基于简缩极化数据的三分量分解模型

基于部分极化波的二分理论,提出了一种针对简缩极化数据的三分量分解模型。该模型将简缩极化数据的Jones相干矩阵分解成表面散射、偶次散射和体散射三种散射机制Jones相干矩阵之和,进一步得到这三种散射机制各自的散射功率。选取德国根多夫市普拉特灵(Plattling)地区的TerraSAR-X全极化数据生成简缩极化数据,用提出的三分量分解模型对得到的简缩极化数据进行分解,并将分解结果与全极化数据的Pauli分解结果进行对比。实验结果表明:提出的简缩极化数据三分量分解模型能够很好地描述表面散射和体散射的散射行为。但是,相比全极化数据的分解结果,提出的模型高估了体散射分量,导致偶次散射分量偏小,这个问题需要进一步的研究来解决。     

A new compact model for external latchup

A model is presented for external latchup. The effects of spacing, temperature, supply voltage and layout are captured in the model. The model shows a good fit to measurement results from two different technologies, RF-CMOS and SmartMOS.     

A compact MOST model for design analysis

A dc model of the 4-terminal MOS transistor is described that eliminates the need for piecewise definition of the channel current while maintaining sufficient physical correspondence to accurately represent modern MOS devices used in arrays. The determination of model parameters is straightforward.     

A compact scattering model for the nanoscale double-gate MOSFET

An analytically compact model for the nanoscale double gate metal-oxide semiconductor field effect transistor (MOSFET) based on McKelvey's flux theory is developed. The model is continuous above and below threshold and from the linear to saturation regions. Most importantly, it describes nanoscale MOSFETs from the diffusive to ballistic regimes. In addition to its use in exploring the limits and circuit applications of double gate MOSFETs, the model also serves as an example of how semiclassical scattering theory can be used to develop physically sound models for nanoscale transistors     

Oxide thickness dependent compact model of channel noise for E-mode AlGaN/GaN MOS-HEMT

In this paper, a compact channel noise model for gate recessed enhancement mode GaN based MOS-HEMT which is valid for all regions of operation is proposed. The compact noise model consists of high frequency thermal noise and low frequency flicker noise. The drain current, which is one of the most important parameters for compact noise model is developed by incorporating interface and oxide traps, mobility degradation due to vertical electric field, velocity saturation effect and self-heating effect. The flicker noise model is derived by considering mobility and carrier fluctuation due to traps present in both oxide and interface layer. The thermal noise and flicker noise models are validated by comparing the results with TCAD simulation and experimental results from literature respectively. Effect of thermal and flicker noise power spectral density (PSD) variation with different oxide thickness has also been analyzed.     

A multipath model for the powerline channel

The development of powerline communication (PLC) systems for Internet, voice, and data services requires measurement-based models of the transfer characteristics of the mains network suitable for performance analysis by simulation. This paper presents an analytic model describing complex transfer functions of typical powerline networks using only a small set of parameters. The model is based on physical signal propagation effects in mains networks including numerous branches and impedance mismatching. Besides multipath propagation accompanied by frequency-selective fading, signal attenuation of typical power cables increasing with length and frequency is considered. A verification of the model at a test network, as well as its use for definition of attenuation profiles and reference channels, demonstrate the practical value of the proposed model     

基于短波测量数据的信道模型聚类方法

提出了一种使用减法聚类有效分类离散随机信道参数的方法．在青岛北京链路的信道测量数据基础上,使用该方法将短波信道测量计算出的信道参数分别进行一维和多维聚合分类,得到在特定链路、时间上,某频率对应的典型信道参数和信道模型,为短波频谱管理中的频率打分提供精确量化依据．     

蜂窝移动通信中一种分级紧致的动态信道分配方案

本文提出一种分级紧致的动态信道分配（CCDCA）方案。文中首先根据信道使用情况与业务量的关系，将小区分成“冷态”和“热态”，并给出了相应的阈值，然后在对“热态”的处理过程中利用“冷态”的先验信息，对不同状态的小区给出了不同的紧致措施。该方案还能保证小区间有较小的服务偏差，提高了整个系统的服务质量。文中还根据冷、热态的特点构造了一个二维马尔科夫链模型，计算出了模型的主要参数；其思想可用于分析多种信道分配问题。仿真结果证明CCDCA方案有较小的呼阻率和较高的频谱利用率。     

