I am simulating a SFBC OFDM system in MATLAB for 4 transmit antennas and one receive antenna system (G4 code with rate 1/2) using 16 QAM as baseband modulation technique.
The code works well for equal energy modulation schemes like MPSK but is not able to calculate accurate bit error rate performance for unequal energy modulation like MQAM.
please suggest what changes I have to do in the program to run it for 16 QAM modulation too.
While it is generally assumed that SFBC-OFDM
using orthogonal designs is a technique limited to
channels where the delay spread is small compared
to the symbol duration, some authors have shown that using
a ZF receiver, it is possible to extend the range
of application of SFBC-OFDM.
See following link (Paper) for understanding.
http://easytp.cnam.fr/leruyet/Publications/ofdm04_2.pdf
Thank you for the reply sir. I read the paper you attached here. But the problem I am facing is that the MATLAB code is working well for PSK like QPSK and 16 PSK but fails to give satisfactory results for 16 QAM .
Dear Daljeet,
The system works also for QAM modulated symbols. The receiver must be built to perform exactly the inverse operations of transmitter that is the inverse sfbc and demapping of the qam symbols. It is so that if you loop back your signal from the your transmitter to your receiver you must obtain the same input signal at the output of the transmitter. Then after that you add the channel and study the error performance.
You can not study the error performance without correctly building your system.
So, the paper in the given website will be helpful to you:
www.ncc.org.in/download.php?f=NCC2007/7.1.3.pdf
wish you success
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