what is actually a OFDM symbol?

Question

What actually a OFDM symbol?How do you actually map it to the actual user data, lets say the user sends a bit 0 or 1?

Comments

Can you put more info, as it is not clear what you want to ask?

Answer 1

In LTE, Symbol depicts the amount of data you will throw in between particular time frame.

The que is how much data we can send in one Symbol that depends upon the modulation which modulation technique we are using:

QPSK (= 4QAM)   2 bits per symbol
16QAM   4 bits per symbol
64QAM   6 bits per symbol

What is OFDM Symbol
This particular means the symbol will be send in orthogonality form. In LTE the symbol length is 66.7 micro seconds.

Now coming to your second query how it is mapped.
Actually it is simply a Digital to Analog conversion. We simply does the conversion and maintain the same identifiers which identifies whose data it belongs. So it usually works with Physical Layer which present in e-NodeB if it is Network Side or by UE physical Layer.