Within a wireless opportunistic network,one of the lucky users gets an opportunity to utilize thewhole radio resource.However some of the unlucky users keep silent during an unexpected period result-ing from severe wi...Within a wireless opportunistic network,one of the lucky users gets an opportunity to utilize thewhole radio resource.However some of the unlucky users keep silent during an unexpected period result-ing from severe wireless environment and imperfect scheduling algorithms .An opportunistic cooperationprotocol is proposed that can achieve equivalent performance measured in terms of outage probability,inwhich scheme the opportunistic user helps to relay what need retransmitting indicated by the destinationand selects the appropriate power allocation to pursue fairness.The proposed scheme deploys superposi-tion coding and successive interference cancellation at relay and destination,respectively .To improve thespectral efficiency,the modified cooperation architecture involves two opportunistic users which work inturn.The simulation results demonstrate that the protocol obtains better performance compared with theconventional methods.展开更多
基金supported by the National Nature Science Foundation of China(No.60674009)the High Technology Research and Development Programme of China(No.2006AA01Z270)
文摘Within a wireless opportunistic network,one of the lucky users gets an opportunity to utilize thewhole radio resource.However some of the unlucky users keep silent during an unexpected period result-ing from severe wireless environment and imperfect scheduling algorithms .An opportunistic cooperationprotocol is proposed that can achieve equivalent performance measured in terms of outage probability,inwhich scheme the opportunistic user helps to relay what need retransmitting indicated by the destinationand selects the appropriate power allocation to pursue fairness.The proposed scheme deploys superposi-tion coding and successive interference cancellation at relay and destination,respectively .To improve thespectral efficiency,the modified cooperation architecture involves two opportunistic users which work inturn.The simulation results demonstrate that the protocol obtains better performance compared with theconventional methods.
文摘西方的符号学与《周易》从出发点到落脚点都是不同的。尽管有这种胎生的异质性,但两者之间还是存在所谓符号这样的重要交点。本文将对形成西方符号学分支之一的人物查尔斯·桑德斯·皮尔斯(Charles Sanders Peirce)的符号学思想与《周易》进行比较哲学的考察。皮尔斯符号学的特征在于泛符号主义(pansemiotism)和连续主义(synechism),即把存在于宇宙中的所有一切都作为其对象领域,把所有事物都当作连续体来把握。与弗迪南·德·索绪尔(Ferdinand de Saussure)以语言为中心来分析符号相比,皮尔斯更倾向于根据思维来分析符号,即通过表象体、对象体和解释体三者关系来分析符号。为了再现本质对象,皮尔斯提出了符号三分法,即指示符、像似符和规约符。他还提出了不同于传统方法论的假设推理法,即对现有事实推论出最好或最近似的说明的方法。把皮尔斯符号学观点运用于《周易》,则卦象、卦辞和卦意是实现《周易》符号过程的三要素,《周易》符号具有类像的规约符号性质。占术范式是根据其定性的本性而被规定特征的特殊知识模型,假设推理法是占术范式中特征性的思维方式,对于科学发现具有重要意义。
