function?[pbps]=cm_sm32（snr_in_dB）
%?[pbps]=cm_sm32（snr_in_dB）
%????????????????CM_SM3?finds?the?probability?of?bit?error?and?symbol?error?for?
%????????????????the?given?value?of?snr_in_dB?signal?to?noise?ratio?in?dB.


N=100;
E=1;????????????????????????????????????????????%?energy?per?symbol
numofsymbolerror=0;
numofbiterror=0;
counter=0;
snr=10^（snr_in_dB/10）;??????????????????????????%?signal?to?noise?ratio
sgma=sqrt（E/snr）/2;?????????????????????????????%?noise?variance
s00=[1?0];?s01=[0?1];?s11=[-1?0];?s10=[0?-1];???%?signal?mapping
%?generation?of?the?data?source
while（numofbiterror<100）
for?i=1:N
????temp=rand;??????????????????????????????????%?a?uniform?random?variable?between?0?and?1
????if?（temp<0.25）?????????????????????????????%?with?probability?1/4?source?output?is?“00“
????????dsource1（i）=0;?dsource2（i）=0;
????elseif?（temp<0.5）??????????????????????????%?with?probability?1/4?source?output?is?“01“
????????dsource1（i）=0;?dsource2（i）=1;
????elseif?（temp<0.75）?????????????????????????%?with?probability?1/4?source?output?is?“10“
????????dsource1（i）=1;?dsource2（i）=0;
????else????????????????????????????????????????%?with?probability?1/4?source?output?is?“11“
????????dsource1（i）=1;?dsource2（i）=1;
????end;
end;
%?detection?and?the?probability?of?error?calculation

for?i=1:N
????ray=raylrnd（0.8）;
????n=sgma*randn（12）;??????????????????????????%?2?normal?distributed?r.v?with?0?variance?sgma
????if?（（dsource1（i）==0）?&?（dsource2（i）==0））?
????????r=ray*s00+n;
????elseif?（（dsource1（i）==0）?&?（dsource2（i）==1））?
????????r=ray*s01+n;
????elseif?（（dsource1（i）==1）?&?（dsource2（i）==0））?
????????r=s10*ray+n;
????else?
????????r=s11*ray+n;
????end;
????%?The?correlation?metrics?are?computed?below
????c00=dot（rs00）;?c01=dot（rs01）;?c10=dot（rs10）;?c11=dot（rs11）;
????%?The?decision?on?the?ith?symbol?is?made?next
????c_max=max（[c00c01c10c11]）;
????if?（c00==c_max）?decis1=0;?decis2=0;
????elseif?（c01==c_max）?decis1=0;?decis2=1;
????elseif?（c10==c_max）?decis1=1;?decis2=0;
????else?decis1=1;?decis2=1;
????end;
????%?Increment?the?error?counter?if?the?decision?is?not?correct
????symbolerror=0;
????if?（decis1~=dsource1（i））?numofbiterror=numofbiterror+1;?symbolerror=1;?
????end;
????if?（decis2~=dsource2（i））?numofbiterror=numofbiterror+1;?symbolerror=1;?
????end;
????if?（symbolerror==1）?numofsymbolerror=numofsymbolerror+1;?
????end;
????
end
counter=counter+1;
end
ps=numofsymbolerror/（N*counter）;??????????????????????????%?since?there?are?totally?N?symbols
pb=numofbiterror/（2*N*counter）;?????????????????????????%?since?2N?bits?are?transmitted?

?屬性????????????大小?????日期????時(shí)間???名稱
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?????文件???????2666??2013-06-17?08:58??基于matlab的QPSK系統(tǒng)仿真\cm_sm32.m

?????文件???????2695??2013-06-17?09:10??基于matlab的QPSK系統(tǒng)仿真\cm_sm33.m

?????文件???????9282??2013-06-17?08:56??基于matlab的QPSK系統(tǒng)仿真\qpsk.m

?????文件?????211770??2013-09-25?23:22??基于matlab的QPSK系統(tǒng)仿真\基于matlab的QPSK系統(tǒng)仿真.doc

?????目錄??????????0??2013-09-25?23:22??基于matlab的QPSK系統(tǒng)仿真

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???????????????226413????????????????????5