Evaluation of a data communication model for switched fibre channel

The ANSI standard fibre channel is emerging as the networking protocol of choice for high bandwidth applications. Fibre channel is an enabling technology because of the tremendous advantages in speed and latency it provides over existing networking technologies. Applications that weren't feasible before are now possible, and more applications that demand similar performance will follow. Fibre channel is the high performance alternative to existing networking technologies such as FDDI, Fast Ethernet, and ATM. Fibre channel (FC) provides for two different data communication models: connection (class 1 service) and connectionless (class 2 or 3 service). Although interoperable, some of these implementations may not result in optimal performance. There is some disagreement in the FC community as to which is more appropriate. Both have their advantages and disadvantages, and so it's necessary to look at each application individually. The article addresses some of these issues by simulating these two communication models over different switch architectures     

A video error concealment method using data hiding based on compressed sensing over lossy channel

The video error concealment with data hiding (VECDH) method aims to conceal video errors due to transmission according to the auxiliary data directly extracted from the received video file. It has the property that can well reduce the error propagated between spatially/temporally correlated macro-blocks. It is required that, the embedded information at the sender side should well capture/reflect the video characteristics. Moreover, the retrieved data should be capable of correcting video errors. The existing VECDH algorithms often embed the required information into the corresponding video frames to gain the transparency. However, at the receiver side, the reconstruction process may loss important information, which could result in a seriously distorted video. To improve the concealment performance, we propose an efficient VECDH algorithm based on compressed sensing (CS) in this paper. For the proposed method, the frame features to be embedded in every video frame are generated from the frame residuals CS measurements and scrambled with other frame features as marked data. The marked data is embedded into the corresponding frames by modulating color-triples for its least impacts on the carriers. For the receiver, the extracted data is used to reconstruct residuals to conceal errors. Error positions are located using the set theory. Since the CS has the ability to sample a signal within a lower sampling rate than the Shannon–Nyquist rate, the original signal could be reconstructed very well in theory. This indicates that the proposed method could benefit from the CS, and therefore keep better error concealment behavior. The experimental results show that the PSNR values gain about 10 dB averagely and the proposed scheme in this paper improves the video quality significantly comparing with the exiting VECDH schemes.     

A compact model of MOSFET mismatch for circuit design

This paper presents a compact model for MOS transistor mismatch. The mismatch model uses the carrier number fluctuation theory to account for the effects of local doping fluctuations along with an accurate and compact dc MOSFET model. The resulting matching model is valid for any operation condition, from weak to strong inversion, from the linear to the saturation region, and allows the assessment of mismatch from process and geometric parameters. Experimental results from a set of transistors integrated on a 0.35 /spl mu/m technology confirm the accuracy of our mismatch model under various bias conditions.     

Results of channel error profiles for DECT

This letter presents the main statistical characterization of the underlying error process obtained in the case of the Digital European Cordless Telecommunications (DECT) radio system. By simulation of the transmission Link, error sequences are generated for different channel parameters. Relevant statistics are then computed for the purpose of efficient channel coding design and evaluation     

A statistical model for the factory radio channel

A statistical model, based on experimental data, is presented to characterize the multipath propagation medium in typical manufacturing environments. The statistical behavior of the medium is described by a time-varying impulse response which includes the distribution of the parameters of the channel such as the gain, the interarrival time, and the number of paths. The resolvable components in a number of experimentally measured pulse responses of indoor factory radio channels were used to estimate the channel statistics. The interarrival times of the signals were modeled by the Weibull distribution. A model for the distribution of signals was presented using the modified beta distribution. The path gain coefficients were represented using the Rayleigh, Rician, or log-normal distributions. The model for the factory channel is flexible enough to fit the data for other indoor sites by changing the parameters of the factory channel appropriately relative to the size, topography, and other structural features of the site     

