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31 Threads found on Frequency Domain Equalization
frequency domain equalization is said to be less computationally complex as compared to time domain equalization why? where can I find the analysis? could you send mail me the paper
HI guys, can someone give me brief explanation about time domain equalization and how different it is from frequency domain equalization, also I would appreciate if you guys could help me with some matlab codes to start working on this area thnk u in advance
Hi, I am reading a paper on equalization on frequency domain, and the author says that to convert the MMSE in the time domain we need first to expand the transmitted sequence and the equalizer coefficients from say M samples to some N>=2M-1 samples by padding zeros. Why is that? Thanks
Time domain equalization is done by using "all pass networks." These are a quad of two left half plane poles and two right hand plane zeros. (You can also use a real LHP pole and RHP zero pair for frequencies near DC.) These produce a time delay near the pole frequency without any amplitude changes. You adjust the real and imaginary (...)
Hi can any one help me to simulate a iterative(turbo) frequency domain equalization? its diagram and paper has attached. my essential problem is MAP decoder and the relationship between SNR andBER. Thanks. Excuseme the site for download the paper is
what is equalization? why it is needed ? what is timedomain and frequency domain equalization?
Hi, It is know that the ISI can be compensated by a time-domain channel equalizer--a linear transversal filter. From the following paper, tt is said that "the number of adaptive tap coefficients is on the order of the number of data symbols spanned by the multipath". For ex, If RMS delay spread=10us data rate=1MHz Then number of taps=1
I am simulating an adaptive channel estimator for MIMO single carrier frequency domain equalization with space time block coding. I need to design the Training sequence. I am using QPSK modulation. I have read that Frank Zadoff sequence are optimal for training sequence. could anybody tell me how to generate Frank Zadoff unique word sequence (...)
Hi please help me to simulate a frequency domain turbo(iterative) equalization. its diagram has attached. my essential problem is MAP decoder and the relationship between SNR and BER. you can download its paper for better intuition and equations from this site if any one help me I will
this may be of some help of course this is for the frequency domain Equalizer in Simulink, but still you will get an idea of what they do.
I want good quality video lectures on equalization like LMS, RLS, frequency domain equalization. Ideally the lectures should be with a digital pen as it is clearer than a person writing on the board. But please send me the links at communications (under-score) engineer (at) Yahoo (dot) com
I want good quality video lectures on equalization like LMS, RLS, frequency domain equalization. Ideally the lectures should be with a digital pen as it is clearer than a person writing on the board. But please send me the links at communications (under-score) engineer (at) Yahoo (dot) com
Hello, I am simulating OFDM transmission over a Fading Channel in Matlab (using the 2009a version) at my university I am concatenating 100 OFDM symbols, where one symbol has 80 samples (64 subcarriers and 16 cyclic prefix). I create a Rayleigh fading channel object and filter my serial stream of OFDM symbols with the fading channel. No
There is no fundamental difference. I suppose the term equalizer traditionally means "making frequencies equal." In order to estimate a distorted signal, that is exactly what you have to do. On the other hand, the term is now also being used in the context of non-stationary signals, where a frequency domain interpretation is not strictly possibl
this is my mmse code,could some how help me?it doesn't work. i have my pdp and its length is L. SNR = 1/(noiseVar); beta=1; power_delay_profile=; power_delay_profile=fft(power_delay_profile); power_delay_profile=diag(power_delay_profile(carriers)); % Calculate frequency correlation matrix R_hh
Hi guys, I am working on optical ofdm, its not much of a different from normal ofdm. I have a problem at the receiver side where my constellation shifts in phase. So I did a very simple equalization, where the data before IFFT which will be in so call frequency domain, assume that as X. Then the data at receiver after FFT which wi
Hi kalyanasv , Thank you for your reply, concerning passing the data through teh channel, i have used 4QAM to modulate the data, and i know after this step comes pilot insertion-IFFT -CP then transmission through channel afterwards the reverse process (remove CP-FFT- remove pilots ), only i have read somewhere, i dunnot remember where tough taht,
Ok, but the two sequences do not have to be of equal size, right? I am reading papers about single-carrier frequency domain equalization (SC-FDE), and some papers padding zeros to the to the input sequence, while others appending to the front of the sequence the last part of it (this is called cyclic prefix) to make the linear convolution (...)
Hello, does anyone has a MATLAB code for single-carrier frequency-domain equalization (SC-FDE) for the simple linear case? Thanks in advance
Hello all, I am working on sparse channels with frequency domain equalization (FDE), where the transmission is block-based, which is very similar in structure to OFDM, where each frame begins with a CP. The problem in sparse channels is that the channel impulse response (CIR) is very long, while just a small number of taps are non-zero. (...)
Hello all, Can I ask you guys how to come up with something novel? Suppose you are working on a certain framework like frequency selective channels and single carrier frequency domain equalization (SC-FDE), then what? Thanks
Hi, Can any one explain ISI in frequency domain? Thanks in advnace
Hello, I have an OFDM system over a time varying frequency selective channel, which means I have ICI at the receiver side. I am dealing with the ICI using linear frequency equalizer like MMSE. Without ICI equalization, there is an error floor in the ABER vs. SNR. With ICI equalization, the curve decays well until a (...)
I think for 802.11b, a decision feedback equalizer is used for channel equalization, as for 802.11a/g, one-tap equalization in frequency domain is good enough since it's OFDM-based.
Hi, Do you want to use it for signal detection/equalization in fading channel? If yes for what kind of channel (I mean frequency selective/time varying or what?) state space equations depend on kind of application you want. so for different scenarios state space equation differ? regards
gmsk modulation of numerical data generated by a random source, the output of the modulator give two signals, only for demonstration, the first is gmsk signal and the other is gaussien frequency pulse shape
Hello, can you please help me in understanding the following lines taken from the book "Fundamentals of Wireless Communication" by David Tse & Pramod Viswanath. I quote section 3.4.4, page number 95 ------------------------------------------------------------------------------------------------- Both the single-carrier system with ISI equ
FFT (Fast Fourier Transform) is a method that calculates the Fourier transform of a signal which is in time domain. Normally we are accustomed to view a signal in time domain (x-axis being time and y-axis being amplitude). Fourier transform enables us to view the signal in frequency domain. Why do we need to see a (...)
Gram-Schmidt Orthonormalization procedure takes a set of linearly independent non-orthogonal vectors and represents them over a set of orthogonal basis functions with weights. In the receiver side, if we know the orthonormal basis functions then it will be easier to detect the received vector (by using a correlation demodulator). It is used to
Hello, I am implementing OFDM in frequency domain and run it under multipath fading, and to mitigate the effect of multipath I have done channel correction by multiplying the received signal by the phase of channel response (h). But that not enough to reduce the MP effect I need 1-tap equalizer: I read some where I need to insert pilot then I can
Bandwidth is reduced due to overlapping spectra of different subcarriers in frequency domain. Regarding BER, in AWGN, you'll find that the BER is nearly the same but in fading channels, it depends on the equalization technique you're using.