How to Create and Demodulate Custom OFDM Signals
애플리케이션 노트
A custom OFDM signal is comprised of a single repeating frame, where three different resource blockscould be included as shown in Figure 1:
- Preambles, which are used to acquire symbol timing and carrier frequency synchronization, as well as automatic gain control adaptation, channel estimation, and initial phase reference estimation
- Data, which are the actual symbols transmitting the information
- Pilots, which can be used for phase tracking, channel estimation, coarse and fine frequency synchronization, and timing synchronization
Each of these components takes up a certain section of time (symbols) or frequency (sub-carriers) depending on the wireless communication standard being used. This standard also determines the number of symbols and the number of sub-carriers in a single frame.
Preamble and data blocks are distributed in time across different symbols, usually starting with preamble and followed by data blocks, while pilots are distributed in frequency across different subcarriers either in dedicated symbols or in the same symbols as the data.