Comments on: Understanding an OFDM transmission http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/ Signal Processing for Communication Fri, 30 Jul 2010 01:36:27 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Krishna Sankar http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-33893 Krishna Sankar Mon, 26 Jul 2010 01:48:08 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-33893 @Afm: Have not written about MC-CDMA, will write in future... @Afm: Have not written about MC-CDMA, will write in future…

]]> By: Afm http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-33872 Afm Sun, 25 Jul 2010 18:43:38 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-33872 hi krisna, Could you do an article about understanding the MC-CDMA too? I know it is a little bit similar to OFDM and I have also read some paper on MC-CDMA. I just dont really get how to implement the coding (which is in frequency domain) and the message bit in Matlab. Do I need to multiply them together in the frequency domain or ifft the coding first and then multiply with message bit? Thanks hi krisna,

Could you do an article about understanding the MC-CDMA too? I know it is a little bit similar to OFDM and I have also read some paper on MC-CDMA. I just dont really get how to implement the coding (which is in frequency domain) and the message bit in Matlab. Do I need to multiply them together in the frequency domain or ifft the coding first and then multiply with message bit?

Thanks

]]> By: thieutuoc http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-32142 thieutuoc Sat, 26 Jun 2010 03:09:19 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-32142 Sorry Krishna, I mistake. It is digital modulation block (QAM). Thanks Krishna! Sorry Krishna, I mistake. It is digital modulation block (QAM).
Thanks Krishna!

]]> By: Krishna Sankar http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31720 Krishna Sankar Mon, 21 Jun 2010 00:51:48 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31720 @dungpt: Your numbers are right. You can assume that the sampling period is the sampling period of the FFT. Sampling period of DAC need not be sampling period of iFFT. Typically, DAC can have 2x/3x oversampling compared to fft sampling rate. @dungpt: Your numbers are right. You can assume that the sampling period is the sampling period of the FFT. Sampling period of DAC need not be sampling period of iFFT. Typically, DAC can have 2x/3x oversampling compared to fft sampling rate.

]]> By: Krishna Sankar http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31719 Krishna Sankar Mon, 21 Jun 2010 00:49:15 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31719 @thieutuoc: What is mass mapping? Are you referring to QAM mapping? @thieutuoc: What is mass mapping? Are you referring to QAM mapping?

]]> By: Krishna Sankar http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31713 Krishna Sankar Mon, 21 Jun 2010 00:43:19 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31713 @thieutuoc: Sorry, I do not follow your query. @thieutuoc: Sorry, I do not follow your query.

]]> By: thieutuoc http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31403 thieutuoc Tue, 15 Jun 2010 00:09:37 +0000 http://www.dsplog.com/2008/02/03/understanding-an-ofdm-transmission/#comment-31403 Hi krishna In OFDM system is a mapping blocks, data blocks will be put back into the IFFT, so the question is which blocks any effect? thank you! Hi krishna
In OFDM system is a mapping blocks, data blocks will be put back into the IFFT, so the question is which blocks any effect?
thank you!

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