基于容量最大化的多用户MIMO-OFDM子载波分配算法

针对多用户MIMO-OFDM通信网络,提出了一种基于系统和容量最大化的子载波分配算法。 通过对MIMO-OFDM系统和容量公式进行分析,提取出子载波分配的判决参数,再利用匈牙利 算法对子载波进行分配,同时分析了分配后系统平均容量的统计特性。为了兼顾公平,又提 出了传输速率最小的用户传输速率最大化的子载波分配算法。仿真结果表明,所提容量最大 化算法能使系统和容量达到全局最大值,且具有较低的复杂度。     

多用户MIMO-OFDM系统中一种子载波分配算法

介绍了多用户MIMO-OFDM系统中的Hungarian子载波分配算法，然后针对其计算复杂度过高的缺陷，提出一种局部最优的子载波分配算法，并与Hungarian子载波分配算法进行仿真比较。结果表明，该算法使系统总数据速率仅下降1．7％，而其计算复杂度却大幅减小，提高了资源分配的效率，符合高速无线系统资源实时分配的要求。     

速率比例公平下多用户OFDM系统的自适应资源分配

在多用户正交频分复用（MU-OFDM）系统中,考虑各个用户之间具有比例数据传输速率限制 条件下的一种公平的自适应资源分配方案的最优算法计算量巨大,为此,提出了一种将子信 道分配和功率分配相分离的次优算法。首先,在假设相同功率分配的情况下进行子信道的分 配,然后在保持一定比例公平条件下使总容量最大时进行最优功率分配。对该算法的仿真表 明,在用户数为2、子信道数为10的系统中,所提算法的容量性能接近最优算法,而计算量 由指数增长变为线性增长。所提资源分配算法的总容量比以前的算法在用户间的分配更公平 也更灵活 。     

基于比例速率保证的信道误差OFDMA中继系统资源分配

针对存在有信道估计误差的正交频分多址（OFDMA)中继系统,在考虑用户传输中断概率的同时,提出了满足不同用户最小服务质量（QoS）需求和比例公平性约束条件下的中继选择、子载波分配和功率分配的联合优化问题,建立了以最大化系统总容量为目标的优化模型。在此基础上以速率最大化为目标进行最佳中继选择,并通过动态子载波分配来满足用户的最小QoS需求和比例公平性,最后采用拉格朗日乘子法来得到最优功率分配方案。仿真结果表明,此算法在降低用户中断概率的同时,提高了系统吞吐量并保证了用户速率的比例公平性。     

一种基于用户需求的OFDM系统资源分配算法

提出了一种新的基于OFDM多用户通信系统的资源分配算法。该算法在总功率限制和用户数据率要求下，通过以下两步实现子载波、比特和功率的动态分配：第一步，基于用户的平均信道增益和数据率要求进行资源初分配（每个用户分配多少个子载波、功率）；第二步，对步骤1中的结果进行调整，最终决定每个用户分配到的子载波、功率以及比特载入方式。相比于Hujun Yjn等人提出的另一种基于用户需求的算法，新算法的基站发射功率略有增加，但复杂度大为降低，在实际运用中更有利用价值。     

多用户OFDM系统的次最优分配算法

本文提出了一种多用户OFDM系统中次最优的自适应载波、比特和能量分配算法。此算法利用各子载波的瞬时特性,在保证各个用户服务质量(QoS)的前提下,通过合理地分配子载波并调整各个子载波调制等级,达到降低总发射功率的目的。该算法相对于最优算法具有简单、公平、高效的特点。仿真实验表明,该算法的性能接近最优算法。     

基于改进智能水滴算法的多用户OFDMA系统资源分配

在正交频分多址（OFDMA）系统中，合理的资源分配对于提升系统的性能具有重要的意义。针对多用户OFDMA系统，对最大化系统容量为目标的资源分配算法进行研究，提出了一种基于智能水滴算法的无向全连通图资源分配模型，以无向全连通图的顶点集和边集来描述用户与子载波之间的匹配关系。在此基础上，进一步对智能水滴算法进行改进。仿真结果表明，在满足用户比例公平性的条件下，与蚁群算法相比，基于改进智能水滴算法的全连通图分配方案能够提高2.17%~4.91%的系统速率，同时具有更快的收敛速度，提高了系统性能。     

异构网中载波聚合系统的成员载波选择和干扰协同

为了解决下一代演进移动通信系统在异构网场景由于低功率基站在高功率基站覆盖区 域的随意分布而导致的小区间干扰问题及容量速率限制,提出了一种载波聚合系统的成员载 波选择和干扰协同方法。该方法基于修正的载波公平比例准则,动态地在小区间协同选择成 员载波。为了进一步提高低功率节点的系统容量,设计了新的基于调和平均数的用户小区选择 准则及算法。仿真结果表明,与频率复用因子为1的系统相比,设计的方法由于静默了部分 高功率节点用户成员载波,从而使低功率节点用户获得更多的选择机会,可提高低功率节点 小区的容量。     

