. Calculate the overhead associated with the following transmission schemes:
a. Asynchronous transmission; 8 data bits, 1 start bit, 1 stop bit
b. Asynchronous transmission; 7 data bits, 1 start bit, 1 stop bit
c. Asynchronous transmission; 7 data bits, 2 start bits, 1 stop bit, 4 bit FCS
d. Synchronous transmission; 1000 bit data field, 8 bit preamble and 8 bit post amble
e. Synchronous transmission; 2000 bit data field, 8 bit preamble and 24 bit post amble.
8. Show a time sequence diagram for the following scenarios:
a. Stop-and-wait ARQ, frames 0,1, and 2 are transmitted successfully and frame 3 is in error and a successful resend of frame 3 occurs.
b. Go-back-N ARQ, frames 0,1,2 and 3 are sent. Frames 0,1, and 3 are received error free. Frame 2 is in error. Show the subsequent error correction.
Let us assume that 1000 bytes are required to be send at a transmission channel having speed of 100 bps.then the over head in the terms of time and bits can be calculated in the following manner.
a)Asynchronous transmission; 8 data bits, 1 start bit, 1 stop bit
(i) each bit we have overhead of 2bits.
(ii)now total overhead in bits= 1000 * 2=2000 bits
overhead in time=2000/100= 20 ...
The solution examines transmission schemes and time sequence diagrams. The stop-and-wait ARQ frames are provided.