说明：  OFDM即正交频分复用技术，多载波调制的一种。其主要思想是：将信道分成若干正交子信道，将高速数据信号转换成并行的低速子数据流，调制到在每个子信道上进行传输。。每个子信道上的信号带宽小于信道的相关带宽，因此每个子信道上的可以看成平坦性衰落，从而可以消除符号间干扰。而且由于每个子信道的带宽仅仅是原信道带宽的一小部分，信道均衡变得相对容易。
(Orthogonal Frequency Division Multiplexing (OFDM) is a kind of multi-carrier modulation. The main idea is to divide the channel into several orthogonal sub-channels, convert high-speed data signals into parallel low-speed sub-data streams, and modulate them to transmit on each sub-channel. The signal bandwidth on each sub-channel is less than the correlation bandwidth of the channel, so it can be seen as flat fading on each sub-channel, which can eliminate inter-symbol interference. Moreover, since the bandwidth of each subchannel is only a small part of the original channel bandwidth, channel equalization becomes relatively easy.)