dhrma.m

本源码是用于ad hoc中一种改进的预约多址协议的仿真

slot=10;              %时隙数
length=slot+1;
minislot=10;           %其它微时隙数
prop0=0.8;              %有业务节点竞争微时隙0的概率
prop1=0.5;              %有业务节点竞争其它微时隙的概率
t1=1;                   %一个突发平均持续时间，1s
lengofr=0.0444;         %一个帧长，单位秒
lengopa=4;             %一个业务分组长，单位kbit
profin=1-exp(-lengofr/t1);  %一个话音业务在一帧内结束的概率
node=15;
loopnum=20;

a=zeros(length,length);             %各矩阵初始化
b=zeros(length,1);
p=zeros(length,1);
lan=zeros(1,loopnum);
x=zeros(1,length);
z=zeros(1,length);
throughput=zeros(1,loopnum);
drop=zeros(1,loopnum);



for i=1:loopnum
    landa=0.05*i;
    lan(i)=landa;
    notraf=exp(-landa);
    traf=1-notraf;           %节点有业务的概率
    suc0=prop0;
    suc1=0;
    for k=1:minislot
        suc1=suc1+(1-prop0)*((1-prop1)^(k-1))*prop1;
    end
    succ=suc0+suc1;               %有业务节点竞争某个空闲时隙成功概率
 
    for n=1:length                    %对状态转移矩阵a第一行赋值
        sum1=0;
        for k=0:node
            sum1=sum1+groups(node,k)*(notraf^(node-k))*((traf*(1-succ))^k);
        end
        a(1,n)=leav(n-1,n-1,profin)*sum1;
    end
    
    for m=2:(length-1)                      %n表示当前状态，m表示下一个状态，给矩阵a赋值
        for n=1:length
            if m>n
                for c=0:(n-1)
                    sum1=0;
                    for r=(m-n+c):node
                        sum2=0;    
                        for k=0:(m-n+c-1)
                            sum2=sum2+(r-k)*succ*((1-succ)^(r-k-1));
                        end
                        sum1=sum1+(notraf^(node-r))*(traf^r)*groups(r,m-n+c)*sum2;
                    end
                    a(m,n)=a(m,n)+leav(n-1,c,profin)*sum1;
                end    
            else
                sum3=0;
                for k=0:node
                    sum3=groups(node,k)*(notraf^(node-k))*((traf*(1-succ))^k);
                end
                first=leav(n-1,n-m,profin)*sum3;
                second=0;
                for c=(n-m+1):(n-1)
                    sum1=0;
                    for r=(n-m+c):node
                        sum4=0;
                        for k=0:(m-n+r-1)
                            sum4=sum4+(r-k)*succ*((1-succ)^(r-k-1));
                        end
                        sum1=sum1+(notraf^(node-r))*(traf^r)*groups(r,m-n+c)*sum4;
                    end
                    second=second+leav(n-1,c,profin)*sum1;
                end
                a(m,n)=first+second;
            end
        end
    end
   for m=1:(length-1)
        for n=1:(length-1)
            if m==n
                a(m,n)=a(m,n)-1;
            end
        end
    end
    
    for n=1:length
        a(length,n)=1;
        b(n,1)=0;
    end
    b(length,1)=1;
    a
    
    p=a\b;               %求系统每个状态的概率
    
    %求解吞吐量
    for h=0:(length-2)
        sum5=0;
        for k=1:(slot-h)
            sum6=0;
            for r=k:node
                sum1=0;
                for u=0:(k-1)
                    sum1=sum1+(r-u)*suc0*((1-succ)^(r-u-1));
                end
                sum6=sum6+(notraf^(node-r))*(traf^r)*groups(r,k);
            end
            sum5=sum5+k*sum6;
        end
        x(h+1)=h+sum5;
    end
    x(length)=slot;
    throughput(i)=x*p*lengopa/lengofr;
    
    %求丢包率
    for h=0:(length-2)
        for k=1:(slot-h)
            sum8=0;
            for r=k:node
                sum1=0;
                for u=0:(k-1)
                    sum1=sum1+(r-u)*suc0*((1-succ)^(node-r-1));
                end
                sum8=sum8+(notraf^(node-r))*(traf^r)*(r-k*groups(r,k)*sum1)/(r*(notraf^(node-r))*(traf^r)+h);
            end
            z(h+1)==z(h+1)+sum8;
        end
    end
    for r=1:node
        z(length)=z(length)+r*(notraf^(node-r))*(traf^r)/((notraf^(node-r))*(traf^r)+slot);
    end
    drop(i)=z*p;
end
    
    subplot(1,2,1);
    plot(lan,throughput);
    
    subplot(1,2,2);
    plot(lan,drop);