Comments on: Symbol Error Rate (SER) for QPSK (4-QAM) modulation http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/ Signal Processing for Communication Thu, 04 Mar 2010 16:31:39 +0530 http://wordpress.org/?v=2.8.4 hourly 1 By: amira http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-18717 amira Sat, 30 Jan 2010 03:24:10 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-18717 hi, i have three questions; the first one is the (sigma)^2=N/2 for the gaussian distribution, if it was just N what to change in the program; the second one is if your y (received signal) was not= x (signal)+w(noise) but y=hx+w with h is a complex vector how to change in the program; the last one we want to do the same thing calculating the error but this time using MMSE(minimum mean square error in order of SNR), what to do; Thanks a lot; hi,
i have three questions;
the first one is the (sigma)^2=N/2 for the gaussian distribution, if it was just N what to change in the program;

the second one is if your y (received signal) was not= x (signal)+w(noise) but y=hx+w with h is a complex vector how to change in the program;

the last one we want to do the same thing calculating the error but this time using MMSE(minimum mean square error in order of SNR), what to do;

Thanks a lot;

]]> By: samta rangare http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-17998 samta rangare Mon, 11 Jan 2010 05:48:09 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-17998 hi krishna.. u explained the relation b/w SNR and symbol error rate for QPSK,but if i want to get the relation b/e SNR and BER then what shoul i do n how do i proceed.In your another post u gave one relation between bit error and symbol error Pb~Ps/k. can i use it directly in case of qpsk. pls let me know thanks. hi krishna..
u explained the relation b/w SNR and symbol error rate for QPSK,but if i want to get the relation b/e SNR and BER then what shoul i do n how do i proceed.In your another post u gave one relation between bit error and symbol error Pb~Ps/k.
can i use it directly in case of qpsk.
pls let me know
thanks.

]]> By: Krishna Sankar http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-16669 Krishna Sankar Sun, 06 Dec 2009 23:29:06 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-16669 @thanesh: Hope you have finished the project by now. Changing the BPSK in OFDM to QPSK in OFDM case should have been reasonably straightforward. a) BER for BPSK with OFDM in AWGN http://www.dsplog.com/2008/06/10/ofdm-bpsk-bit-error/ b) BER for BPSK with OFDM in 10 tap multipath channel http://www.dsplog.com/2008/08/26/ofdm-rayleigh-channel-ber-bpsk/ @thanesh: Hope you have finished the project by now. Changing the BPSK in OFDM to QPSK in OFDM case should have been reasonably straightforward.
a) BER for BPSK with OFDM in AWGN
http://www.dsplog.com/2008/06/10/ofdm-bpsk-bit-error/
b) BER for BPSK with OFDM in 10 tap multipath channel
http://www.dsplog.com/2008/08/26/ofdm-rayleigh-channel-ber-bpsk/

]]> By: Krishna Sankar http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-16668 Krishna Sankar Sun, 06 Dec 2009 23:27:36 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-16668 @Kishore: My replies 1) Try using randsrc() from http://octave.sourceforge.net/doc/f/randsrc.html 2) Unit energy is to ensure that we do a fair comparison when comparing different modulation techniques. Also, in typical transmitters, we do not want the power to jump when we change modulation schemes. So, we normalize the baseband transmission path to unity. @Kishore: My replies
1) Try using randsrc() from http://octave.sourceforge.net/doc/f/randsrc.html
2) Unit energy is to ensure that we do a fair comparison when comparing different modulation techniques. Also, in typical transmitters, we do not want the power to jump when we change modulation schemes. So, we normalize the baseband transmission path to unity.

]]> By: thanesh http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15995 thanesh Wed, 25 Nov 2009 02:55:17 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15995 Hi Krishna i was trying to simulate qpsk in ofdm like the one you did for bpsk in ofdm. could you please help me. and also Rician channel as well , this for my project .could u help me please.asap thanks regards thanesh Hi Krishna
i was trying to simulate qpsk in ofdm like the one you did for bpsk in ofdm. could you please help me. and also Rician channel as well , this for my project .could u help me please.asap
thanks
regards
thanesh

]]> By: Kishore http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15990 Kishore Wed, 25 Nov 2009 00:02:48 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15990 Hello Krishna, 1) how can i generate source symbols of the following constellation ( 1,0) ,(0,sqrt(3), (-1,0) and ( 0,-sqrt(3)). in matlab using randn. I tried randsrc() but it did not help 2) It is necessary to have unit enery( normalized variance =1) for the generated symbols? What is the reason.? Could you pls reply, Thanks, Kishore. Hello Krishna,

1) how can i generate source symbols of the following constellation
( 1,0) ,(0,sqrt(3), (-1,0) and ( 0,-sqrt(3)). in matlab using randn.
I tried randsrc() but it did not help

2) It is necessary to have unit enery( normalized variance =1) for the generated symbols? What is the reason.?

Could you pls reply,
Thanks,
Kishore.

]]> By: Krishna Sankar http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15139 Krishna Sankar Sun, 08 Nov 2009 02:45:37 +0000 http://www.dsplog.com/2007/11/06/symbol-error-rate-for-4-qam/#comment-15139 @dhanabalu: Thanks @dhanabalu: Thanks

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