Understanding modulation in transmiting of wireless communication
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Hi everyone ^^
I have a question about modulation in transmition of singular antenna device as follow.
As I understand, for example, we are working with an OFDM system with 64 subcarriers.
We need to break our sequence of bits into blocks of 64 symbols to transmit at a time. So we need to transmit 64 symbols (=8*64 bits in 64-QAM, or 4*64 bits in 16-QAM) at a time.
We feed these 64 modulated values into 64 frequencies according to 64 subcarriers and then transmit them.
To work with the convolution
, we need to represent our signal (from frequency domain) into time domain using IDFT.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1466956/image.png)
The above is what I understand after reading the example Equalization, Convolution, and Cyclic Prefix AdditionOpen in MATLAB OnlineCopy Code Copy Command.
But I have questions like:
- How can we transmit those 64 symbols in 64 subcarriers at one time with a single antenna device? does the device have to transmit those symbol in 64 time slots, as it just can transmit 1 symbol at a time?
- How should I understand the signal after IDFT? as I understand, the chain of signals in 64 frequencies became a chain of signals in 64 time slots. But I think it is not really correct. Or they are just "imaginary" time slots?
(Now I do not see that the example mention the assumtion of 1 single antenna). I am very confused about these questions as I am new to this signal processing.
Thank you in advance ^^
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