%function pb=multi_rayleigh_vita(Eb_to_Nj_in_dB,Eb_to_No_in_dB,BPH,number_of_states,Q) 
%VITERBI      This procedure simulates the Viterbi sequnce decoding of the
%             differential frequency hopping system
%
%             Eb_to_Nj_in_dB is the signal-to-jamming ratio given in dB
%
%             Eb_to_No_in_dB is the signal-to-noise ratio given in dB
%
%             BPH is the number of bits transmitted by one hop
%
%             number_of_states is the number of states in the DFH trellis,corresponding to the right L stages of the DFH encoding shift register 
%
%             Q is the number of jamming tones in the DFH bandwidth


%********系統(tǒng)參數(shù)********%
Eb_to_Nj_in_dB=[18];
Eb_to_No_in_dB=15;
BPH=2;
number_of_states=16;
Q=8; % 干擾音的個數(shù)
%************************%

N=100000; % 每次符號流長度
times=5; % 重復做50次
fanout=2^BPH; % DFH的扇出系數(shù)

vita_symbol_err=zeros(length(Eb_to_Nj_in_dB),times);% 維特比譯碼后符號錯誤計數(shù)器
num_of_err=zeros(length(Eb_to_Nj_in_dB),times);
% Ps=zeros(length(Eb_to_Nj_in_dB),1);
Pb=zeros(length(Eb_to_Nj_in_dB),1);

WTbarpp=waitbar(0,'Outer SNRs Loop:Please wait...');
for pp=1:length(Eb_to_Nj_in_dB)

Eb_to_Nj=10^(Eb_to_Nj_in_dB(pp)/10); % 比值形式的Eb/Nj
Eb_to_No=10^(Eb_to_No_in_dB/10); % 比值形式的Eb/No
L=floor(log(number_of_states)/log(fanout)); % 編碼移位寄存器的長度為L+1,最右邊L級是其狀態(tài)位,與網(wǎng)格圖中的狀態(tài)一一對應(注意并不是與跳頻頻點一一對應)

% pb=zeros(1,times);
WTbar=waitbar(0,'SNR inside loop:please wait...');
for rep=1:times

source=[randint(1,N,fanout),zeros(1,L)]; % 信息源:隨機符號流,最后補上L個0符號,使移位寄存器的狀態(tài)清零

%***********************信源部分************************%

% 將信息符號流轉化成二進制信息比特流,不包括最后補上的L個0符號(dsource只是在最后計算誤碼率的時候用)
dsource=zeros(1,N*BPH); 
if(BPH~=1)
    for i=1:N
        dsource((i-1)*BPH+1:i*BPH)=deci2change(source(i),BPH,2);
    end
else
    dsource=source(1:N);
end

%******************************************************%



% ******************* G 函數(shù)實現(xiàn)部分 ************************ %

% 先定義三個關鍵矩陣"nextstates" "output" "input"
nextstate=zeros(number_of_states,fanout); % nextstate矩陣:行代表網(wǎng)格圖中的各狀態(tài)(一一對應),列與輸入移位寄存器的信息符號一一對應,
                                          % 矩陣中存儲的內容是與當前狀態(tài)和輸入符號對應的下一狀態(tài)號(即存儲網(wǎng)格圖的狀態(tài)轉移規(guī)則)  
output=zeros(number_of_states,fanout);    % output矩陣:行代表網(wǎng)格圖中的各狀態(tài)(一一對應),列與輸入移位寄存器的信息符號一一對應,
                                          % 矩陣中存儲的內容是與當前狀態(tài)和輸入符號對應的網(wǎng)格圖分支轉移輸出(分支轉移輸出是跳頻頻率號)
input=zeros(number_of_states,number_of_states);
number_of_out=number_of_states*fanout;% 跳頻頻點數(shù)Nt
for i=0:number_of_states-1
    for j=0:fanout-1
        [next_state,out_put]=G_func1(i,j,L,fanout);
        nextstate(i+1,j+1)=next_state;
        output(i+1,j+1)=out_put;
        input(i+1,next_state+1)=j;
    end
end 
% ********************************************************* %



