OFDM —— OFDM(Orthogonal Frequency Division Multiplexing)即正交频分复用技术,实际上OFDM是MCM Multi-CarrierModulation,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。正交信号可以通过在接收端采用相关技术来分开,这样可以减少子信...
首先观察openair1/README.TXT 可以发现每个目录下至少都有一个def.h文件来声明结构体和函数,extern.h来声明外部变量以及vars.h文件来声明变量,知道MODULATION是存放调制解调操作的 进入openair1\PHY\MODULATION\ofdm_mod.c,找到OFDM调制代码,OFDM输入信号在经过信道编码,交织,调制后成为比特流,通过IFFT及那个频域输入映...
Y= ofdmmod(X,nfft,cplen,nullidx)inserts null subcarriers into the frequency domain input data signal prior to performing OFDM modulation. The null subcarriers are inserted at index locations from 1 tonfft, as specified bynullidx. For this syntax, the number of rows in the inputXmust benff...
Orthogonal Frequency Division Multiplexing (OFDM) is the multicarrier digital modulation technique used by modern wireless communications systems such as 5G and LTE cellular, and WiFi. The advantages of OFDM over other techniques, such as single carrier QAM, include support of higher data rates with...
Therefore, in every control module of OFDM modulation and demodulation, some logic is dedicated to signal alignment.因此,在OFDM调制解调中的每个控制模块中都有一些逻辑信号专用于信号对齐。 该实例中也通过Avalon Stream信号sink_ready(输入准备好信号)和source_ready(输出准备好信号)来支持背压。循环前缀插入...
Refer to thecomm.OFDMModulatorSystem object™ which can also be used to implement the CP-OFDM modulation. F-OFDM Receiver with No Channel The example next highlights the basic receive processing for F-OFDM for a single OFDM symbol. The received signal is passed through a matched filter, foll...
地利用频带资源,实现高码速率传输;对于衰落或窄带干扰,可能会导致单载波通信系统瘫痪,而OFDM 系统只影响几个子信道,可采用针对受干扰的子信道降低数据传输速率等方法来保证星间通信系统的通信质量;OFDM 技术起源于模拟调制的频分复用( frequency division multiplexing ,FDM)和多载波调制( multi-carrier modulation , ...
OFDM,OFDM(Orthogonal Frequency Division Multiplexing)即正交频分复用技术,实际上OFDM是MCM(Multi Carrier Modulation),多载波调制的一种。OFDM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。正交信号
数字基带调制(Digital Baseband Modulation)是将数字信号转换为适合传输的信号形式的过程,主要通过改变载波信号的某些特性(如幅度、相位或频率)来表示数字数据。解调(Demodulation)是调制的逆过程,即从接收到的调制信号中恢复原始数字数据。这些过程在通信系统中至关重要,确保数据能够在噪声和干扰的环境中可靠地传输和接收。