani 《Journal of Electronic Testing》2007,23(1):85-94
In this paper, testing of radio frequency (RF) devices with mixed-signal testers is discussed. General purpose automatic test
equipment (ATE) will be used. In this paper, a more universal test structure utilizing RF building blocks is proposed. A global
positioning system (GPS) device is used as an example to illustrate how to develop the RF test plan with this usage. The test
plan developed includes fast, cost-effective and dedicated circuitry.
相似文献
Jing LiEmail: |
12.
Paolo Costa Geoff Coulson Cecilia Mascolo Luca Mottola Gian Pietro Picco Stefanos Zachariadis 《International Journal of Wireless Information Networks》2007,14(2):149-162
Next generation embedded systems will be composed of large numbers of heterogeneous devices. These will typically be resource-constrained
(such as sensor motes), will use different operating systems, and will be connected through different types of network interfaces.
Additionally, they may be mobile and/or form ad-hoc networks with their peers, and will need to be adaptive to changing conditions
based on context-awareness. Our focus in this paper is on the provision of a middleware framework for such system environments.
Our approach is based on a small and efficient ‘middleware kernel’ which supports highly modularised and customisable component-based
middleware services that can be tailored for specific embedded environments, and are runtime reconfigurable to support adaptivity.
These services are primarily communications-related but also address a range of other concerns including service discovery
and logical mobility. In the paper we provide an overview of our approach, focusing in detail on both the middleware kernel
and the services. We also discuss an application scenario in which we are currently applying and evaluating our middleware
approach.
相似文献
Stefanos ZachariadisEmail: |
13.
A Survey of Cryptographic Primitives and Implementations for Hardware-Constrained Sensor Network Nodes 总被引:1,自引:0,他引:1
In a wireless sensor network environment, a sensor node is extremely constrained in terms of hardware due to factors such
as maximizing lifetime and minimizing physical size and overall cost. Nevertheless, these nodes must be able to run cryptographic
operations based on primitives such as hash functions, symmetric encryption and public key cryptography in order to allow
the creation of secure services. Our objective in this paper is to survey how the existing research-based and commercial-based
sensor nodes are suitable for this purpose, analyzing how the hardware can influence the provision of the primitives and how
software implementations tackles the task of implementing instances of those primitives. As a result, it will be possible
to evaluate the influence of provision of security in the protocols and applications/scenarios where sensors can be used.
相似文献
Javier LopezEmail: |
14.
Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) transmission can improve both the transmission
capacity and performance due to diversity gain. However, when the antennas are close to each other in a MIMO-OFDM system,
the diversity order will be decreased because of channel correlation. In the paper performance of various detection methods
for space–time block code (STBC) MIMO-OFDM with channel correlation are evaluated, including the conventional Alamouti full
matrix detection, the modified diagonal matrix detection, the least square-zero forcing (LS-ZF) detection, and the successive
interference cancellation (SIC). The paper also verify that the SIC detection can still keep excellent detection performance
under large channel correlation.
相似文献
Shyue-Win WeiEmail: |
15.
A New Routing Metric for Satisfying Both Energy and Delay Constraints in Wireless Sensor Networks 总被引:1,自引:0,他引:1
Besides energy constraint, wireless sensor networks should also be able to provide bounded communication delay when they are
used to support real-time applications. In this paper, a new routing metric is proposed. It takes into account both energy
and delay constraints. It can be used in AODV. By mathematical analysis and simulations, we have shown the efficiency of this
new routing metric.
相似文献
YeQiong SongEmail: |
16.
A. Pérez-Pascual T. Sansaloni V. Torres V. Almenar J. Valls 《Journal of Signal Processing Systems》2009,56(1):35-40
This paper shows that when a digital receiver is designed utilizing two clock scopes, the digital down-converter can be designed
to be efficient in terms of area and power consumption. The main design parameter that contributes to make the design efficient
is the relationship between the transition band of the designed filter and its sampling frequency.
相似文献
J. VallsEmail: |
17.
Saralees Nadarajah 《Wireless Personal Communications》2009,49(4):575-585
The quantization error for MIMO (multiple-input multiple-output) downlink channels is known to be the minimum of independent
and identically distributed beta random variables. In this note, an exact expression is derived for the average quantization
error. Computational issues relating to its correctness, usage and approximations are discussed.
相似文献
Saralees NadarajahEmail: |
18.
High-speed and low area hardware architectures of the Whirlpool hash function are presented in this paper. A full Look-up
Table (LUT) based design is shown to be the fastest method by which to implement the non-linear layer of the algorithm in
terms of logic. An unrolled Whirlpool architecture implemented on the Virtex XC4VLX100 device achieves a throughput of 4.9 Gbps.
This is faster than a SHA-512 design implemented on the same device and other previously reported hash function architectures.
A low area iterative architecture, which utilises 64-bit operations as opposed to full 512-bit operations, is also described.
It runs at 430 Mbps and occupies 709 slices on a Virtex X4VLX15. This proves to be one of the smallest 512-bit hash function
architectures currently available.
相似文献
Ciaran McIvorEmail: |
19.
Elliptic curve cryptography (ECC) is recognized as a fast cryptography system and has many applications in security systems.
In this paper, a novel sharing scheme is proposed to significantly reduce the number of field multiplications and the usage
of lookup tables, providing high speed operations for both hardware and software realizations.
相似文献
Brian KingEmail: |
20.
Marcio Juliato Guido Araujo Julio López Ricardo Dahab 《The Journal of VLSI Signal Processing》2007,47(1):59-76
This paper presents a comprehensive analysis of the design of custom instructions in a reconfigurable hardware platform dedicated
to accelerate arithmetic operations in the binary field , using a Gaussian normal basis representation. The resulting platform is capable of running real applications, thus allowing
a precise measurement of the execution overheads, and a fair comparison of the hardware and software speedups at several implementation
levels. By using this approach, we determine which field operations (e.g., multiplication) are better suited to constrained
environments, and which ones provide an enhanced performance in general-purpose systems. Experimental results reveal that
by using our fastest field multiplier implemented as a custom instruction in a combined hardware/software approach, we accelerate
point multiplication (the fundamental operation in Elliptic Curve Cryptography) over 126 times.
相似文献
Ricardo DahabEmail: |