融合通用滤波多载波的非正交多址接入技术

典型的非正交多址接入技术（Non-orthogonal Multiple Access,NOMA）有稀疏码分（Sparse Code Multiple Access，SCMA）、多用户共享（Multi-user Shared Access，MUSA）、图样分割（Pattern Division Multiple Access，PDMA）等。为了研究这三种典型的NOMA技术与通用滤波多载波复用技术（Universal Filtered Multi-carrier,UFMC）技术结合后的性能，将三种典型的NOMA与UFMC结合，然后分析比较了它们的误码率性能，通过仿真对比得出UFMC-SCMA系统相比其他两种结合系统具有更好的系统性能。为了更进一步验证UFMC-SCMA系统的优点，还将其与热门的OFDM-SCMA系统进行对比。研究结果表明，由于UFMC-SCMA系统具有码本的稀疏性以及近似最优的信息传递算法（Message Passing Algorithm，MPA）检测方案，并采用子频带滤波，有效降低了误码率并提高了频谱效率，因而其具有较好的系统性能。     

SIMO-NOMA系统分步多用户检测策略

上行免调度非正交多址接入（NOMA）系统中,针对低信噪比情况下通过压缩感知技术联合检测活跃用户和数据的误码率性能比较差的问题,提出了分步多用户检测策略。该策略考虑信号的稀疏度对系统检测性能的影响,理论分析得出了检测成功概率的下界,以降低稀疏度来提高重构概率;结合压缩感知硬融合算法（CS-HFA）,对稀疏信号进行二次筛选,最终实现信号的精确检测。仿真结果表明,随着信噪比、活跃用户数或者过载率的改变,改进方案表现出较好的系统检测性能。     

基于OQAM-OFDM的NOMA通信系统设计

针对传统基于正交频分复用（OFDM）调制波形的非正交多址接入（NOMA）通信系统存在的旁瓣衰减较慢问题,提出了一种基于交错正交幅度调制的正交频分复用（OQAM-OFDM）波形的NOMA系统设计方案。所提设计方法通过在典型NOMA系统设计中加入OQAM预调制和滤波器组滤波等处理,有效加快旁瓣衰减,实现了较好的频域聚焦性能。仿真结果表明,提出的设计方法不仅有效提高了系统的频谱利用率,而且在抵抗多径干扰时误码率有所降低。虽然重点研究了通信下行链路,但是所得结论同样适用于上行链路。     

上行SCMA系统的动态子图检测算法

面对未来网络需求量的爆炸性增长，稀疏码多址接入（Sparse Code Multiple Access，SCMA）作为一种基于码本的非正交多址技术，在用户连接数、频谱效率和低时延都有很大的提升。由于码字的稀疏性，SCMA采用消息传递算法（Message Passing Algorithm，MPA）实现多用户检测，但是复杂度还是相对较高，以至于很难应用于实际系统。为了解决上述问题，提出了一种动态子图消息传递算法（Dynamic Sub-graph Message Passing Algorithm，DS-MPA）进行信号检测。DS-MPA利用剩余值来确定下一次迭代的子图，减少了资源节点的更新用户数量，达到了降低复杂度的目的。仿真结果显示算法性能几乎无损并且降低了1/3左右的复杂度。     

一种用于SCMA系统的混合期望传播检测方法

作为一种新的非正交多址接入技术,稀疏码多址接入（Sparse Code Multiple Access,SCMA）被提出以支持大规模连接。基于稀疏因子图,SCMA利用低复杂度的消息传递算法（Message Passing Algorithm,MPA）来实现接近最优的多用户检测。但是,传统MPA的复杂度仍然很高。为了灵活地控制算法的复杂性,提出了一种混合期望传播检测算法用于SCMA检测,建立算法复杂度与信道阈值之间的关系,利用信道阈值控制算法复杂度。此外,将混合期望传播检测算法与消息回退机制相结合以提高性能。仿真结果表明,与其他检测方案相比,所提算法可以灵活地在算法性能和计算复杂度之间进行折衷。     

外部信息自适应更新的SCMA系统译码方案

现有上行稀疏码多址接入（Sparse Code Multiple Access，SCMA）通信系统采用的译码算法中，基于串行策略的消息传递算法（Message Passing Algorithm，MPA）因其在每次迭代过程只选择单个消息进行更新，存在着收敛速度较慢等问题。针对以上问题，提出外部信息自适应更新的MPA算法，每次迭代过程中自适应选取多个残差值较大、相互独立的节点，更新其外部信息以达到提高计算效率的目的。仿真结果表明，该算法可有效提升译码性能，在计算复杂度与译码性能之间取得了较好的平衡。     

