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Equalization in OFDM

Hi, I am implementing an equalization algorithm for OFDM system. For this, after calculating the channel taps, we need to divide the complex sub-carrier symbols with complex tap values. I was wondering this division takes too many cycles for the DSP implementations. So is there any way of doing eq...

Re: Channel Modelling

On Aug 22, 8:44=A0am, "cpshah99" wrote: > > Hi Julius > > Extremely sorry for not replying properly. > > As u had said to run with channel effect and 'no noise', and I did the > simulation, but still I am getting errors even at high SNRs. > > I think the adaptive equaliser is ...

Bidirectional equalization

Hello, I'm simulating a Decision Feedback Equalizer for MSK signal, using the well know LMS algorithm. In order to get better performance I tried to equalize each packet in two stages. The structure of the packet is as follows: [Payload1 TrainingSeq Payload2] Since the training sequence is pla...

Frequency /time domain equalization

Hello, I am doing simulation studies for frequency and time domain equalization. From the complexit point of view I completely agreed to the fact that frequency domain is better in the number of multiplications/additions. Regarding the performance (BER ) point of view I can see there...

adaptive precoding and pre-equalization

I was trying to search through literature in order to find advantages and disadvantages of adaptive pre-coding and pre-equalization over adaptive post-equalization. I failed. Can anyone point to a good reference. 2ndly on adaptive pre-equalization there are only three papers when we search ieee...

Why not fractional space spampling when frequency domain equalization?

as we all konw, fractional space(FS) spampling is robust to nonideal timing synchronization when we do time domain decision-feedback equalization. My question is: why no paper mentioned using FS frequency domain DFE equalization? at least till now I havenot read a paper confirm it. Any comment or re...

Ungerboeck metric for MLSE Equalizer

Hello. Who can give me some description about Ungerboeck MLSE equalizer? I use it for GSM burst equalization and get strange result - it works bad. BER is increased as comparision with no equalization. I estimate Channel Impulse Response and use it for signal reconstruction in eaualizer but it ...

Equalization using DFT

Hi, I'm wondering, if there is no problem in equalization with DFT. Simply window the source signal, DFT, mutliply each frequency bin by a real value defining it, and IDFT. This would even be zero-phase filtering wouldn't it? Or am I missing something? Thanks! dmnc ...

a question about the effect of channel estimation and equalization in ofdm

in OFDM systems, the LS channel estimation result should be H'=P'/P if we compensate the received data symbols with one tap scheme, the equalization result should be D''=D'/H' = P*D'/P'; one the right of the above equation, D'/P' looks like the differential decoding result so the cohe...

Equalization in satelleite channel

Does signal from geostationaric satellite need to be equalized? I'm talking about static receivers, not mobile. Because as far as I understand this channel, except for non-linear distorion due to high-power amplifiers, which does not affect M-PSK modulations, there are no other distortions that re...

Equalization without a training sequence

I have seen many IEEE papers on what is now called Blind Equalization where a PBRS sequence is not needed for training. This is for muliple- channel (multivariable) problems. A colleague of mine says this is just academic rubbish and not used in practice. true or false and if true would there be...

relationship between time/frequency offset compensation and channel equalization

Hi, All i am really confused of these two concept. time/frequency offset will cause signal distortion but this distortion can be recoverd by channel equalization. what's the difference between time/frequency offset compensation and channel equalization? Thank you! ...

Audio Equalization Using MDCT

I have done real-time audio equalization using fast-convolution (overlap-add) where the frequency domain values were specified by the end user through a graphical interface. If the phase response did not need to be specified, could a MDCT give better frequency resolution for around the same number ...

Q) MIMO-OFDM and freq-domain equalization

Hello, everyone. In SISO-OFDM, we usually employ a frequency domain equalization after the receiver FFT module, as a way to compensate for the channel distortion along frequency bins. We depend on OFDM channel estimation and simple inversion for this purpose. In MIMO-OFDM, either multiplexed s...

equalization of 'non-continuous' sample

I am trying to build a 'non-continuous' 12-tap FFE (LMS Blind) equalizer in software, hoping to remove to some extent group delay in a satellite link. I am doing in software, as I am ONLY keen to know the SNR after equalization. The reading are in chunks of 512 x I/Q samples. Technically, does t...

Turbo Equalization

Hi, I am working on Turbo Equalization based on MMSE-SC based techniques. I have a question on choosing the chnanel code. All papers which people refer uses convolutional codes decoded by using SOVA. Is there any reason why we use convolutional codes rather Turbo codes ? Any sugge...

IQ Receiver Processing

Can anyone please tell me one thing that in communication receiver, after performing matched filtering and timing recovery seperately for I and Q data, whether equalization works separately on I and Q data or we first get the complex signal (combining I and Q) and perform equalization on complex ...

Channel order and matrix state of viterbi equalization

Hi All, I am learning viterbi equalization to deal with ISI caused by multichannel effect. Let us denote L as the channel memory, that means we have L+1 channel taps. like this figure below. i.g. L=4 In --D--D--D--D-- | | | | | | | | | | h0 h1 h2 h3 h4 | |...

Equalization in OFDM

Hi guys, I was doing the simulations for the multitap frequency domain equalization for multicarrier system (DMT based). It seems though the at the band edges (First few tones and last few tones) higher performance can be achieved if we use higher number of equalizer taps. Can you people pl...

