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From: mahmud_dbm on 14 Feb 2010 09:53
Sir and one more thing, if i would have used wavedec, which returns the decomposition structure and coefficients, with the low- and high-pass decomposition filters you specify and i'm getting coefficients there and i am able to reconstruct my signal, no problem with that.. so i need to have the same kind of coefficients for packet too, to reconstruct,

or i should ask you the difference between wavedec and wpdec.. i couldn't understand from doc help... :((
From: Wayne King on 14 Feb 2010 11:00
"mahmud_dbm " <mahmud_dbm(a)yahoo.com> wrote in message <hl92oe$at7$1(a)fred.mathworks.com>...
> Sir and one more thing, if i would have used wavedec, which returns the decomposition structure and coefficients, with the low- and high-pass decomposition filters you specify and i'm getting coefficients there and i am able to reconstruct my signal, no problem with that.. so i need to have the same kind of coefficients for packet too, to reconstruct,
>
> or i should ask you the difference between wavedec and wpdec.. i couldn't understand from doc help... :((

wavedec gives you a wavelet decomposition, where only the lowpass output is subdivided further into low and high pass parts. A wavelet packet decomposition divides both the lowpass and highpass outputs at each resolution level. You can use wprec() to reconstruct your signal For example:

% Create a wavelet packets tree.
x = rand(1,512);
t = wpdec(x,3,'db3');
t = wpjoin(t,[4;5]);

% Write values.
sNod = read(t,'sizes',[4,5]);
cfs4 = zeros(sNod(1,:));
cfs5 = zeros(sNod(2,:));
t = write(t,'cfs',4,cfs4,'cfs',5,cfs5);
% reconstruct signal with two nodes zero-ed out.
y = wprec(t);

Wayne
From: mahmud_dbm on 15 Feb 2010 01:24
Dear Sir, Thank you once again to be with me,

Sir, what i am planning to do is, i will have these 512 binary Bits at Transmitter and will pass them through any channel, at the Receiver i will reconstruct them.. this is all i'm planning to do.

from Tx output.. i cant send This "Tree" over any channel, so i need to have the total coefficients of all the nodes of final level decomposition.
(like we get a single coeff sequence using wavedec)

> % Create a wavelet packets tree.
> x = rand(1,512);
> t = wpdec(x,3,'db3');
> t = wpjoin(t,[4;5]); % Still it is a Tree Sir.. :((

after decomposing where do i get all the coefficients of last level of decomposition, so that i can send them over any channel. I cant send any tree over any channel, say Awgn..

so i did something like this..

clear all;close all;clc
EbN0=1:10;

for i=1:length(EbN0)
ip = randint(1,128);
mbit=pskmod(ip,2);
T = wpdec(mbit,3,'db3');
T = wpjoin(T,[4;5]);

noise_bit=awgn(T,EbN0(i));

% This is an Error, because I Cant Pass This Tree here, i need to pass decomposed Hi & Low pass co-efficients only, and if wprec(T) requires a Tree to get the binary signal back then at the receiver end i need to reconstruct this Tree from Coefficients. not from the Tree we got from the Transmitter side itself, because we "couldn't transmit Tree through the channel"

% Write values.
sNod = read(T,'sizes',[4;5]);
cfs4 = zeros(sNod(1,:));
cfs5 = zeros(sNod(2,:));
T = write(T,'cfs',4,cfs4,'cfs',5,cfs5);
% reconstruct signal with two nodes zero-ed out.
y = wprec(T);
op=pskdemod(y,2);

[num ber(i)]=biterr(ip,op);
end

semilogy(EbN0, ber);
grid on;

I Guess i'm in Trouble, but using wavedec i could get the coefficients pretty easily like

ip = randint(1,128);
mbit=pskmod(ip,2); % Modulation

[wbit,l] = wavedec(mbit,2,'haar');
% Low pass Decomposition, and This wbit is Total Coefficients and we are allowed % to pass it through any channel. like

nbit=awgn(wbit,EbN0(i)); % Noise addition
rbit = waverec(nbit,l,'haar'); % Reconstruction using Coeff

% No Problem here..
Sir i tried to explain my problem my level best, Thank you.. to read this history..
now i hope you can solve it, as i know the problem and u know the solution to it.
From: mahmud_dbm on 15 Feb 2010 12:20
Dear Sir,

Can i use something like this, here i am getting the exact result, but i'm not sure if it is doing the same as i wanted..

ip = randint(1,512);
mbit=pskmod(ip,2);
T = wpdec(mbit,2,'haar');

% all the coeffs
cfs = read(T,'allcfs');

% cfs to tree
T2 = cfs2wpt('haar',N,tnodes(T),2,cfs);
rbit=wprec(T2);
dmod=pskdemod(rbit,2);

It is working fine, cudn't understand properly everything,
really thank you sir to be with me ..
From: Wayne King on 15 Feb 2010 14:07
"mahmud_dbm " <mahmud_dbm(a)yahoo.com> wrote in message <hlbvo4$o9h$1(a)fred.mathworks.com>...
> Dear Sir,
>
> Can i use something like this, here i am getting the exact result, but i'm not sure if it is doing the same as i wanted..
>
> ip = randint(1,512);
> mbit=pskmod(ip,2);
> T = wpdec(mbit,2,'haar');
>
> % all the coeffs
> cfs = read(T,'allcfs');
>
> % cfs to tree
> T2 = cfs2wpt('haar',N,tnodes(T),2,cfs);
> rbit=wprec(T2);
> dmod=pskdemod(rbit,2);
>
> It is working fine, cudn't understand properly everything,
> really thank you sir to be with me ..


Hi, yes, I told you several times, you have to use wprec() to reconstruct the signal from the WP transform.
Wayne
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