Matlab clearly reports that the function qpskmod is not defined for arguments of
type double. I would have to look at your qpskmod function; matlab has a qpskmod
block in communication toolbox but no .m file, are you using the function block?
I guess that qpskmod expects an argument of type binary or string of 2 bits as
input argument.

-Amit Pathania

"n.mie_arul" wrote:

hi everyone..now i started my last year project about Rayleigh Fading

using OFDM system..i have a problem when using QPSK modulation..Below

is a my coding..anybody know how to solve this prob??

%******************* Preparation Part*****************************

para8; % Number of parallel channel to transmit

fftlen8; % FFT length

noc8; % Number of carrier

nd=6; % Number of information ODFM symbol for one loop

ml=2; % modulation level : QPSK

sr%0000; % symbol rate (kbps)

br=sr.*ml; % Bit rate per carrier

gilen2; % Length of guard interval (points)

ebn0; % Eb/No

%******************* Fading Initialization**************************

% if you use fading function "sefade", you can initialize all of the

% parameters.

%Otherwise you can comment out the following initialization.

tstp=1/sr/(fftlen+gilen); % Time resolution

%Arrival time for each multipath normalized bt tstp

%if you would like to simulate under 4 path fading model,we have only

to

%set direct wave.

itau = [0,2,3,4];

%Mean power for each multipath normalized by direct wave.

%If you would like to simulate under 4 path fading model,you have

only to

%set direct wave.

d1v1 = [0,10,20,25];

%Number of wave to generates fading for each multipath.

%In normal case,more than (minimun) six wave are needed to generates

Rayleigh fading

n0=[6,7,6,7];

%Initial phase of delayed wave

%In this simulation four path Rayleigh fading is considered.

th1=[0.0,0.0,0.0,0.0];

%Number of fading counter to skip

itnd0=nd*(fftlen+gilen)*10;

%Initial value of fading counter

%In this simulation four-path Rayleigh fading is considered.

%Therefore four fading counter is needed.

itnd1=[1000,2000,3000,4000];

%Number of direct wave + Number of delayed wave.

%In this simulation four-path Rayleigh fading is considered

now1=4;

%Maximum Doppler frequency [Hz]

%You can insert any favorite value.

fd20;

% you can decide two modes to simulate fading by changing the

variable flat

%flat : flat fading or not

%(1-flat (only amplitudes is fluctuated),0- normal (phase and

amplitude are

%flutuated))

flat=1;

%************************ main loop part****************************

nloopP0; % number of simulation loop

noe=0; % Number of error data

nod=0; % number of tranmitted data

eop=0; % number of error packet

nop=0; % number of tranmitted packet

for i = 1:nloop;

end

%************************ Tranmitter Stage***************************

%************************* Data Generation***************************

seldata=rand(1,para*nd*ml) > 0.5; % rand : built in function

%***********************Serial to parallel conversion*****************

paradata=reshape(seldata,para,nd*ml); % reshape : built in function

%************************* QPSK modulation****************************

[ich,qch] = qpskmod(paradata,para,nd,ml);

kmod=1/sqrt(2); % sqrt:built in function

ich1=ich.*kmod;

qch1=qch.*kmod;

the error displays '??? Undefined function or method 'qpskmod' for

input arguments of type 'double'.

Error in ==> psm at 93

[ich,qch]= qpskmod(paradata,para,nd,ml);'

how to solve this trouble?? i dont know how this meaning..tq

Amit Pathania