[Enquiry] how to add OFDM subcarriers in simulink

I am doing a project on OFDM equalization. So far, i have been doing equalization for one ofdm symbol. I wish to ask how could i add more subcarriers in by using Simulink? Is there any example that i can refer to? Thanks alot. ...

adaptive equalization benefit

How much benefit can adaptive equalization really get you in a packet transmission system over multipath channel? Since one will need to do synchronization before training the equalizer, it seems to me that synch will be the first one to fail most of the time if ISI is really serious. So that me...

ask help on viterbi equalization

Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What I learn from textbook, viterbi can handle bit sequence with some mistakes, and output correct bit sequence. How can it handle complex data inputs? Because...

Re: Software for isolation of specific frequencies

It sure seems to do what you want, but maybe you aren't looking for the right thing? The terms you want to look for are equalization and filtering. In Audacity, select your waveform, then go to Effects-> Equalization or Effects-> FFT Filter. -- Jon Harris SPAM blocker in place: Remove...

Wiener solution for equalization

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS algorithm? Will the result of the Wiener solution become better if I provide some delay to the desired signal? Thanks. ...

Turbo Equalization

I have the following outputs at the various iterations in Turbo Equalization. Iteration No. 1 -> Error at the output of BCJR = 16, Error at the output of ECC= 105 Iteration No. 2 -> Error at the output of BCJR = 8, Error at the output of ECC= 51 Iteration No. 3 -> Error at the output of B...

DPSK's relation with OFDM and Demodulation

Hi, I understand that simplified equalization is one of the good reasons for going with OFDM. But, how do they manage it ? That is, The OFDM may be viewed as using many slowly-modulated narrowband signals rather than one rapidly-modulated wideband signal. So, The Differential modulation such a...

Cable Equalizer

I'm looking for some inspiration on the following problem: I want to transmit a signal consisting of 8 QPSK-Modulated carriers over a coaxial cable, in the frequency range of 1 to 10 MHz. Since the cable has a frequency-dependent attenuation (e.g. 1dB/100m@1MHz, 3dB/ 100m@10 MHz), I need to so...

Re: psychoacoustics of audio effects (dsp), equalization and filtering

On 31 Gen, 14:00, "Setanta" wrote: > "different" wrote in message > > news:1170239891.106561.239840@j27g2000cwj.googlegroups.com... > > > I need to know what are the effects of sound alteration via dsp > > (reverb, echo, chorus, flanger...), filtering and equalization on > > p...

Re: Paper on LMS adaptive equalization

"Alberto" wrote in message news:wyQbf.28038$65.864605@twister1.libero.it... > I am in search of the PDF of this paper : > > "Efficient realization of asynchronous LMS adaptive equalization" > by Jan W.M. Bergmans > > I have been unable to find it with Google, nor to find an email ...

Re: Design of multirate filters

Do you perform an equalization on the data before plotting the constellation? JB. ...

Re: Deconvolution / Spectral division (Antenna)

Keyword: "equalization", for example Proakis, Digital Communications. ...

OFDM cyclic prefix/Equalization question

Hi, I am working on a uncode 16-QAM OFDM simulation. The simulation works fine when used in AWGN channel. I have a couple of questions now when i am simulating performance in multipath channels. 1) What I want to understand through simulation is the effect of cyclic prefix length on perform...

Re: Echo Cancellation - non acoustic application

> all: > > I dont know if this will work or not, but from what I read it sounds like > acoustic echo cancellation is fundamentally the same problem I have. > > I am recording pitch measurments with a single sensor located at the > center of gravity of a vehicle. I would like to extract the ...

classification under optimal and sub-optimal

well all dsp members, i want to clarify under what circumstances does the optimal and sub-optimal classifcations of a particular algorithm is done. we say EQUALIZATION with error control coding can be done in two ways 1. optimal receiver has to tackle out both I...

Re: Sliding window Viterbi

john wrote: ... > See if you can dig up a copy of "How I Learned to Love the Trellis" by > Bernard Sklar. It appeared in IEEE Signal Processing Magazine a couple > of years ago. If you can't find a copy, I'll send you one. The world fills me with awe. At 73, I am still amazed and th...

Re: Adaptive filtering

thom wrote: (top posting fixed) > > > Don't you think "I don't have information about the original signal" is > > rather incompatible with "it's a large band signal, ofdm modulation"? > > > > Steve > > > > > > Maybe I'm not clear... Yes I know for example the signal bandwidth...

Re: Channel tracking in an OFDM system

On Jul 28, 11:20 am, "ananth.rs" wrote: > Hello, > > I am trying to design an adaptive equalizer for an OFDM system which has > an extremely low symbol rate. I have a question regarding this. > > The transmitter and the receiver are moving wrt each other. For what > amount of relati...

Re: Question about aliasing spectrum in RC filter

Sorry, I had to add some information. The topic is about frequency domain equalization in broadband communication. It is an alternative to OFDM to deal with frequency selective fading channel. ...

MMSE & LMS Equalization Question

Ok so, i'm confusing myself somewhere and its driving myself crazy. I have written matlab implementations of MMSE (wiener) and LMS (gradient method .. h = h(n-1) + mu*dE/dh) to minimize the following equation: ( s[n] - yhat[n] )^2 where s[n] is the original 'sent' message and yhat[n]=conv(...

Re: lowpass tap count

I try to do a filter in practice. I know the influence of zeros and poles on the transfer function. I convert it into impulse response and convolve with it. Faced the need for large tap counts at low frequencies, I decided to ask if it is ok. BTW, if you know how to do equalization (combi...