dhrma_sim.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=0.4;              %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=2;

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
    con0=traf*prop0;
    con1=traf*prop1;
    suc0=con0;
    suc1=0;
    for k=1:minislot
        suc1=suc1+(1-con0)*((1-con1)^(k-1))*con1;
    end
    succ=suc0+suc1;               %任意一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
       a(1,n)=leav(n-1,n-1,profin)*slot*((1-succ)^node);
    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 k=0:(m-n+c-1)
                        sum1=sum1+(node-k)*succ*((1-succ)^(node-k-1));
                    end
                    a(m,n)=a(m,n)+leav(n-1,c,profin)*sum1;
                end    
            else
                first=leav(n-1,n-m,profin)*(slot-m)*((1-succ)^node);
                second=0;
                for c=(n-m+1):(n-1)
                    sum2=0;
                    for k=0:(m-n+c-1)
                        sum2=sum2+(node-k)*succ*((1-succ)^(node-k-1));
                    end
                    second=second+leav(n-1,c,profin)*sum2;
                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)
        sum3=0;
        for k=1:(slot-h)
            sum4=0;
            for r=0:(k-1)
                sum4=sum4+(node-r)*suc0*((1-succ)^(node-r-1));
            end
            sum3=sum3+k*sum4;
        end
        x(h+1)=h+sum3;
    end
    x(length)=slot;
    throughput(i)=x*p*lengopa/lengofr;
    
    %求丢包率
    tot_tra=node*traf;
    for h=0:(length-2)
        sum5=0;
        for k=1:(slot-h)
            sum6=0;
            for r=0:(k-1)
                sum6=sum6+(node-r)*suc0*((1-succ)^(node-r-1));
            end
            sum5=sum5+k*sum6;
        end
        z(h+1)=(tot_tra-sum5)/(tot_tra+h);
    end
    z(length)=tot_tra/(tot_tra+slot);
    drop(i)=z*p;
end
    
    subplot(1,2,1);
    plot(lan,throughput);
    
    subplot(1,2,2);
    plot(lan,drop);