Suppose an 802.11 DSSS station is configured to always reserve the channel with

Question

Suppose an 802.11 DSSS station is configured to always reserve the channel with the RTS/CTS sequence. This station suddenly wants to transmit some data. Suppose that as a result 1,000 bytes of data is sent to the MAC layer to be transmitted, and all other stations are idle at this time. As a function of SIFS and DIFS, and ignoring propagation delay and assuming no bit errors and no encryption overhead, calculate the time required to transmit the frame and receive the acknowledgment. Assume a transmission rate of 1 Mbps.

Explanation / Answer

A 802.11 frame without data is 32 bytes each.

Assuming a transmission rate of 11 Mbps, the time to transmit a control frame (such as RTS frame, a CTS frame, or an ACK frame) is (256 bits)/(11 Mbps) = 23 µsec.  

The data is 1000bytes, so the time required to transmit the data frame is

(1000*8+256 bits)/(11 Mbps)=(8256 bits)/(11 Mbps)=751 µsec.

So the transmission time is

DIFS + RTS + SIFS + CTS + SIFS + FRAME + SIFS + ACK = DIFS + 3 SIFS + (3 *23 + 751) µsec = DIFS + 3 SIFS + 820 µsec.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.