计算可见光通信OOK调制方式的BER matlab

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q=1.6e-19;
% Charge of Electron
Ib=202e-6;
% Background Noise Current+interfernce
N0=2*q*Ib;
% Noise Spectral Density 2*q*Ib
Rb=1e6;
% bit rate.
Tb=1/Rb;
% bit duration
R=1;
% Receiver responsivity.
sig_length=1e5;
% No. of bits in the input OOK symbols.
snr_dB=0:9;
% signal-to-noise ratio in dB.
SNR=10.^（snr_dB./10）;
% signal-to-noise ratio
for i=1:length（snr_dB）
P_avg（i）=sqrt（N0*Rb*SNR（i）/（2*R^2））;
% average optical power
i_peak（i）=2*R*P_avg（i）;
% peak photocurrent
Ep（i）=i_peak（i）^2*Tb;
% Peak Energy
sgma（i）=sqrt（N0*Ep（i）/2）;
% sigma standard deviation