A Markov model for the mobile propagation channel

A finite-state Markov model is fitted to the mobile propagation channel by the use of contingency tables. Narrow-band Rayleigh and Ricean fading are considered in detail, but the techniques extend to other types of fading. Several criteria may indicate that a first-order finite-state Markov model sufficiently characterizes the channel behavior. The parameters of the model are obtained both from theoretical analysis and simulation. Functional dependence between the transition probabilities and the steady-state probabilities is found in the slow fading case     

Comments on `A compact thermal noise model for the investigation ofsoft error rates in MOS VLSI digital circuits'

For the original article see ibid., vol.24, no.1, p.78-89 (1989). In the above-title paper by P.D. Layman and S.G. Chamberlain, the mean-square noise voltage of a MOSFET transistor was determined in the frequency range Δf=2.2/(2πt_sen)=0.35(1/t _sen), whereas the mean-square value (and consequently the RMS) of thermal noise in the RC circuit was determined over an infinite frequency range. The commenter examines the implications of this approach to draw attention to a few questions that can significantly influence the accuracy of results in the course of consideration of noise in electronic circuits     

A unified short-channel compact model for cylindrical surrounding-gate MOSFET

For the first time, a continuous and explicit model valid in all operating regions, for undoped short-channel cylindrical gate-all-around (GAA) MOSFETs, is presented in this study. From a two-dimensional analysis, the threshold voltage roll-off, the drain-induced barrier lowering (DIBL) and the subthreshold swing are explicitly modeled. Short-channel effects are then implemented into a continuous drain-current model based on an effective surface potential approach using the gradual channel approximation. Improving the model behavior in the saturation operating region by accounting the channel pinch-off displacement, channel length modulation is studied and implemented as well. Analytical results are compared to TCAD-Atlas numerical simulations and validate the short-channel model in all operating modes making it suitable for circuit design simulations.     

A compact model for SiGe HBT on thin-film SOI

Heterojunction bipolar transistor (HBT) fabrication on thin-film silicon-on-insulator (SOI) has been recently demonstrated. Due to the space volume constraint (thin film) for the device fabrication, the HBT structure is different from bulk HBT. In fact, compared to a bulk device, the buried layer has been suppressed and a lateral collector contact configuration is introduced. This device features a vertical expansion followed by a lateral expansion of the base-collector space charge region. This nonconventional charge behavior induces a kink in the base-collector junction capacitance characteristics, and as a consequence a modified Early effect. Furthermore, the low current transit time is modified compared to a bulk HBT. In this paper, all these effects are analyzed and a compact model for SOI-HBT is proposed. The model is validated on real SOI-HBTs with different collector doping levels.     

A compact physical via blockage model

Via blockage due to signal interconnects and its impact on wirability of multi-billion-transistor chips are systematically analyzed. Via classifications are introduced. By taking advantage of a stochastic interconnect length distribution and a multi-level interconnect network architecture, a physical via blockage model exploiting channel availability is proposed. This model reveals that the most severe via blockage occurs on first metal level, wasting more than 10% and up to about 50% of wiring area. A new perspective on chip size limit imposed by via blockage is also provided by using the proposed model     

A minimum mean-squared error relay for the two-way relay channel with network coding

In this letter, we consider the two-way relay channel (TWRC) employing network coding. In TWRC, a conventional relay first decodes symbols from each user and combines (network coding) them using, for example, the XOR (eXclusive OR) operation. However, it may be suboptimal for the relay to use this concatenated approach, when the channels are noisy and the cost criterion is source distortion. Instead, we propose a new relay scheme that generates network coded symbols by performing symbol estimation and network coding operation jointly, in order to minimize the source distortion at the users.     

A measurement system for ultrawide-band communication channel characterization

In this paper a novel wide-band propagation channel measurement system with high dynamic range and sensitivity is introduced. The system enables the user to characterize signal propagation through a medium over a very wide frequency band with fine spectral resolution (as low as 3 Hz) by measuring the attenuation and phase characteristics of the medium. This system also allows for the study of temporal, spectral and spatial decorrelation. The high fidelity data gathered with this system can also be utilized to develop empirical models or used as a validation tool for physics based propagation models which simulate the behavior of radio waves in different environments such as forests, urban areas or indoor environments. The mobility and flexibility of the system allows for site specific measurements in various propagation scenarios.