基于OFDM的数字广播系统模型研究及子载波数目确定

作为时变的多径信道,中短波信道的时变性导致基于OFDM数字调幅广播系统各个子信道间产生干扰,简称ICI。该文首先分析OFDM系统在一般时变多径信道的模型,在此基础上推导了中短波信道时变特性在OFDM系统中所产生的ICI公式,最后利用该公式通过计算机数值计算确定在ICI可忽略不计的情况下,OFDM系统的总的子载波数目N的最大值,而该值的确定对于基于OFDM的数字调幅广播系统是非常重要的。

Research about the ofdm-based digital broadcasting system model and decision about the number of the total subcarriers

As time-variant multipath channels, the time-variant property of MW and SW channels causes the interchannel interfere (ICI) between different subchannels of OFDM-based digital amplitude modulation broadcasting (DAMB) system. In this paper, the OFDM system model is analyzed in MW and SW channels, and ICI due to time-variant channel is formulated. Finally, by computer simulation, the maximum number of the total subcarrier in OFDM system is estimated under the condition that ICI is much smaller compared to signal. This value is very important for the DAMB system.