matlab-基于matlab的CSMA-CA无线接入算法性能仿真,分析了不同工作站数量对VANET通信系统吞吐量的影响-源码

clc; clear; close all; warning off; addpath(genpath(pwd)); %**************************************************************************** %更多关于matlab和fpga的搜索“fpga和matlab”的CSDN博客: %matlab/FPGA项目开发合作 %https://blog.csdn.net/ccsss22?type=blog %**************************************************************************** maxCarNumber = 40; minCarNumber = 5; sResult = zeros(1,maxCarNumber - minCarNumber + 1); %记录结果用 for M = minCarNumber:maxCarNumber %M工作站数目 M ChannelBusy = 0; %信道忙闲标志 Start = 0; %有无数据开始发送标志 Collision = 0;%有无冲突标志 DeferenceTime = 0; %发送期 Throughput = 0;%吞吐量 ArrivalTime = zeros(1,M ); %到达时间 PacketLength = zeros(1,M) ; %帧长 HasPacket = zeros(1,M);%有无缓存标志 CW = zeros(1,M);%争用窗口 BackoffTimer = zeros(1,M);%回退时间 PacketBuff = zeros(M,1501); %缓存器 CollisionStations = zeros(1,M+1); %冲突站记录 PhyRate = 2*10^6 ; %物理层数据率 SlotTime = 20*10^(-6); %时隙间隔 TotalTime = 2/SlotTime; %观测总时隙个数 SIFS = 0.5; %SIFS相当于0.5个时隙 DIFS = 2.5; %DIFS相当于2.5个时隙 ACK = 14*8/(PhyRate*SlotTime); %ACK 转化成时隙个数 AverageArrivalTime = 110; %平均到达时间 AveragePacketLength = 50; %平均帧长 CurBufferSize = zeros(1,M); %当前缓存器帧长 Buffer_Threshold = 8*10^6/(PhyRate*SlotTime);%缓存门限 %activeArray = zeros(1,M); %carDistanceArray = cardistri(roadLength,M); %arInfmatrix(carDistanceArray); for i = 1:M ArrivalTime(i) = ProPoisson(AverageArrivalTime); %初始化到达时间 PacketLength(i) =ProPoisson(AveragePacketLength);%初始化分组长度 CW(i) = 32; %初始化竞争窗口 BackoffTimer(i) = 1000; %初始化退避时间 1000 end for t = 1:TotalTime for i = 1:M if t == ArrivalTime(i) %目前不能发送，push分组进PackeBuff，修改退避计数器 if CurBufferSize(i) < Buffer_Threshold - PacketLength(i) PacketBuff = Push(PacketBuff,i,PacketLength(i)); CurBufferSize(i) = CurBufferSize(i) + PacketLength(i); HasPacket(i) = 1; if BackoffTimer(i) == 1000 BackoffTimer(i) = ReSet(CW(i));%退避计数器达到最大1000时，重置退避计数器 end end %更新到达时间和帧长 ArrivalTime(i) = ProPoisson(AverageArrivalTime) + PacketLength(i) + t; PacketLength(i) = ProPoisson(AveragePacketLength); end end for i = 1:M if HasPacket(i) == 1 && ChannelBusy == 0 %PackeBuff中有数据包发送并且信道空闲 if BackoffTimer(i) == 0 %退避时间=0 -> 发送 CollisionStations = Add(CollisionStations,i);%加入冲突站点序列中 Start = 1; %activeArray(i) = 1; else BackoffTimer(i) = BackoffTimer(i) - 1;%退避时间!=0 -> 退避时间-1 end end end if Start == 1%信道改为忙碌 ChannelBusy = 1; n = CollisionStations(1); if n == 1%信道中只有一个站点发送数据则为正常发送情况 DeferenceTime = floor(t + SIFS + DIFS + ACK + PacketBuff(CollisionStations(2),2)); %PacketBuff(CollitionStations(2),2)数据长度 %成功发送时间 Collision=0;%没有碰撞 else DeferenceTime = floor(t + DIFS + MaxLength(PacketBuff,CollisionStations)); Collision=1;%发生碰撞 end Start=0; end if t == DeferenceTime && ChannelBusy == 1%信道忙的时候达到站点的等待时间 if Collision == 0 n = CollisionStations(2); CurBufferSize(n) = CurBufferSize(n) - PacketBuff(n,2); Throughput = Throughput + PacketBuff(n,2)* SlotTime * PhyRate; PacketBuff = Pop(PacketBuff,n); CW(n) = 32; k = PacketBuff(n,1); if k ==0%如果没有数据等待发送，将HasPacket置0，BackoffTimer置Max HasPacket(n) = 0; BackoffTimer(n) = 1000; else%还有数据分发送，修改碰撞计数器 BackoffTimer(n) = ReSet(CW(n)); end else n = CollisionStations(1); for i = 1:n j = CollisionStations(i+1); CW(j) = Increase(CW,j); BackoffTimer(j) = ReSet(CW(j)); end end CollisionStations = zeros(1,M+1); DeferenceTime = 0; ChannelBusy = 0; Collition = 0; end end sResult(M-4) = Throughput/(TotalTime* SlotTime * PhyRate);%吞吐率 end xline = minCarNumber:1:maxCarNumber; plot(xline,sResult,'b-o');%吞吐率与站点数目的关系 hold on; xlabel('工作站数目(个)'); ylabel('吞吐率'); title('工作站数目和吞吐率的关系'); grid;