The attached 'power point' slide contains information (note most of the information may not be relevant but a few slides contain the relevant formulas) that should assist with solving the problem in the Word document (see attachments).
Suppose propagation delay is alpha, Short Interframe Space (SIFS) is alpha, Distributed Interframe Space (DEFS) is 3*alpha and RTS and CTS are 5*alpha respectively for CSMA/CA with RTS/CTS.
(a) What is the earliest time for the receiver to send the CTS message?
(b) If data packet is 100*alpha long, what is the shortest time for the receiver to send the ACK signal?
(c) Explain why SIFS is kept smaller than DIFS period?
(d) Can you make SIFS = 0?
The solution discusses prorogation delay in a wireless network.