About the modulation for the DVB-H ?

[mckinson]

Hello guys :


These days ,we found the DVB-H has the modulatio scheme : QPSK ,16QAM ,OFDM . Why need these 3 modulation ? what is the relationship between the 16QAM and OFDM ? I am confusion .Best regards.

 

[samuraign]

for acheiving data rates
we can use 16QAM when compared to QPSK.

Check once the ETSI EN 300 744 DVB standard.

 

[mckinson]

Great ,but what is the OFDM function ?

Added after 2 seconds:

Great ,but what is the OFDM function ?

 

[shameemkabir]

there is no relation between 16 QAM and OFDM.

OFDM is a technology where you subdivide the available frequency bandwidth like FDM (here it is called subcarrier) with overlapping frequency and transmit the data (16 QAM data in your case) in individual subcarrier. Since the subcarriers are orthogonal, data can be received although the frequency are overlapping. So, data can be transmitted/received in parallel in different subcarriers which increase the data rate.

To know a bit more, google OFDM.