今天在读5G通信技术里面最基础的技术OFDM。
OFDM：OFDM stands for Orthogonal Frequency Divisition Multiplexing.
中文解释：正交频分复用
顾名思义三个特征：
- Orthogonal ---正交，好理解，相位差90°
- Frequency Division---频分，好理解，把宽的频带细分成子载波
- Multiplexing----复用，一直未能理解这个“复用”，什么鬼？不知道谁翻译的这个鸟东西。
直到今天读http://www.sharetechnote.com/html/Communication_OFDM.html
==> OFDM is a technology that we split a wide frequency band into many small frequencies (we call this split frequencies as subcarriers) and carry data onto each of these sub carriers as illustrated below. In other words, we 'devide a wide frequency band' into multiple small/narrow frequencies. This is the meaning of 'Frequency Division'. Since all the data on each of these subcarriers are transmitted simultaneously, we can say this is a kind of 'Multiplexing'.
才明白，原来是多路子载波同时传输数据，妈蛋，误人子弟啊！以后还是读英文原始文档吧，虽然困难，不至于困惑这么多年！