一种中继卫星系统多址应用设想

通过中继卫星系统中码分多址（Code Division Multiple Access,CDMA）/ 时分多址（Time Division Multiple Access,TDMA）能力、实现复杂度、容量等方面的分析,结合中继卫星系统传输数据在固定站点接入的特点,设想了一种前向采用同步CDMA、返向采用TDMA的混合多址应用方式。该方式充分利用了CDMA和TDMA方式的优点,巧妙地利用前向通道实现了TDMA的时隙同步,解决了CDMA方式下存在的多址干扰、远近效应、用户数扩展受限以及TDMA方式下的复杂时隙同步等问题,且应用灵活,实现简单,多用户数扩展性好,在工程应用上具有一定的参考意义。     

一种适用于D2D通信的启发式接入算法

直通通信（Device-to-Device,D2D）技术是5G移动通信的关键技术之一,蜂窝网络中的D2D通信用户接入技术及其性能研究等已成为热点问题。基于一种新型随机几何网络模型,通过研究D2D用户对蜂窝用户的上行链路频谱资源的复用,提出了一种D2D通信启发式接入算法,并同随机接入算法进行了比较分析。仿真结果表明,随机几何模型易于分析链路的信干噪比,更符合未来移动通信密集组网和用户分布特点;该模型下的启发式算法比随机算法的性能更优,算法具有收敛快、接入性能好和接入简单的特点,具有更好的实用价值。     

一种基于CoMP的随机接入方案

提出了一种新的基于协作多点传输和接收（CoMP）技术的多发随机接入流程,并根据 随机接入的目的和业务类型设计了接入优先级,在此基础上设计了一种新的随机接入方案, 对 不同类型的随机接入请求提供不同的接入机制,以保证边缘用户的接入性能和满足不同业务 的QoS需求。仿真结果表明,与LTE标准随机接入方案相比,该方案对系统整体接入性能略有 提高,且大大提高了边缘高优先级用户的接入性能。     

LDPC编码MC-LDS系统联合因子图的改进PEG设计

作为非正交多址（Non-orthogonal Multiple Access,NOMA）技术之一,基于稀疏因子图的多载波低密度序列（Multi-carrier Low-density Signature,MC-LDS）技术由于其译码复杂度较低,可以与同样基于稀疏因子图的低密度奇偶校验码（Low Density Parity Check Code,LDPC）同时使用。MC-LDS技术的检测算法和LDPC 的译码算法都是基于稀疏因子图上的消息传递算法（Message Passing Algorithm,MPA）,但现有研究中,对于MC-LDS和LDPC稀疏因子图的设计一般独立进行,得到的结果往往不是最优的。为此,提出一种将LDPC与MC-LDS稀疏因子图进行联合分析设计的方法,采用改进的渐进边增长(Progressive Edge Growth,PEG)方法,消除了MC-LDS与LDPC联合因子图中各自的因子图之间互相耦合导致的短环,构建了性能良好的联合稀疏因子图。仿真结果表明,对于不同的LDPC码长,所提方案获得了0.5~0.6 dB的性能增益。     

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.     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.     

Trade Promotion from Neighborhood

If you are considering to trade with companies in Japan or expanding your .business to Japan, we are ready to help from the very beginning.＂ You will find this greeting at the first sight on the Chinese website of Japan External Trade Organization （JETRO）. JETRO has committed itself in delivering highly efficient and quality services to meet the demand of internal and external customs including Japanese companies, hence winning a good reputation in the international trade arena. In recent years, with its priority in advancing business cooperation in South and East Asia, JETRO has made great achievement in promoting trade between China and Japan. Therefore, China＇s Foreign Trade interviewed Mr. Yoichi Maine, Deputy Director General of JETRO BEIJING.     

Auto Parts Market Potential Coming into Surface

Looking at the increasingly fierce competition in the world auto market. global automobile manufacturing industry, taking Europe, the U.S. and Japan as representatives, is gradually forming a new type of relationship, mutual cooperation between whole vehicle and parts manufacturers. We can clearly see that auto parts manufacturers have become independent from the whole vehicle manufacturing companies, which means that the former structure of auto industry has greatly changed, and a new relationship,     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."