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05 Oct 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	Shanar	Hi Mate This is really good work just I have simple question in my mind, can i emplement your code to work on IEEE802.16 transmitter receiver? Thanks in advance
04 Apr 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	Krishna Sankar M	@Yi Xiao: The channel power is indeed the scaling factor, no?
02 Apr 2009	Simulating CDF of Peak to Average Power Ratio for OFDM Obtain the CDF plots of PAPR from an OFDM BPSK transmission specified per IEEE 802.11a specification Author: Krishna Sankar M	Zhong
26 Mar 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	PRAVEENA
21 Mar 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	Xiao, Yi	Thank u, it helps a lot. By the way, could u please recommend me some paper or articles that talk about the scaling factor problem for Alamouti's code in higher order modulation? I am studing on Alamouti's paper and I can get the same simulation result when using BPSK but not for QPSK, ur code inspires me alot and I want to learn more about scaling factor u mentioned. Thanks again.
21 Mar 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	Krishna Sankar M	@Yi Xiao: Well, for BPSK constellation, you are right - one need not divide by the channel power. However, for higher order modulations one needs to take care of the scaling factor such that the constellation boundaries can be defined correctly. Hence provided the equation for the general case. Hope this helps.
18 Mar 2009	Alamouti STBC Discuss 2Tx. 1Rx transmit diversity scheme called Alamouti Space Time Block Coding (STBC) Author: Krishna Sankar M	Xiao, Yi	Very good! Clear codes and explanation. Only one question, why we need these lines: yHat = sum(hEq.yMod,1)./hEqPower; yHat(2:2:end) = conj(yHat(2:2:end)); I mean, if the decision rule is: ipHat = real(yHat)>0; Then yHat = sum(hEq.yMod,1) will be enough for everything. Why do we need to divide it by the power of the channel and do the conjugate for h2y1 -h1y2 ? I am a little bit confused here.
31 Dec 2008	MIMO with Zero Forcing equalizer Describes a 2x2 MIMO system using Zero Forcing equalizer in Rayleigh fading channel. Author: Krishna Sankar M	bc, nintendo
23 Aug 2008	16QAM BER with Gray Mapping Derive the theoretical 16QAM bit error rate (BER) with Gray coded constellation mapping in AWGN Author: Krishna Sankar M	Pillai, Krishna	@Paul: Thanks for the comment. Sure, I can add link to your code (with credits) in www.dsplog.com. However, I would like to understand the equation prior. For a general M-QAM (M-even), the symbol error rate has an erfc() term and erfc^2() term. uri: http://www.dsplog.com/2008/05/24/article-in-dspdesignlinecom-m-qam-symbol-error/ And for ber, I just took the first term. Given the above understanding, I was unable to understand the equation which you have suggested. How have you converted the erfc^2() term to two erfc() terms? Kindly point me to a reference, if possible. Thanks in advance. Warm regards, Krishna
21 Aug 2008	16QAM BER with Gray Mapping Derive the theoretical 16QAM bit error rate (BER) with Gray coded constellation mapping in AWGN Author: Krishna Sankar M	Buné, Paul A.M.	Excellent tutorial. However, please be aware that the theoretical 16QAM BER as used in this program BER=(3/8)erfc(sqrt(0.4Eb_N0)) is just an (albeit good) approximation, as you already indicated in your www.dsplog.com post. The exact Gray-mapped 16QAM BER with AWGN is BER=(3/8)erfc(sqrt(0.4Eb_N0))+(1/4)erfc(3sqrt(0.4Eb_N0))-(1/8)erfc(5sqrt(0.4Eb_N0)) as generated by entry nr. 19717 in the Mathworks File Exchange. The difference between the approximate theoretical BER and the exact BER gets significant for Eb/N0 below 0dB, being 27% at Eb/N0=-10dB and growing to 33% for Eb/N0=0 (or minus infinity in dB). The simulated 16QAM BER can be shown to deviate clearly from the approximate theoretical BER for Eb/N0<0dB, while it closely follows the exact theoretical BER for all values of Eb/N0. Entry 19717 also produces exact BER values for Gray-mapped QPSK, 256QAM etc. and, further to over-all BER values, it also generates the different BER values for the different bit positions in 16QAM, 256QAM etc. On the condition that the origin is clearly indicated, please feel free to use my entry nr. 19717 and its results on your site http://www.dsplog.com/. Paul A.M. Buné
15 Aug 2008	BER for BPSK in Rayleigh channel Simulates the BER for BPSK modulation in Rayleigh channel Author: Krishna Sankar M	Random, R	@Pillai. I have to admit that you're right. What I forgot is the fact that the additive noise is also divided by the channel.
15 Aug 2008	BER for BPSK in Rayleigh channel Simulates the BER for BPSK modulation in Rayleigh channel Author: Krishna Sankar M	Pillai, Krishna	@random: May I suggest that your observation is incorrect. Even when we know the channel, and divide the received symbol by the known channel, the resultant noise term is no longer white. Hence it is not comparable to AWGN channel. Further, in the Matlab code the BER obtained from simulations are shown to be matching the theoretically expected results.
14 Aug 2008	BER for BPSK in Rayleigh channel Simulates the BER for BPSK modulation in Rayleigh channel Author: Krishna Sankar M	Random, R	Once you divide the received signal by the known channel you have removed the impact of the channel totally. In other words, it is the same as an AWGN channel, and there is no fading in the model.
19 Jun 2008	spectrum of an OFDM transmit A simple Matlab script where a BPSK modulated signal is transmitted on the 52 used subcarriers, loos Author: Krishna Sankar M	kool, koolbone
19 Jun 2008	Simulating CDF of Peak to Average Power Ratio for OFDM Obtain the CDF plots of PAPR from an OFDM BPSK transmission specified per IEEE 802.11a specification Author: Krishna Sankar M	rajakani, Kalidoss	good effort sir........
14 May 2008	Simulation of an MSK transmission Generates an MSK transmission Author: Krishna Sankar M	ider, ziya	excellent
04 May 2008	Symbol Error Rate in 4-PAM modulation The script computes the symbol error rate for 4PAM modulation Author: Krishna Sankar M	mahakam, chagrapong
20 Apr 2008	QPSK (4QAM) symbol error rate Simulates the symbol error rate for QPSK modulation scheme Author: Krishna Sankar M	dhf, dhf	hdf
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