papr_analysis.asv

OFDM峰均比经典算法matlab程序

clear all
clc
hold on

%Parameter setting
fftn = 128;  %FFT点数
CP_length = fftn/8; %循环前缀长度
symbol_num = 1e2; %OFDM符号数
M = 1;      %调制阶数（1——BPSK）?????????
data_length = fftn*symbol_num*M;  %数据长度

%Data generating
data_source = bingen(data_length);

%OFDM modulate
data4ifft = reshape(data_source,fftn,symbol_num);  %S/P

ifft_out = sqrt(fftn)*ifft(data4ifft);   %ifft  为什么求iff的sqrt???
ifft_out_temp1 = ifft_out;

        %%%%%%%% PAR Control %%%%%%%%%%%
%         限幅
        MaxPAR = 3; %dB,PAR门限
        for ii = 1:symbol_num
            xn = ifft_out(:,ii);
            arverage_pwr = norm(xn)^2/fftn;
            for kk = 1:fftn
                if (abs(xn(kk)))^2/arverage_pwr > 10^(MaxPAR/10)%??????????
                    xn(kk) = xn(kk)*sqrt(10^(MaxPAR/10)*arverage_pwr)/abs(xn(kk));%??????????
                end
                ifft_out(kk,ii) = xn(kk);
            end
        end
         
         %压缩扩展变换
%          u = 3; %变换因子
%          A = max(max(abs(ifft_out)));
%          for ii = 1:symbol_num
%              xn = ifft_out(:,ii);
%              av_p = xn'*xn/fftn;
%              for kk = 1:fftn
%                  temp = ifft_out(kk,ii);
%                  ifft_out(kk,ii) = A*temp*log(1+u*abs(temp)/A)/(log(1+u)*abs(temp));
%              end
%              av_p1 = ifft_out(:,ii)'*ifft_out(:,ii)/fftn;
%              ifft_out(:,ii) = av_p*ifft_out(:,ii)/av_p1;
%          end
         
         %CCDF计算
         plotPAPR = zeros(1,symbol_num);
         for ii = 1:symbol_num
             xn1 = ifft_out(:,ii);
             arverage_pwr = xn1'*xn1/fftn;%(平均功率是这样计算的：求每一个样值的功率在求和然后求平均)
             max_value = max(abs(xn1));
             PAPR = max_value^2/arverage_pwr;%计算发送信号的PAPR及平均功率
             plotPAPR(ii) = 10*log10(PAPR);
         end
         
         CCDF = zeros(1,13);
         for jj = 1:13
             PAR_temp = zeros(1,symbol_num);
             PAR_temp(find(plotPAPR > jj-1)) = 1;%??????????
             CCDF(jj) = sum(PAR_temp)/symbol_num;
         end
         PAR_max = 0:1:12;%(门限值)
         semilogy(PAR_max,CCDF,'g+-')
         grid on
         
% %Add CP
% 
% %P/S
% s = reshape(ifft_out,size(data_source));
% 
% %Transmit
% EbNo = 0:1:10;
% No = 1;
% noise = sqrt(1/2)*(randn(1,data_length)+1i*randn(1,data_length));
% error = zeros(1,length(EbNo));
% for E_N = 1:length(EbNo)
%     Eb = No*10^(EbNo(E_N)/10);
%     s_tr = sqrt(Eb)*s;
% 
% %AWGN channel
%     
% %Receive
%     s_re = s_tr+noise;
%     
% %Remove CP
%     
% %OFDM demodulate
%     data4fft = reshape(s_re,size(data4ifft));  %S/P
%     
%     fft_out = fft(data4fft)/sqrt(fftn);  %FFT
%     
%     data2decid = reshape(fft_out,size(data_source));
% 
% %Decide
%     data_receive(find(real(data2decid) < 0)) = -1;
%     data_receive(find(real(data2decid) >= 0)) = 1;
%     
%     error(1,E_N) = (sum(abs(data_receive-data_source))/2)/data_length;
% end
% 
% semilogy(EbNo,error,'mx-')