%%?This?programe?provides?SER?analysis?of?amplify?and?forward?cooperative?protocol?using?QPSK?modulation%%%
%%?Results?are?compared?with?theoratical?results?for?QPSK?modulation?with?AWGN?and?Rayleigh?fading?channels?%%%
clear?all
clc
N=?10^6;?%number?of?symbols
Pt=1;%?Total?Tranmited?Power
Pb=Pt/2;%?Transmitted?power?of?source
Pr=Pt/2;?%?Transmitted?power?of?Relay
snr_db=[0:40];%?SNR?in?dB
data_BS1?=?（（2*（rand（1N）>0.5）-1）?+?j*（2*（rand（1N）>0.5）-1））%%?Data?generation
data=zeros（1N）;?%?Received?data?matrix

%%?Channel?gains
????????channel_BS1_RS1=（1/sqrt（2））.*[randn（1N）+j*randn（1N）];%?Channel?coefficients?for?Soure-Relay?link
????????a11=sum（（abs（channel_BS1_RS1）））/N;?%Average?channel?gain?for?Soure-Relay?link?Channel
????????????????
????????channel_RS1_MS1=（1/sqrt（2））.*[randn（1N）+j*randn（1N）];%?Channel?coefficients?for?Relay-Desination?link
????????b11=sum（（abs（channel_RS1_MS1）））/N;?%Average?channel?gain?for?Relay-Desination?link?Channel
????????????????
????????channel_BS1_MS1=（1/sqrt（2））*[randn（1N）+j*randn（1N）];%?Channel?coefficients?for?Soure-Desination?Direct?link
????????c11=sum（（abs（channel_BS1_MS1）））/N;?%Average?channel?gain?for?Soure-Desination?link?Channel
?%%?AWGN?????
????????nbr=（1/sqrt（2））.*（randn（1N）+j*randn（1N））;%AWGN?for?at?Relay?for?Soure-Relay?link
????????nrm=（1/sqrt（2））.*（randn（1N）+j*randn（1N））;%AWGN?for?at?Desination??for?Relay-Desination?link
????????nbm=（1/sqrt（2））.*（randn（1N）+j*randn（1N））;%AWGN?for?at?Desination??for?source-Desination?link
????????
for???????i=1:length（snr_db）
????????????????snr_linear（i）=10.^（snr_db（i）/10）;???%?Linear?value?of?SNR???????????????????????????
????????????????No（i）=Pt./snr_linear（i）;????????????%?Noise?power
?????????????????
???%%?AMPLIFICATION?FACTOR
???????????????Beta1=sqrt（Pr./（a11^2.*Pb+No（i）））;
??????????????????????????????
???%%?RECEIVED?DATA?AT?RELAY?FROM?BS?????????
???????????????data_BS1_RS1=sqrt（Pb/2）.*data_BS1.*channel_BS1_RS1+sqrt（No（i））*nbr;
????????????????????????????
???%%?RECEIVED?DATA?AT?MS?FROM?RS?