Precursors of CSMA/CD
ALOHA (Pure ALOHA, Slotted ALOHA)
F: frame transmission time (assume constant)
S: throughput (average # of successful frame transmissions per F)
G: offer load (average total # of transmission attempts (including retransmission) per F)
Pure ALOHA Throughput
Slotted ALOHA Throughput
MATLAB Simulation of throughputs of Pure and Slotted ALOHA
g = 0 : 0.0001 : 2;
S1 = g .* exp(-2 * g); % Pure ALOHA
S2 = g .* exp(-g); % Slotted ALOHA
figure;
plot(g, S1);
hold on
plot(g, S2);
title("Throughput of Pure and Slotted ALOHA");
xlabel("average total transmissions");
ylabel("throughput");
grid on
Program output:
