GSM移动通信手机射频收发系统的设计与实现

提出了一种按照GSMPhase2 技术规范实现的GSM移动通信手机射频收发子系统的硬件方法。该系统采用了当今较为流行的DCR方案,并且支持GPRS应用,可工作在EGSM900和DCS1800双频段上。文中介绍了射频收发子系统的构成和基本原理,描述了系统设计实现的具体过程,为系统设计提供了必要的分析和计算。     

基于空时分组编码的MC-CDMA下行链路合并方案

基于空时分组编码的发射分集技术利用空间和时间分集 ,能有效抗多径 ,增强信道可靠性。将空时分组编码应用到MC -CDMA下行链路中 ,构建了一种新的多载波CDMA系统 (ST -MC -CD MA) ,通过在每个子载波信道中获得空间分集增益来提高系统性能。具体实现时 ,依据传统MC -CDMA信号合并方案 ,提出了ST -MC -CDMA空时译码后相应的四种合并方案。仿真结果验证了这 4种合并方案的优、缺点 ;并进一步证明 :在频率选择性瑞利衰落信道中 ,该系统比采用相同合并方案的传统MC -CDMA有明显的性能改善。     

Hierarchical structures of communication in a network organization

We analyze the intranet communication behavior of members of a company that was deeply committed to the principles of non-hierarchical communication structures and of post-bureaucratic organization. We observe a split between the symbolic activities for creating a non-hierarchical network organization and the actual intranet communication behavior of the organization members. In their daily communication on the intranet, they persistently reproduced hierarchical structures and official channels—elements typically associated with bureaucratic organizations. Further, we find many signals in the content of the intranet messages, reflecting a social hierarchy that has evolved within the organization. Thus, despite rhetoric to the contrary, our findings regarding this communication behavior show that, to all intents and purposes, this particular organization displayed characteristics similar to those of a traditional bureaucratic organization.     

A detail-free mediator

We present a cheap talk extension to any two-player, finite, complete information game, and ask what correlations over actions are implementable in Nash equilibria of the extended game. In the extension, players communicate repeatedly through a detail-free mediator that has been studied in Lehrer (1991) and in Gossner and Vieille (2001). The extension captures situations in which people can observe the opponentʼs face during the conversation. While Gossner and Vieille (2001) prove that no correlation can be securely implemented by using only this mediator, we prove a result closer to Lehrer (1991), namely, that the Nash equilibrium payoffs of the extended game essentially coincide with the correlated equilibrium payoffs of the underlying game. The contrasting results can be explained with our additional assumptions that the players can also communicate directly and, more importantly, the private messages sent to the mediator can be recorded and revealed later in the conversation.     

A consumer segmentation of nutrition information use and its relation to food consumption behaviour

Consumers need information such as nutrition tables to assess the nutritional value of a food product. Although a broad range of studies has examined consumers’ attention, perception and use of nutrition tables, relatively little is known about what types of consumers use what kind of nutrition information. Therefore, using data from the Swiss Food Panel, we conducted a cluster analysis of nutrition information usage and health and nutrition interest to determine whether consumers could be segmented into specific groups. We identified four segments, which we labelled Official Information Users, Internet Users, Moderate Users and Uninterested. We then determined the segments’ demographics, food frequencies and perception of food. Based on our findings, we provide suggestions for targeted interventions that stimulate healthy food choices among these four segments. Our findings imply that nutrition education or the improvement of nutrition labels is unlikely tostimulate nutrition information usage among all consumer types; some consumers may rather benefit more from environmental cues that prime healthy food choices.     

海南旅游文化传播的困境与对策——大众传播视角的思考

近年来，海南旅游业快速发展，但是总体来看海南旅游文化传播不够，当前海南旅游业正处于转型升级时机，加强旅游文化的传播有很强的现实意义。对海南旅游文化传播不够的原因进行了深入地分析，并且提出了相应的建议。     

涉外导游跨文化交际能力的培养

随着中国旅游业的发展,社会对涉外导游的需求越来越大,对导游的要求越来越高,而与此同时,中国目前的导游队伍无论是数量还是质量都无法适应旅游业进一步发展的要求。培养导游跨文化交际能力应做好以下三点：教学中加大对跨文化知识的传授;以学生为中心,培养学生交际能力;加大对学生进行中国传统文化教育。     

一种利用压缩感知改进的PMF-FFT扩频捕获算法

为了实现直接序列扩频（DSSS）信号快速捕获的同时降低数据量和硬件资源消耗，引入了压缩感知理论改进部分匹配滤波-快速傅里叶变换（PMF-FFT）算法，提出了基于压缩感知改进的部分匹配滤波-快速傅里叶变换（CSPMF-FFT）算法。该算法将PMF-FFT算法与压缩感知理论相结合，先对信号进行稀疏性分析和压缩观测，然后从少量压缩观测值中重构信号，并利用输出的峰值信息估算信号的多普勒频移和码相位，从而实现捕获。理论分析和仿真实验表明，相较于PMF-FFT捕获算法，CSPMF-FFT算法能在成功完成捕获的同时有效地减少相关器的数目和FFT变换的运算量，从而降低系统数据量和硬件资源压力，为基于压缩感知的扩频信号处理技术研究奠定了基础。     

Mobile communications – On standards,classifications and generations

The research question addressed in this paper is concerned with the manners in which the general technological progress in mobile communications is characterized and the reasons for the differences in these modes of manifestation. The relevance of this research question is that the different manifestation modes create a degree of confusion in communications and discussions on mobile technologies. At the same time, it should be recognized that different manners of categorizing technologies illustrate the fact that categorizations are based on different purposes of the classification exercises. Also, the paper discusses the role of the International Telecommunication Union (ITU) in the processes of mobile standardization.In common parlance, progress in mobile technologies is mostly referred to as generations. In ITU, the classification terminology is that of International Mobile Telecommunication (IMT) standards. In the specialized standards body with a central position in the standardization of core mobile technologies, namely 3GPP (3rd Generation Partnership Project), the terminology of ‘releases’ is used. In order to address the research question, the paper uses an analytical framework based on the differences and relationships between the concepts of standards, classifications and generations.     

群时延失真对扩频通信性能影响的仿真与分析

首先简要介绍了卫星通信中扩频系统的基本模型和表达式，给出了系统在失真信道中进行计算机仿真的基本模型。然后，利用通信系统仿真软件包ACOLADE，建立了扩频系统在群时延失真信道中的仿真模型，建立了群时延失真信道模型，进行了QPSK、QPSK＋DS、QPSK＋FH等体制在群时延失真信道的特性仿_真分析，最后得出了一些有一定参考价值的分析结果。