I have made some searches and have below questions on this.
So far I understand that there two methods for time synchronization which
are data-aided and non-data aided methods, and in the data-aided methods
the training subcarriers are included in OFDM symbol and they are
correlated with the known training subcarriers at the receiver and the
time of the peak of the auto-correlation is the time delay (tao)of the
channel and this means the OFDM symbol reaches the receiver after this tao
delay.
My questions here are;
1-For time synchronization, if the data-aided method is used, should the
one complete OFDM symbol contain all training subcarriers and then all are
correlated with the known trainings one by one at the receiver?
2-Or the OFDM symbol contains a few training subcarriers and when they are
received by the receiver each of the trainings is correlated by the known
pilots?
Thanks!