pts-papr.m

clip&Filter,PTS和SLM三种降低PAPR的方法以及其优化算法

% PTS--PAPR Simulation
%
% Reference: S. H. Müller and J. B. Huber, “OFDM with Reduced
% Peak–to–Average Power Ratio by Optimum Combination
% of Partial Transmit Sequences,” Elect. Lett., vol. 33,
% no. 5, Feb. 1997, pp. 368–69.%
% 
% Author: Bin Jiang
% National Mobile Communication Research Laboratory
% Southeast University, 210096 Nanjing, China
% Email: [e-mail]
clear all;
clc; 
close all;

K = 128;                                                                    % SIZE OF FFT 
V = 4;                                                                       % NUMBER OF SELECTIONS
QPSK_Set  = [1 -1 j -j];
Phase_Set = [1 -1];

Choose = [1 1 1 1; 1 1 1 2; 1 1 2 1; 1 2 1 1; 2 1 1 1;
          1 1 2 2; 1 2 1 2; 1 2 2 1; 2 2 1 1; 2 1 2 1; 2 1 1 2;
          2 2 2 1; 2 2 1 2; 2 1 2 2; 1 2 2 2; 2 2 2 2];
Choose_Len = 16;      

MAX_SYMBOLS  = 1e4;
PAPR_Orignal = zeros(1,MAX_SYMBOLS);
PAPR_PTS     = zeros(1,MAX_SYMBOLS);

for nSymbol=1:MAX_SYMBOLS
    Index = randint(1,K,length(QPSK_Set))+1;
    X = QPSK_Set(Index(1,:));                                               % Orignal Frequency domain signal
    x = ifft(X,[],2);                                                       % Time domain signal
    Signal_Power = abs(x.^2);
    Peak_Power   = max(Signal_Power,[],2);
    Mean_Power   = mean(Signal_Power,2);
    PAPR_Orignal(nSymbol) = 10*log10(Peak_Power./Mean_Power);
    
    % PTS 
    A = zeros(V,K);
    for v=1:V
        A(v,v:V:K) = X(v:V:K);
    end
    a = ifft(A,[],2);
    
    min_value = 10;
    for n=1:Choose_Len
        temp_phase = Phase_Set(Choose(n,:)).';
        temp_max = max(abs(sum(a.*repmat(temp_phase,1,K))));
        if temp_max<min_value
            min_value = temp_max;
            Best_n = n;
        end
    end
    aa = sum(a.*repmat(Phase_Set(Choose(Best_n,:)).',1,K));
        
    Signal_Power = abs(aa.^2);
    Peak_Power   = max(Signal_Power,[],2);
    Mean_Power   = mean(Signal_Power,2);
    PAPR_PTS(nSymbol) = 10*log10(Peak_Power./Mean_Power);
    
end

[cdf1, PAPR1] = ecdf(PAPR_Orignal);
[cdf2, PAPR2] = ecdf(PAPR_PTS);

%--------------------------------------------------------------------------
semilogy(PAPR1,1-cdf1,'-b',PAPR2,1-cdf2,'-r')
legend('Orignal','PTS')
title('V=4')
xlabel('PAPR0 [dB]');
ylabel('CCDF (Pr[PAPR>PAPR0])');
grid on


%这个程序通用性不好，仅供参考。给出的程序中V=4，仿真其他情况需要修改Choose这个集合的元素.
%可以等间隔地选取部分点来画曲线
%比如：
%semilogy(PAPR1,1-cdf1,'-b'）
%可改为:
%semilogy(PAPR1(1:4:end), 1-cdf1(1:4:end), '-bo')
%中间的间隔可以根据实际绘图效果来确定
% PTS 相邻分割
%A = zeros(V,K);
%for v=1:V
%    A(v,v:V:K) = X(v:V:K);
%end
%a = ifft(A,[],2);
% 注：（1） 上面的代码没有要求K/V是整数

%若采用随机分割，可用下述代码描述:

%Index= randperm(K);
%A = zeros(V,K);
%for v=1:V
%    A(v,Index(v:V:K)) = X(Index(v:V:K));
%end
%a = ifft(A,[],2);
% 注：Index是1：K的随机置换后的序列，对Index的可以进行任意分割，上面的代码仍采用等间隔分割