Performance Anomaly: Customized Simulation Code

anomaly-sim.m

% Define conditions
cw_min    = 31;
msdu_size = 1500; % in bytes
slot_time = 20; % in microseconds
sifs_time = 10; % in microseconds
n         = 10;
mbps_f    = [11   11   11  ];
mbps_s    = [1    2    5.5 ];
mbps_icon = ['o', 'x', '+' ];

% Calculate (with long preamble)
slot = slot_time * 1e-6;
sifs = sifs_time * 1e-6;
difs = (sifs_time + 2 * slot_time) * 1e-6;
p_c = 1 - (1 - 1 / cw_min)^(n - 1);
t_cont = slot * ((1 + p_c) / (2 * n)) * (cw_min / 2);
s_d = (msdu_size + 34) * 8;
t_pr = 192 * 1e-6;
host11 = 0:1:n; % fast hosts
host01 = n:-1:0; % slow hosts
x_udp = zeros(length(mbps_f), length(host11));
for j = 1:length(mbps_f)
    bps_11 = mbps_f(j) * 1e+6; % fast bps
    bps_01 = mbps_s(j) * 1e+6; % slow bps
    t_ack_11 = 112 / bps_11;
    t_ack_01 = 112 / bps_01;
    for i = 1:length(host11)
        t_ov_11 = difs + t_pr + sifs + t_pr + t_ack_11;
        t_ov_01 = difs + t_pr + sifs + t_pr + t_ack_01;
        t_tr_11 = t_ov_11 + s_d / bps_11 + t_cont;
        t_tr_01 = t_ov_01 + s_d / bps_01 + t_cont;
        p_slow = ((host11(i) * host01(i) + (host01(i) * (host01(i) - 1)) / 2)) / ((n * (n - 1)) / 2);
        t_jam_udp = p_slow * t_tr_01 + (1 - p_slow) * t_tr_11;
        u_11 = t_tr_11 / (host11(i) * t_tr_11 + host01(i) * t_tr_01 + p_c * t_jam_udp * n);
        x_11 = u_11 * (s_d / (bps_11 * t_tr_11)) * bps_11;
        x_udp(j, i) = x_11 / 1e+6; % Mbps
    end
end

% Draw graph
figure;
hold on;
names = string(mbps_s) + " Mbps slow host";
for j = 1:length(mbps_f)
    plot(host01, x_udp(j, :), 'Marker', mbps_icon(j));
end
ylabel('Throughput (Mbps)');
xlabel('The number of slow hosts');
legend(names);

result.svg