LTE学习笔记第3篇OFDM

FDM：单载波系统

GSM单个载波占用频谱宽度为200千赫兹，在实际应用中用户仅能有效利用其中约1/2（即约1万千赫兹）的有效频率范围。这些剩余的频率则被用来作为保护频段以防止信号间的干扰

多载波：仍然需要中间设置隔离间隔，并且带宽利用率较低。相邻载波之间存在一定的干扰。

Orthogonal Frequency Division Multiplexing (OFDM) is known for its ability to enhance spectral efficiency. Its constituent subcarriers are inherently orthogonal in nature, thereby eliminating the need for guard intervals or spacing tones. Moreover, the frequency bands allocated to these subcarriers can overlap without causing interference. Consequently, compared to conventional multi-carrier techniques, OFDM achieves significantly higher frequency utilization.