Question $2(25$ marks$)$

Automatic repeat request $($ARQ$)$ technique are used to control transmission error caused by channel noise. Stopand$-$Wait $($SW$)$ ARQ as shown in Figure Q$4$ is a simple protocol for handling frame transmission errors.

i$.$ Elaborate the operation of SW ARQ based on Figure Q$4.$

ii$.$ Assume that the frame size is $100$ bits and the BER is $10-5.$ Calculate the average number of retransmission for a window.

iii. What is the efficiency of the system $($in percentage$).$ Relate you findings to the average number of frame retransmission in $($iii$).$

iv$.$ What will happen to the average number of transmission and the efficiency if the BER is increase?

v$.$ Go$-$Back$-$N and Selective repeat are other ARQ protocols. Compare these two protocols and conclude on a protocol that is best for real time traffic application