HSDPA部署策略及覆盖、容量规划

本文介绍了HSDPA的发展背景,针对HSDPA的主要技术特点,依据市场发展规划、用户需求等方面对HSDPA部署进行探讨,并对HSDPA的覆盖与容量方面进行规划分析.     

Improved aquila optimization-based parameter evaluation framework and meta-heuristic algorithm in radio-over-fiber SpatialMux multi-input multi-output long-term evolution system

In heterogeneous access network, Multiple-Input Multiple-Output (MIMO) radio-over-fiber (RoF) system is an efficient approach for multiple signal transmission with low cost and complexity. The performance of RoF fronthaul system in MIMO system will be varied with different nonlinear effects. By adjusting various transmission parameters, such as the input signal power or the laser bias current, the nonlinear impacts produced by the RoF system can be reduced. In this paper, a novel algorithm Improved Aquila Optimization (IAO) is proposed to optimize transmission circumstances of MIMO RoF system. It determines the appropriate bias current for both lasers and Radio Frequency (RF) signal power in a short period. The input signals are wavelength multiplexed with Intensity Modulation and Direct Detection (IM/DD) applied. The carrier as well as transmission frequency is governed by the MIMO-Long-Term Evolution (LTE) standard. The proposed system is implemented in MATLAB, and the performance is evaluated. The experimental results show that fast convergence and trade-off between noise and nonlinearity are obtained with varying bandwidth. In the experimental scenario, the maximum Error Vector Magnitude (EVM) of 1.88, 3.14, and signal-to-noise ratio (SNR) of 3.204, and 2.698 was attained for both quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) modulation. [Correction added on 24 April 2023, after first online publication: the SNR values were corrected in the preceding sentence.] For 100 iterations, the processing time was reduced to 0.137 s. When compared with the conventional state-of-the-art approaches, the accuracy and computational complexity of the proposed approach are improved.     

一种新的时变衰落信道下MIMO系统的功率分配与自适应调制算法

本文提出一种在时变衰落信道下,MIMO系统的功率分配和自适应调制方法.该方法采用空域注水定理,在发送端天线的平均功率受限的条件下,按照信道传输矩阵的奇异值对发端的多天线进行最优功率分配和自适应MQAM调制.本文从频谱效率方面对其性能进行分析.给出了信道估计的误差和反馈时延对该方法的影响.理论分析和仿真结果表明,该方法实现简单,且与传统的总功率受限的自适应调制方法相比,具有更高的频谱效率.     

Optimal design of a multi-mode interference splitter based on SOI

In this paper, the multimode waveguide lengths and the output port locations of a SOI （silicon on insulator） material-based 1×4 MMI （multimode interference） optical splitter are optimized by means of FD-BPM （finite difference - beam propagation method）. An improved 1×4 MMI optical splitter is designed. Compared with an usual optical splitter, a smaller loss 0. 12dB and a better output port power uniformity 0.11dB are achieved for the optical signal transmission.     

Novel components for tunable micro-optics

We will present some technologies and devices employed for the fabrication of tunable micro-optics. Tunable liquid lenses and lens arrays as well as polymer membrane-based microlenses and scanning mirrors are of both academic and industrial interest in this area.     

Raman amplification of Stokes pulse in ultra-small silicon-on-insulator optical waveguide

The stimulated Raman amplification of picosecond Stokes pulse is numerically investigated in ultra-small silicon-oninsulator optical waveguide. Numerical results show that we obtain the gain of up to 30-dB for weak Stokes pulse in the copropagation configuration for 10 mm Jength waveguide using high intensity pump oPtical pulse. The peak gain, purse width, rise time, and fall time of Stokes pulse will experience the variation course of decaying then increasing with increasing waveguide length. The time delay of output Stokes pulse is controlled by adjusting the initial time delay of both pump and Stokes pulses.     

基于MC9S12XET256MAL的汽车车身控制模块系统电路设计

本设计是以Freescale导体的MC9S12XET256MAL设计车载车身控制单元,主要实现功能包含车窗控制,车灯控制,背光控制,RKE,雨刮,清洗电机,防盗报警,中控门锁,行车喇叭,安全指示灯,CAN总线,LIN总线。增强汽车的安全、舒适和方便性。用户可以对外部按键操作实现相应功能,同时采集相关传感器自动实现相关功能,例如雨刮,防盗报警。利用总线将显示系统、驾驶员信息系统、导航系统、计算机网络系统、状态监测与故障诊断系统等连接。     

Near-infrared emission from PbS quantum dots in polymer matrix

PbS quantum dots were prepared in the aqueous medium from readily available precursors. The shape of the particles isapproximately spherical, and the average particle size observed from HRTEM image was 7-8 nm. We applied PbS quantumdots and PMMA polymer to fabricate PbS quantum dots-PMMA composites, and investigate the photoluminescence PbSquantum dots in PMMA matrix with different mass ratio. PbS quantum dots in PMMA matrix have broad emission be-tween 900 nm and 1 500 nm and photoluminescence peak at 1 179 nm. Additionally, the photoluminescence intensityincreases with increasing the dopant concentration. PbS quantum dots-PMMA polymer composites can be potentially usedfor polymer optical fiber and electroluminescence (EL) in optical communication.     

MIMO信号检测中软信息计算的简化方法

编码的多入多出（MIMO）迭代接收技术,是一种高频谱利用率、高性能的接收技术。本文对这种迭代接收机进行了分析。为便于硬件实现,利用QAM调制的特性,对MIMO信号检测中的软信息计算提出了简化方法。仿真结果表明,简化方法对系统性能影响很小。     

基于图像重组和比特置乱的多图像加密

针对现有多图像加密算法只能同时加密多张同类型同大小的图像,适用范围不广、实用性差等问题,提出一种基于图像重组和比特置乱的多图像加密算法.该算法通过将任意数量、不同大小和不同类型的图像重新组合成新多灰度图,一次完成同时加密,极大提高了加密效率和适用范围.首先,依次提取所有待加密图像像素值重新组合出N张m×n新灰度图,并将其转化成m×n×8N二进制矩阵.然后,采用3D比特置乱方式,对高位页进行行列比特置乱,低位页进行整页比特置乱.最后,进行异或扩散操作,得到密文图像.高低位分开置乱提高了算法的抗噪声能力,最终密文信息熵达到7.999以上,很好地掩盖了明文的统计特性.构造一种新型Logistic与广义三阶Fibonacci级联的混沌系统产生随机序列,增加了初值和控制参数范围,扩大了密钥空间,使其达到8×10^84以上,极大地提高了抗穷举攻击能力.既提高了序列随机性,又同时保留了低维混沌系统的快速性.结合明文哈希值(SHA-256)产生密钥,明文像素值发生微小改变后密文像素值变化率达到0.996以上,极大地提高了的明文敏感性和算法抗选择明文攻击的能力.实验分析表明,提出的多图像加密算法安全性高、实用性强.