串行通信服务器中的自适应以太网设计

串行通信服务器中的自适应快速以太网,其硬件包括运行操作系统及应用程序的MPC860T主处理器电路及其外围电路.快速以太网接口电路,负责以太网数据的收发.串行通道电路又分,负责配置监控服务器的SMC接口和负责4个HDLC数据收发功能电路.4个HDLC通道提供符合RS-232C和RS-422标准的接口.     

METHOD FOR ALONG-TRACK DUAL-ANTENNA AIRBORNE RADAR’S GMTI WHEN THE ATENNA ERROR CHANGES PULSE TO PULSE

This paper presents a joint method of Doppler Beam Sharpen (DBS) imaging and Signal Subspace Processing (SSP) to achieve Ground Moving Target Indication(GMTI) for alongtrack dual-antenna airborne radar. When the error of the two antennas (also refers to channels) changes pulse to pulse, the method SSP is used to precisely calibrate the two antennas‘ DBS images, then to detect the ground moving targets in the difference image of the two calibrated images. The method DBS-SSP is proved to offer performance improvement on the actually measured data and simulated data.     

MC-CDMA with exponential power profile in Nakagami fading channel

A refined study of multi-carrier code division multiple access transmission over a Nakagami fading channel is proposed. The channel power is modeled with an exponential power profile rather than the uniform profile prevalent in other papers. An expression for the bit error rate (BER) is then derived. Numerical results show that MC-CDMA performances depend on the power dispersion of interferers around the desired user power.     

Ad Hoc网络技术研究进展

AdHoc网络现在是非常有吸引力的研究方向。本文介绍了Ad Hoc网络的定义、特点、体系结构、信道接入协议，最后分析了Ad Hoc网络面临的问题。希望本文能为进行AdHoc网络技术研究的人们提供一定的方便。     

一种加权均方误差最小化的鲁棒性干扰对齐算法

线性干扰对齐的一个常见优化目标是总传输速率最大化,但因为和速率函数的非凸特性而难以直接求解。加权均方误差最小化算法借助均方误差与和速率之间的等价关系解决了这一问题。这一方法需要获得准确的信道状态信息,在实际应用中,通道估计误差的存在会导致算法性能的下降。该文提出一种改进算法,在干扰对齐预编码矩阵与接收矩阵的优化求解过程中将通道估计误差的统计特性考虑在内。仿真结果表明,相比以往的加权均方误差最小化算法,该文算法对信道估计误差具有较高的鲁棒性,可以有效提高总的传输速率。     

Iterative receiver for OFDM systems based on semi-blind channel estimation

In this paper we propose two iterative algorithms of joint channel estimation and symbol detection for Orthogonal Frequency Division Multiplexing （OFDM） systems. In which, superimposed pilot scheme is adopted and an initial Channel State Information （CSI） is obtained by employing a first-order statistic. In each subsequent iteration, we propose two algorithms to update the CSI. The Mean Square Error （MSE） of channel estimation and Bit Error Rate （BER） performance are given and simulation results demonstrate that the iterative algorithm using method B has good performance approaching the ideal condition.     

NC—2T系列机芯加装KAIDA系列遥控频道转换噪声及消除方法

本文分析了彩色ＮＣ－２Ｔ系列机芯加装ＫＡＩＤＡ系列遥控功能后产生频道转换品噪声的原因及消除方法。     

Channel length influenced contribution of hole and electron trapping effect to threshold voltage stability in organic field effect transistors

Effect of channel length on hysteresis and threshold voltage shift in copper phthalocyanine (CuPc) based organic field effect transistors was studied. Contrary to expectation, longer channel length devices exhibited minimum threshold voltage shift. Influence of channel length on the contribution of hole and electron trapping to threshold voltage stability was determined. Shortest channel length devices exhibited highest electron trapping effect while longest channel devices exhibited minimum hole as well as electron trapping. Lower hole trap effect for longer channel length devices was suggested to be due to reduced longitudinal field between source and drain electrodes while minimum electron trapping was attributed to suppression of drain current by increased hole trap centres.     

Performance Analysis of a Novel Cooperative Diversity Scheme

The traditional cooperative diversity could improve the system performance enormously, which has already widely been investigated by researchers. How-ever, it didn＇t exploit channel code and Distributed space-time block code （DSTBC） together to achieve both diversity gain and coding gain. Therefore, in order to further improve system performance, a novel cooperative diver-sity scheme based on concatenating the channel code and DSTBC is proposed in this paper. The closed-form expres-sions of channel capacity, outage probability and Bit error rate （BER） are derived to evaluate the performance of the proposed scheme. Also, computer simulations are conducted to validate our scheme, showing that, even though the interuser channel is noisy, the proposed scheme out-performs the traditional cooperative diversity in terms of channel capacity, outage probability and BER with distinct system gains.     

稀疏码分多址系统一种改进的检测算法

稀疏码分多址(SCMA)系统中基于球形译码算法(SD)由于具有优良的性能受到越来越多的关注,然而现有基于SD的算法只能用于某些特定星座结构的检测,导致其应用受限.该文提出一种适用于任意星座且性能达到最大似然(ML)算法性能的改进球形译码(ISD)算法.该算法将用户星座图拆分,并将用户星座图转换为多层树结构,利用对树结构...