CSMA_CA.rar_CSMA/CA_Different_random access

function [status, timer,comm,counter,flag,ack] = state_machine(pre_status_matrix, pre_next_status_timer,pre_comm_matrix,frame_size... ,back_off_counter,first_frame_flag,priority_matrix,max_DIFS,x_position,y_position,ack_matrix) global plot_flag; %Stacte table % 0: idle(nothing to send) % 1: waiting for the media available (have something to send) % 2: Free media and wait for DIFS (have something to send) % 3: Sending Data % 4: waiting for SIFS % 5: sending ACK % 6: wait for ACK % -1: Random back-off (Data collision) back_off_base=4; max_back_off=8; len=size(pre_status_matrix,1); status=zeros(len,1); timer=zeros(len,1); comm = zeros(len,1); counter=back_off_counter; flag=first_frame_flag; ack=ack_matrix; for i=1:len % go through each nodes; count=0; % count the number of node sending data at the same time if >1 there is a collision busy_flag=0; switch pre_status_matrix(i,1) case 0 %pre state is idle for j=1:len %check if we receive message if(pre_status_matrix(j,2)==3&&first_frame_flag(j)==1) frame_size(i)=frame_size(j); count=count+1; tmp=pre_comm_matrix(j); end end if (count==1&&tmp==i) % need to receive message status(i)=7; % go to ceceive state timer(i)=frame_size(i); comm(i)=pre_comm_matrix(i); elseif(pre_comm_matrix(i)==0) % don need ack message check comm matrix nothing to send stay idle status(i)=0; timer(i)=0; comm(i)=pre_comm_matrix(i); else %have something to send check if channel is busy comm(i)=pre_comm_matrix(i); for j=1:len if(i~=j && pre_status_matrix(j,2)==3||pre_status_matrix(j,2)==5) %channel is busy status(i)=1; timer(i)=0; busy_flag=1; end end if(busy_flag==0) % channel is not busy status(i)=2; timer(i)=randi([max_DIFS-priority_matrix(i) max_DIFS]); end end case 1 %pre state is waiting for media vailiable comm(i)=pre_comm_matrix(i); for j=1:len %check if we receive message if(pre_status_matrix(j,2)==3&&first_frame_flag(j)==1) frame_size(i)=frame_size(j); count=count+1; tmp=pre_comm_matrix(j); end end if (count==1&&tmp==i) % need to receive message status(i)=7; % go to ceceive state timer(i)=frame_size(i); comm(i)=pre_comm_matrix(i); else %then keep sensing the channel for j=1:len if(pre_status_matrix(j,2)==3||pre_status_matrix(j,2)==5) %channel is busy status(i)=1; timer(i)=0; end end if(status(i)~=1) % channel is not busy status(i)=2; timer(i)=randi([max_DIFS-priority_matrix(i) max_DIFS]); end end case 2 %pre state is waiting DFS comm(i)=pre_comm_matrix(i); if(pre_status_matrix(i,2)==3) % already start sending data status(i)=3; timer(i)=frame_size(i); % sx=x_position(i); % sy=y_position(i); % dx=x_position(comm(i)); % dy=y_position(comm(i)); % plot_line(sx,sy,dx,dy,'y') plot_flag(i,1)=1; plot_flag(i,2)=1; plot_flag(i,3)=x_position(i); plot_flag(i,4)=y_position(i); plot_flag(i,5)=x_position(comm(i)); plot_flag(i,6)=y_position(comm(i)); else for j=1:len if(i~=j && pre_status_matrix(j,2)==3 || pre_status_matrix(j,2)==5) %channel is busy status(i)=1; timer(i)=0; end end if(status(i)~=1) % channel is not busy status(i)=2; timer(i)=pre_next_status_timer(i)-1; end if(status(i)==2 && timer(i)==0) %finish DIFS start sending Data status(i)=3; timer(i)=frame_size(i); flag(i)=1; plot_flag(i,1)=1; plot_flag(i,2)=1; plot_flag(i,3)=x_position(i); plot_flag(i,4)=y_position(i); plot_flag(i,5)=x_position(comm(i)); plot_flag(i,6)=y_position(comm(i)); end for k=1:len %check if we receive message if(pre_status_matrix(k,2)==3&&first_frame_flag(k)==1) frame_size(i)=frame_size(k); count=count+1; tmp=pre_comm_matrix(k); end end if (count==1&&tmp==i) % need to receive message status(i)=7; % go to ceceive state timer(i)=frame_size(i); comm(i)=pre_comm_matrix(i); end end case 3 %pre state is sending data comm(i)=pre_comm_matrix(i); %keep sending and timer -1 status(i)=3; timer(i)=pre_next_status_timer(i)-1; flag(i)=0; if(timer(i)==0) %finished sending data, begin waite for ACK status(i)=6; timer(i)=4; end case 4 %pre state is waiting for SIFS comm(i)=pre_comm_matrix(i); status(i)=4; timer(i)=pre_next_status_timer(i)-1; if(timer(i)==0) %finished waiting SIFS status(i)= 5; timer(i)=2; % sx=x_position(i); % sy=y_position(i); % dx=x_position(ack(i)); % dy=y_position(ack(i)); %