depth_of_trellis=length(source);
% Es=1;
% Eb=Es/BPH;
Eb=1;
Es=BPH*Eb;
% Ej0=(Eb*number_of_out*Q)/(Eb_to_Nj);% 每個多音干擾的能量Ej0
Ej0=(Es*number_of_out)/(BPH*Q*Eb_to_Nj); % 每跳時間內每個多音干擾的能量Ej0
% sgma=sqrt(Eb/(2*Eb_to_No));% AWGN的均方根
sgma=sqrt(Eb/(2*Eb_to_No));% AWGN的均方根
% 原來這里是thyta=2*pi*rand;% 干擾音與跳頻信號的相對相位
demod_input=zeros(number_of_out,depth_of_trellis);
f=zeros(1,depth_of_trellis);
% rc=zeros(1,number_of_out);
% rs=zeros(1,number_of_out);
D=0; % D 記錄網(wǎng)格圖的當前狀態(tài),這里初始狀態(tài)是0狀態(tài)

% *******************信道和非相干解調部分:加多音干擾和噪聲,然后非相干解調****************** %
for i=1:depth_of_trellis % i表示網(wǎng)格圖的時間走勢
    rc=zeros(1,number_of_out);
    rs=zeros(1,number_of_out);
%     theta_s=2*pi*rand;
%     theta_j=2*pi*rand;% 干擾音與跳頻信號的相對相位,每一跳信號與干擾之間的相對相位都應該不同
    f(i)=output(D+1,source(i)+1); % f(i)是i時刻的分支轉移輸出,即i時刻的跳頻頻率號
    J=gen_multijammer(Q,number_of_out);% J 矩陣中存放Q個干擾音所在的頻率號,干擾音所在頻率號范圍也是[0,number_of_out-1]而不是[1,number_of_out]
    for j=0:number_of_out-1
        if (j==f(i))
            theta_s=2*pi*rand;% //random phase of the signal tone
            rc(j+1)=raylrnd(sqrt(Es/2))*cos(theta_s)+sgma*randn;
            rs(j+1)=raylrnd(sqrt(Es/2))*sin(theta_s)+sgma*randn;
        else
            rc(j+1)=sgma*randn;
            rs(j+1)=sgma*randn;
        end
    end
    jam_rayleigh=raylrnd(sqrt(Ej0/2));% 干擾音的幅度服從瑞利分布,瑞利分布的參數(shù)是sqrt(Ej0/2)
    for k=1:Q
        theta_j=2*pi*rand;% //random phase of each jamming tone
        for j=0:number_of_out-1
            if (j==J(k))
                rc(j+1)=rc(j+1)+jam_rayleigh*cos(theta_j);%改了,原來是rc(j+1)+sqrt(Ej0)*cos(thyta)
                rs(j+1)=rs(j+1)+jam_rayleigh*sin(theta_j);%改了,原來是rs(j+1)+sqrt(Ej0)*sin(thyta)
            end
        end
    end
    for j=0:number_of_out-1
        demod_input(j+1,i)=sqrt(rc(j+1)^2+rs(j+1)^2);
%         demod_input(j+1,i)=rc(j+1)^2+rs(j+1)^2;
    end
    D=nextstate(D+1,source(i)+1);
end
% **************** End of Channel and Noncoherent demodulation modular ***************** %

