packetloss.m

802.11仿真源码 对分析RSSI很有用的

function [Loss, Bursts] = PacketLoss(file_header)
% This function ->
%       PacketLoss: Given the packets file this program finds the
%       experiment 4 data and proceeds and collects the burst sizes of
%       packets. This is then graphed, that is, the packet error burst 
%       frequency is calculated and graphed. The loss rates is also
%       calculated and outputted to the screen. 

% Note: If the graph of the bursts of received packet is wanted, change the
% comparison on line 58 to a '0' 

filename = [file_header];

fid = fopen(filename,'r');

tline = fgets(fid);

z = 0;       %lost packet
o = 0;       %received packet
current = 1; %flag for a loss packet
count = 0;   %typical counter
room_back = 0;
mp_back = 0;
loop_cnt = 1;
line_counter = 0;

%  The Bur vector populates the index of the vector when a Bur of that
%  index has been found
Bur = zeros(50000,1); 

while(1)
   tline = fgets(fid);
   room = sscanf(tline,'%f');  % extract room number 
   mp = Extract(tline, 1);      % extract MP
   
   if((room == room_back) && (mp == mp_back))
       break;
   end
   
   room_back = room;
   mp_back = mp;
   line_counter = line_counter + 1;
end

%dont miss any lines
frewind(fid)
i = 1;
while(i <= line_counter)
    tline = fgets(fid);
    i = i + 1;
end

while(~feof(fid))
        
    tline = tline(9:length(tline));
    
    for (i=1:length(tline))
        if (tline(i)=='1') %1 = loss, 0 = received 
            o = o + 1; 
            if (current == 0) %Burst found
                Bur(count) = Bur(count) + 1; % increment relevent Bur size
                cnt(loop_cnt) = loop_cnt;    %index vector for plotting
                count = 0;
                current = 1;
            end
        else
            z = z + 1; 
            if (current == 0)
                count = count + 1;
            else
                current = 0;
                count = 1;
                loop_cnt = loop_cnt + 1;
            end
        end
    end
    tline = fgets(fid);
end

Total = z+o
Loss_is = ((z/Total)*100)
 
fclose(fid);

% Alters the x axis of the graph to a log scale for better viewing. 
for i=1:length(Bur)
    if Bur(i) == 0
        Bur(i) = 0;    
    else 
       Bur(i) = log(Bur(i));
     end
end

figure; bar(Bur, 0.8, 'r'); axis([1 90 0 9]); title('Packet Error Burst Frequency'); xlabel('Burst Size'); ylabel('Log(Freq)');