Bio-inspired power control and channel allocation for cellular networks with D2D communications

With the tremendous increment of traffic in the next generation mobile networks, device to device (D2D) communication is proposed to relieve the traffic burden of the base station and improve the overall network capacity. It supports direct communications between devices and could reuse the resources of cellular users (CUs). Despite the advantages, D2D communications bring great challenges in interference management. In this paper, we study the power control and channel allocation problems in three scenarios: (1) one CU and one D2D pair; (2) one CU and multiple D2D pairs; (3) multiple CUs and multiple D2D pairs. The goal is to coordinate the mutual interferences and maximize the overall network capacity. We derive sufficient conditions to guarantee the efficiency of D2D communications in scenarios with one CU and one D2D pair. We propose the bio-inspired PSO-P power control algorithm for the scenarios with one CU and multiple D2D pairs, and the PSO-CP algorithm for the scenarios with multiple CUs and multiple D2D pairs to jointly assign channels and powers. Simulation results show that the proposed algorithms are efficient in improving the overall network capacity.

     

Fault-Tolerant Cooperative Spectrum Sensing Scheme for Cognitive Radio Networks

In order to solve the uncertainty resulting from shadowing effect and resist the attack from malicious cognitive radio (CR) users, we propose a fault-tolerant cooperative spectrum sensing scheme for CR networks, where an energy detection-based local spectrum sensing is performed at each CR user, a coefficient is used to weight each CR user’s sensing result, a linear weighted fusion process is performed at the fusion center (FC) to combine received sensing results. For a fault-tolerant cooperative spectrum sensing scheme, the most important issue is to distinguish whether the CR user is reliable or not. In this paper, a reputation-based cooperative mechanism is presented to alleviate the influence of the unreliable sensing results from CR users suffering shadowing and the false sensing data from malicious CR users on the detection result at the FC. In proposed fault-tolerant cooperative scheme, each cooperative CR user has a reputation degree which is initialized and adjusted by the FC and used to weight the sensing result from the corresponding user in the fusion process at the FC. And then, two reputation degree adjusting methods are presented to manage the reputation degree of each CR user. Simulation results show that the proposed scheme can not only weaken the harmful influence caused by malicious CR users, but also alleviate the corrupted detection problem resulting from destructive channel condition between the primary transmitter and the CR user. Moreover, the detection performance of the fault-tolerant cooperative scheme, which has a feasible computational complexity and needs no instantaneous SNRs, is close to that of the optimal scheme.     

遥控监测系统

本文通过对Ｒａｄｐｈｏｎｅ ２０００ＤＸ型遥控监测设备的介绍,阐述利用遥控监咱的方法监测广播效果是一种十分经济、方便快捷的手段,正在被世界各国普遍接受和使用。     

地市级电视台总控系统设计与分析

本文分析了地市级电视台总控系统的作用 ,指出总控系统的设计原则和设计考虑要点以及设备选购策略 ,详细介绍了扬州电视台总控系统的构建方案和总控系统的安全可靠性措施。     

红外无线数字通信

本文介绍了计算机领域正在兴起的一种通信技术－－红外无线数字通信，介绍了其工作原理及组成结构，目前已有的两个标准：ＩｒＤＡ及ＩＥＥＥ８０２．１１。对国外已有的产品及专用ＩＣ进行了总结，并就国外的一些研究成果作了简要综述。     

一种测量EDFA增益谱的新方法

本文提出一种利用光环形腔测量ＥＤＦＡ增益谱的新方法，简介了该方法的原理，用该方法对一ＥＤＦＡ的增益谱进行了测量，并与传统测量方法进行了比较     

Electroluminescence and Laser Emission of Soluble Pure Red Fluorescent Molecular Glasses Based on Dithienylbenzothiadiazole

Soluble molecular red emitters 1a / 1b are synthesized by Stille coupling from 2‐(3,5‐di(1‐naphthyl)phenyl)thiophene precursors. The compounds show emission maxima at ca. 610 nm in CH₂Cl₂ solution and 620 nm in solid films. Replacing the n‐hexyl substituent by 4‐sec‐butoxyphenyl produces a marked increase of glass transition temperature (T_g) from 82 °C to 137 °C and increases the solubility in toluene and p‐xylene, thus improving the film‐forming properties. Cyclic voltammetry shows that the compounds can be reversibly oxidized and reduced around +1.10 and ?1.20 V, respectively. A two‐layered electroluminescent device based on 1b produces a pure red light emission with CIE coordinates (0.646, 0.350) and a maximal luminous efficiency of 2.1 cd A^?1. Furthermore, when used as a solution‐processed red emitter in optically pumped laser devices, compound 1b successfully produces a lasing emission at ca. 650 nm.     

SPIHT静止图像压缩技术研究

JPEG2000的静止图像压缩算法具有很多优良特性,其核心算法是EBCOT,构造复杂、硬件实现难度大。而基于SPIHT算法的图像压缩效率接近EBCOT,但结构简单、易于硬件实现。通过对SPIHT和JPEG2000算法进行融合,提出了一套压缩比高、可实现由有损到无损、码流渐进传输的静止图像编码方案,并对SPIHT算法与(9,7)小波提升算法的融合方法进行分析研究,所构造系统性能与JPEG2000算法接近,具有较好的应用前景。     

Turbo乘积码在Rayleigh信道下的性能研究

Turbo乘积码（TPC）自从被提出以来表现出了优异的性能。研究了利用扩展汉明码作为其子码的TPC在Rayleigh信道下的性能．给出了不同的子码以及不同的迭代次数下的性能曲线,仿真结果表明了TPC在Rayleigh信道中同样有较强的纠错能力。     

IPTV计费系统与SP系统间接口的实现方案

IP电视(IPTV)业务正逐渐走向实际运营阶段,成为电信运营商的主流宽带业务.为了IPTV业务的长期有序发展,迫切需要建立适合IPTV业务运营的计费系统.文章描述了基于IPTV增值业务平台的计费系统的总体构成,说明了该系统中IPTV业务运营平台与服务提供商(SP)系统之间接口的定义,在此基础上详细分析了该接口与计费相关的功能需求,最后,给出了该接口的实现方案.