% ****************** Viterbi decoding modular ********************** %
state_metric=zeros(number_of_states,2);
survivor_state=zeros(number_of_states,depth_of_trellis+1);
for i=1:depth_of_trellis-L
    flag=zeros(1,number_of_states);
    if i<=L+1
        step=2^((L+1-i)*BPH);
    else
        step=1;
    end
    for j=0:step:number_of_states-1
        for m=0:fanout-1
            branch_metric=demod_input(output(j+1,m+1)+1,i);
            if((state_metric(nextstate(j+1,m+1)+1,2)<state_metric(j+1,1)...
                    +branch_metric)|flag(nextstate(j+1,m+1)+1)==0)
                state_metric(nextstate(j+1,m+1)+1,2)=state_metric(j+1,1)+branch_metric;
                survivor_state(nextstate(j+1,m+1)+1,i+1)=j;
                flag(nextstate(j+1,m+1)+1)=1;
            end
        end
    end
    state_metric=state_metric(:,2:-1:1);
end
for i=depth_of_trellis-L+1:depth_of_trellis
    flag=zeros(1,number_of_states);
    last_stop=number_of_states/(2^((i-depth_of_trellis+L-1)*BPH));
    for j=0:last_stop-1
        branch_metric=demod_input(output(j+1,m+1)+1,i);
        if((state_metric(nextstate(j+1,1)+1,2)<state_metric(j+1,1)...
            +branch_metric)|flag(nextstate(j+1,1)+1)==0)
            state_metric(nextstate(j+1,1)+1,2)=state_metric(j+1,1)+branch_metric;
            survivor_state(nextstate(j+1,1)+1,i+1)=j;
            flag(nextstate(j+1,1)+1)=1;
        end
    end
    state_metric=state_metric(:,2:-1:1);
end
state_sequence=zeros(1,depth_of_trellis+1);
for i=1:depth_of_trellis
    state_sequence(1,depth_of_trellis-i+1)=survivor_state((state_sequence(1,depth_of_trellis+2-i)...
        +1),depth_of_trellis-i+2);
end
decoder_output_symbol=zeros(1,depth_of_trellis-L);% length(decoder_output_symbol)=N,維特比譯碼后的輸出符號流
decoder_output=zeros(1,BPH*(depth_of_trellis-L));
for i=1:depth_of_trellis-L
    dec_output_deci=input(state_sequence(1,i)+1,state_sequence(1,i+1)+1);
    decoder_output_symbol(i)=dec_output_deci;
    if(BPH~=1)
        dec_output_bin=deci2change(dec_output_deci,BPH,2);
        decoder_output((i-1)*BPH+1:i*BPH)=dec_output_bin;
    else
        decoder_output(1,i)=dec_output_deci;
    end
end
% ******************** End of Viterbi Decoding Modular ****************** %

for i=1:N  %計算維特比譯碼之后的符號錯誤數(shù)
    if (decoder_output_symbol(i)~=source(i))
        vita_symbol_err(pp,rep)=vita_symbol_err(pp,rep)+1;
    end
end

for i=1:N*BPH % 計算維特比譯碼之后的比特錯誤數(shù)
    if(dsource(i)~=decoder_output(i))
       num_of_err(pp,rep)=num_of_err(pp,rep)+1;
   end
end

waitbar(rep/times,WTbar)
end % 與最外層"多少遍" for rep=1:times循環(huán)對應的end
close(WTbar)
waitbar(pp/length(Eb_to_Nj_in_dB),WTbarpp)
end % 與最最外層信干比循環(huán) pp=1:length(Eb_to_Nj_in_dB)對應的end
close(WTbarpp)




Pb=sum(num_of_err,2)/(N*times*BPH) % N 是一遍的符號流長度,總共進行times遍,共N*times個符號
symerr_num_biterr=zeros(2*length(Eb_to_Nj_in_dB),times);% symerr_num_biterr矩陣中奇數(shù)行是某一信干比下維特比譯碼后的2^BPH=4進制符號錯誤數(shù)
                                                        % 偶數(shù)行是對應的比特錯誤數(shù)
for i=1:length(Eb_to_Nj_in_dB)
    symerr_num_biterr(2*(i-1)+1,:)=vita_symbol_err(i,:);
    symerr_num_biterr(2*i,:)=num_of_err(i,:);
end