csma/ca和csma/cd的matlab仿真源代码带有详细的注释

function [AllFrame SuccessFrame] = Csmaca(NumberNodes,ConWindow) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 步骤一 : 初始化 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% TRUE = 1; %表示事件为真 FALSE = 0; %表示事件为假 ACK = 2.8; %ACK帧相当于0.5个时隙 SIFS = 10.5; %SIFS帧相当于0.5个时隙 DIFS = 12.5; %DIFS帧相当于2.5个时隙 AllNumber = 0; %发送的总个数 SuccessNumber = 0; %发送成功的个数 SendEndTime = 0; %发送结束时间 SendEndTimeTemp = zeros(1,NumberNodes); %发送结束时间矩阵 ConWinStart = 0; %竞争起始时间 SendStart = zeros(1,NumberNodes); %记录进入碰撞期时间 ConWinEnd = ConWinStart+ConWindow; %竞争结束时间 SlotTime = 20*10^(-3); %时隙 AllSlotTime = 15*NumberNodes/SlotTime; %总时隙个数 BufferSize = 1500; %帧缓冲区大小 ChannelBusyFlag = 0; %信道忙闲标志 CollisionHandleFlag = 0; %冲突碰撞处理发送标志 ArrivalTime = zeros(1,NumberNodes); %帧到达时间 FrameLength = zeros(1,NumberNodes) ; %帧长 HasFrameFlag = zeros(1,NumberNodes); %帧缓存有无帧标志 CountBackoff = zeros(1,NumberNodes); %退避次数 BackoffTime = zeros(1,NumberNodes); %退避时间 FrameBuffer = zeros(NumberNodes,1501); %帧缓冲器 CollisionNodes = zeros(1,NumberNodes+1); %冲突节点记录 CurBufferSize = zeros(1,NumberNodes); %当前帧缓冲区已用大小 sign = 1; for i = 1:NumberNodes ArrivalTime(i) = ceil(20*rand()); %初始化帧到达时间 FrameLength(i)=10; %初始化帧长度 CountBackoff(i) = 0; %初始化退避次数 BackoffTime(i) =0; %初始化退避时间 end RecordBackoffTime=zeros(NumberNodes,AllSlotTime); %记录站点的退避时间 RecordSendTime=zeros(NumberNodes,400,3); %记录数据发送成功过程 SendNodeIndex=zeros(1,NumberNodes); %记录数据发送成功过程下标 RecordSendTimeFail=zeros(NumberNodes,400,3); %记录数据发送失败过程 SendNodeIndexFail=zeros(1,NumberNodes); %记录数据发送失败过程下标 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %步骤2：CSMA/CA循环处理开始 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% for t = 1:AllSlotTime %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %步骤2.1：帧进缓冲区，根据不同情况进行处理 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% for i = 1:NumberNodes if t == ArrivalTime(i) %有新的帧需要发送，则先放入缓冲区 if CurBufferSize(i) < BufferSize - FrameLength(i) %如果帧缓冲区还可以未满 %fprintf('第%d个节点%d时刻%d长的帧进入缓冲区！\n',i, ArrivalTime(i),FrameLength(i)); FrameBuffer = FramePush(FrameBuffer,i,FrameLength(i)); %则将帧放入缓冲区，否则丢弃次帧 CurBufferSize(i) = CurBufferSize(i) + FrameLength(i); %修改当前缓冲区已存帧的总长度 if HasFrameFlag(i) == FALSE %当缓冲区没有帧，此时有帧进入 HasFrameFlag(i) = TRUE; %把有帧标志设为1 if ChannelBusyFlag== FALSE %当信道空闲 BackoffTime(i)=0; %退避时间置为0 else BackoffTime(i)=SetBackoffTime(1); %否则退避时间置为一随机时间 end end end sign=sign+1; %不断生成新的帧 if sign<NumberNodes*30 ArrivalTime(i) = ceil(4*rand()) + 10 + t; FrameLength(i) = ceil(5+5*rand()); end end %fprintf('第%d时刻第%d个节点的退避时间为%d！\n',t,i, BackoffTime(i)); %打印出退避时间 if RecordBackoffTime(i,t)==0 RecordBackoffTime(i,t)=BackoffTime(i); %记录退避时间 end end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %步骤2-2：统计此刻准备发送数据的节点 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% for i = 1:NumberNodes if ChannelBusyFlag == FALSE %信道闲 if HasFrameFlag(i) == TRUE %有帧待发送且信道空闲 if BackoffTime(i) == 0 %如果退避时间为0， if SendStart(i)==0 %SendStart（i）避免重复加入碰撞节点 CollisionNodes = AddNode(CollisionNodes,i); %记录退避时间为0的节点 SendStart(i) = t; %记录发送时间 if CollisionNodes(1)==1 ConWinStart = t; %竞争期开始时间 ConWinEnd = t + ConWindow; %竞争期结束时间 CollisionHandleFlag= TRUE; %冲突处理标志为真 %fprintf('%d时刻争用期开始！\n',t); end %fprintf('%d时刻节点%d进入争用期！\n',t,i); end else BackoffTime(i)= BackoffTime(i)-1; %退避时间不为0，则退避时间减1 end end end end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %步骤2-3：分情况处理统计的节点 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if CollisionHandleFlag == TRUE&&t==ConWinEnd %有节点退避时间为0 %fprintf('%d时刻争用期结束！\n',t); n = CollisionNodes(1); %参与碰撞节点个数 AllNumber = AllNumber+n;