We discuss a symbol-decomposition method that combines the descriptions of the resulting models to save model redundancy. The proposed method is based on weighting.
ISBN:
(纸本)0780371232
We discuss a symbol-decomposition method that combines the descriptions of the resulting models to save model redundancy. The proposed method is based on weighting.
In orthogonal frequency division multiple access -code division multiplexing (OFDMA-CDM), rate adaptation is known as one of the key techniques to improve the reliability of the transmission signal. However, since the...
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ISBN:
(纸本)9781424451227;9781424451234
In orthogonal frequency division multiple access -code division multiplexing (OFDMA-CDM), rate adaptation is known as one of the key techniques to improve the reliability of the transmission signal. However, since the one subchannel size in OFDMA-CDM depends on the spreading code length, the fading shift which the transmission signal receives per one subchannel might depend on the spreading code length. If the influence of the fading shift can be suppressed according to the multiplexing ratio, the effect of the rate adaptation can be improved. In addition, by allocating the subchannel with multiuser diversity in OFDMA, the effect of the rate adaptation can be more improved. We propose a subchannel allocation scheme based on the maximum, minimum and average signal to interference plus noise ratio (SINR) and orthogonal variable spreading factor (OVSF) code allocation to despread in narrowband according to the multiplexing ratio. We demonstrate that the proposed scheme can improve the bit error rate (BER) performance.
A software based hybrid test vector compression technique for testing system-on-chip integrated circuits using an embedded processor core was previously discussed by the authors. In this approach, a software program i...
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A software based hybrid test vector compression technique for testing system-on-chip integrated circuits using an embedded processor core was previously discussed by the authors. In this approach, a software program is loaded into the on-chip processor memory along with the compressed test data sets. To minimize on-chip storage besides testing time, the test data volume is first reduced by compaction in a hybrid manner before downloading into the processor. The proposed method utilizes a set of adaptive coding techniques for realizing lossless compression. The compaction program need not be loaded into the embedded processor, as only the decompression of test data is required for the automatic test equipment. The developed scheme necessitates minimal hardware overhead, while the on-chip embedded processor can be reused for normal operation on completion of testing. As an extension of this prior work, this paper reports further results on studies of the problem based on the use of Limpel-Ziv-Walsh coding besides Burrows-Wheeler transformation and demonstrates the feasibility of the suggested methodology with simulation results on ISCAS 85 combinational and ISCAS 89 full-scan sequential benchmark circuits.
Devices and associated applications are increasingly connected to a variety of smart modems that have dynamically varying link characteristics. For example, incoming and outgoing link rates can be varied over time wit...
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ISBN:
(纸本)9781457705564
Devices and associated applications are increasingly connected to a variety of smart modems that have dynamically varying link characteristics. For example, incoming and outgoing link rates can be varied over time with adaptive coding and modulation to suit the channel characteristics. In addition, those links may go up and down due to a variety of factors. The link rate and conditions offered by the modem to connected devices and associated applications therefore vary. In order to autonomously condition traffic and allow the network to get the most out of the modem's link capacity, the upstream devices and applications need to be informed of the modem's link conditions. This becomes a form of cognitive networking. This paper will discuss the problem and present a simple protocol that can be used to provide upstream devices and applications with downstream link conditions. While the protocol in this document is described in the context of modem radio-frequency link properties, it can also be broadly applied to other scenarios such as cryptographic devices.
The paper describes a new adaptive coding technique for still, grey-level images. The algorithm is based on a multi-resolution decomposition on biorthogonal wavelet basis and it includes different nonlinear models of ...
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The paper describes a new adaptive coding technique for still, grey-level images. The algorithm is based on a multi-resolution decomposition on biorthogonal wavelet basis and it includes different nonlinear models of the human visual perception in the compression task. Quantization is adaptive, and it is based on considerations about the contrast experiments which aim at determining in which conditions (contrast of the input image, compression ratio) the inclusion of the models improves the performance. The results are compared with standard techniques which do not include considerations about human visual perception.
Delivering video over the Web has posted a big problem. Video files are extremely big and need hours or even tens of hours to download. The available bandwidth varies dynamically. The conventional proactive buffering ...
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ISBN:
(纸本)9780769521008
Delivering video over the Web has posted a big problem. Video files are extremely big and need hours or even tens of hours to download. The available bandwidth varies dynamically. The conventional proactive buffering approach used by current video players cannot fully satisfy user needs. This paper presents a system designed to allow efficient retrieving, browsing and real-time playing of videos through the Internet using a web browser. The scheme is domain-specific.
This paper suggests a new adaptive length FEC algorithm to satisfy various line rates for metropolitan 32 ch × 10 Gb/s DWDM systems. With using FEC, the receiver sensitivity of transmission over 100 km of standar...
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This paper suggests a new adaptive length FEC algorithm to satisfy various line rates for metropolitan 32 ch × 10 Gb/s DWDM systems. With using FEC, the receiver sensitivity of transmission over 100 km of standard SMF for uncompensated conditions is improved by 1 dB with respect to 0 km at 10 -12 BER.
The author demonstrates an adaptive rate coding system based on the majority logic decoding of convolutional codes. The proposed system retains the high-data-rate capability of FEC (forward error correction) majority ...
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The author demonstrates an adaptive rate coding system based on the majority logic decoding of convolutional codes. The proposed system retains the high-data-rate capability of FEC (forward error correction) majority logic decoders while providing an adaptive code rate and a significant improvement in error protection through the incorporation of diversity combining and hybrid-ARQ (automatic repeat request) techniques. It is shown through analysis and simulation that this error control system provides a high level of data reliability at the expense of a minimal reduction in throughput.< >
Channel prediction is the key requirement in adaptive transmission techniques such as adaptive modulation, adaptive coding and adaptive power control. The paper presents a novel self organizing map (SOM) based channel...
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Channel prediction is the key requirement in adaptive transmission techniques such as adaptive modulation, adaptive coding and adaptive power control. The paper presents a novel self organizing map (SOM) based channel predictor for the downlink of an orthogonal frequency-division multiple access (OFDMA) system. The proposed predictor uses a Kalman trained-SOM backed mixtures of experts (ME) modular neural network. The performance of the predictor is evaluated on an OFDMA system with a system delay where channel prediction is needed.
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