A group of orthogonal frequency carriers are used in ofdm system to improve the using rate of spectrum . if the orthogonal character can be held and ignore the inter - channel interference ( ici ) , the symbol error character of ofdm depend on the modulate of source codes . this dissertation propose the theoretic formula of ofdm - qam and ofdm - psk in this precondition 为了提高频谱利用率, ofdm系统使用了一组正交的子载波来传输信号,若能保证各子载波间的正交性不被破坏、不考虑信道间干扰( ici ) ,则ofdm系统的误码性能由信元调制方案的误码性能决定,文中推导了该情况下ofdm - qam和ofdm - psk的理论误码率公式。
At present , the fund industry steps into the prosperous stage , and ici said that in 2004 there is a net inflow of $ 49 . 78 billion into the mutual fund market , and capital funds amounted to $ 7 . 54 trillion . the amount of capital funds in the world is more than $ 10 trillion 目前全球证券市场基金业蓬勃发展,生机盎然,据美国投资公司协会( ici )表示, 2004年美国共同基金市场净流入497 . 8亿美元,使得基金整体资产增加至7 . 54万亿美元,目前全球基金规模超过10万亿美元。
In this chapter , cck codeword has been described . following this are the algorithm of cck receiver scheme , includeing maximum likelihood receiver under awgn channel - rake and rake - isi receiver based on the channel matched filter and decision feedback equalizer . chapter 5 is a report about the receivers performance simulations 在这一章中对cck调制及码字的特点进行详细描述，随后详细阐述我们所采用的几种cck接收机方案中的算法，包括加性噪声信道下的最大似然接收机、基于信道匹配滤波器的rake接收机、带isi删除的rake接收机(即rake - isi ) 、带isi和ici删除的rake接收机(即rake - isi ici )以及判决反馈均衡器。
Ofdm system is a very promising technology since it has many advantages , such as its high - efficient spectrum and ici interference avoidance . it can also easily connect with mimo and access technologies like fdma , tdma , and cdma . because different subcarriers can adopt different coding and modulation methods , the capacity of the channel is able to reach the optimum value Ofdm多载波调制解调系统,具有抗多径干扰能力强,频谱利用率高,可以与mimo技术、不同的多址接入方式相结合,可使信道容量到达最优,所以基于ofdm的多载波调制解调系统越来越得到广泛的应用。
This thesis is based on the theory of the unexpected release of energy in safety system engineering and applies the relevant principle in risk assessment . three kinds of methods , such as dow fire & explosion index , ici / mond index , grey clustering procedure and three mathematical models , such as bleve accidental model , vce accidental model , the model of leakage & diffusion of posionous gases are applied to the risk asssessment of lpg terminal 本文以安全系统工程中的能量意外释放理论为理论基础，根据安全评价的相关原理，综合运用三种方法：道氏火灾爆炸指数法、 ici mond法、灰色聚类法以及三个模型： bleve事故伤害模型、 vce事故伤害模型、有毒气体泄漏扩散模型，对液化石油气码头的储运进行了风险综合评价。