UFMC系统在多径衰落信道中的干扰消除

通用滤波多载波(UFMC)是5G通信系统中的关键技术，能够降低带外泄露。但是在多径衰落信道下UFMC系统会受到符号间干扰（ISI）和多普勒效应产生的载波频率偏差的影响，从而使系统的性能下降。为了消除系统中的干扰，提出了一种迭代最大似然算法。该方法主要通过迭代最大似然算法（ML）计算出载波频率偏差，把估计出的结果作为初始值并运用迭代的方法得到最终的载波频率偏差，当达到收敛区间时，迭代结束；最后利用相位旋转的概念补偿载波频率偏差并运用最小二乘算法更新信道响应信息，减少该系统干扰。仿真结果表明，在信噪比大于10 dB时，随着信噪比的增大，算法能够有效地抑制系统中的干扰，提高UFMC系统的性能。     

多用户MIMO系统广播信道的连续块对角化预编码算法

针对块对角化（BD）算法无法满足各个用户的需要、串行优化（ SO）算法排序复杂、容量较低的问题,提出了一种连续块对角化（SBD）算法。该算法按照 各用户的信道条件、服务质量（QoS）需求给用户定义不同的优先级,并按优先级次序进行 块对角化,后续用户在对高优先级用户及同优先级用户不干扰的条件下采用块对角化法抵消 共信道干扰（CCI）,功率分配方式采用等功率分配。数值仿真表明,该算法在不增加计算 复杂度的前提下 ,基本满足各个用户的需求。     

Universal Coverage, Pinpoint Illustration and Profound Impact HTC 2008 Intermedia Recommendation and Introduction Meeting

Holding 88 percent of train media resources across China, based on "Time Cube", on the 2008 Intermedia Recommendation and Introduction Meeting on December 19, 2007, HTC announced its high-profile strategy of tour marketing and tapping the immeasurable potentials on the train. Meanwhile, HTC officially launched its brand new product Olympic Train on the meeting, providing a fabulous platform for all the brands that are prepared to do a smart marketing on the occasion of 2008 Olympic Games.     

Market presence in China strengthened Network growth and Dual-Chinese-Hub Strategy More frequet Flyer Benefit——Air China and shanhai Airlines Join Star Alliance

In the end of 2007, Air China Limited (hereinafter "Air China") and Shanghai Airlines, formally joined Star Alliance at a ceremony held in the new Terminal Three at Beijing Capital International Airport. With the addition of the two Chinese airlines, Star Alliance now has 19 member carriers operating 17,000 daily flights to 897 destinations in 160 countries.     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

A World of Love 2008 Music Grand Ceremony

Under the guidance of the theme slogan of the 29th Olympic Games - One World One Dream, with dream, love and dedication as its theme, the 2008 Music Grand Ceremony ＆ 1000 People Charity Concert on 100 days cotmtdown to Paralympic Gamesis officiaily launched on December 22, 2007. The 2008 Music Grand Ceremony is sponsored by China Disabled Persons＇ Federation, and co-hosted by National Paralympic Committee of China,     

China''''s National Oil Reserve Center was Born

Aseries of events that occurred in October 2007, are rewriting the history of China's energy industry: November 3 an Energy Law Committee asked the public for suggestions on improvements; forty top experts came together to form the National Energy Expert Advisory Committee on November 6; and the National Oil Reserve Center (NORC)became the nerve centre of oil reserves on November 18. Yet, behind the progress of these recent activities remains the fact that international oil prices still hover around a very high price of US$ 90/barrel, and China's oil imports are close to accounting for half of its total oil reserves.     

MUYANG GROUP

With its headquarters in the historic city of Yangzhou,Jiangsu Muyang Group Co.,Ltd has since its founding in 1967 grown into a well-known group corporation whose activities cover research ＆ development,project design,manufacturing,installation and services in a multitude of industries including feed machinery and engineering,storage engineering,grain machinery and engineering,environmental protection,conveying equipment and automatic control systems.     

2007 China Harbor Ten People

2007 China Harbor Ten People elected the entrepreneurs who contributed a lot to port economy and enterprises this year trough their talent management.These ten people embody their social responsibility,professional skills,creative ability,and charming personality.Bearing full confidence in China＇s port economy,the port entrepreneurs are brave enough to explore a brand new area,so as to promote harbor economic development. At the very beginning of 2008,China Shipping Website,Dalian Maritime University,and China Port and Shipping In- stitute jointly select the 2007 China Harbor Ten People,demonstrate port entrepreneurs＇ stunning minds,disclose their secrets to success,and providing abundant experiences to others in harbor development.The top ten people are various excellence during the ups and downs harbor development.