Q1: In an IEEE 802.11b WLAN BSS, where only the Distributed Coordination Function is operational, station STA1 needs to send two data frames to station STA2 via the access point AP using the 2-way frame exchange. Assume that each station always chooses the same random number for the contention window as follows: STA1 always chooses 2, AP always chooses 1, and STA2 always chooses 0. Also, assume that SIFS=10s, DIFS=50s, Slot Time = 20s, ACK=14 bytes, RTS=20 bytes, CTS=14 bytes, Data Frame Header =34 bytes, the transmission rate R = 11 Mbps, and the payload of each data frame is 2312 bytes. a) Draw an approximate timing diagram showing all the transmitted frames until the two data frames are delivered to STA2. b) What is the percent overhead associated with transmitting the two data frames? c) What is the effective throughput achieved by sending the two data frames? Elaborate on the result. Q2: Repeat Q1 assuming 4-way frame exchange. Determine the percent change in performance compared to Part 1. Q3: Repeat Q1 assuming 4-way frame exchange and that each frame is fragmented into two equal-size fragments. Determine the percent change in performance compared to Part 1. Q4: Repeat Parts (b) and (c) for each of the three questions above and compare with the results in Q1, assuming that: 1. STA1 has 100 frames to send to STA2 2. The payload of each frame is 250 bytes. 3. CW=15. 4. No collisions occur. That is, STA1 and AP always choose different random numbers. Hint: calculate the average performance metrics. Q5: Repeat Q4 assuming that STA1 sends the frames to a wired station connected via a 1 Gbps DS. Q6: In an IEEE 802.11b WLAN BSS, where only the Distributed Coordination Function is operational, station STA1 needs to send two data frames to station STA2 via the access point AP using the 2-way frame exchange. Assume that each station always chooses the same random number for the contention window as follows: STA1 always chooses 2, AP always chooses 1, and STA2 always chooses 0. Also, assume that SIFS=10s, PIFS=30s, DIFS=50s, Slot Time = 20s, ACK=14 bytes, RTS=20 bytes, CTS=14 bytes, Data Frame Header =34 bytes, the transmission rate for STA1 is R1 = 2 Mbps and for STA2 is R2 = 11 Mbps, and the payload of each data frame is 2312 bytes. Suppose that the two frames are ready at STA1 at time t=100ms and that STA2 is in power-save polling mode. The next Beacon Frame (BF) is scheduled to be broadcast at t=107ms. The BF size is 40 bytes and it is usually transmitted at the lowest allowable data rate. Assume that AP uses PIFS to send the BF. a) Draw an approximate timing diagram showing all the transmitted frames until the two data frames are delivered to STA2. b) Determine the total transmission times it takes the MAC sublayer to deliver the two frames to STA2. Q7: Repeat Q6 assuming that BF is scheduled to be broadcast at t=150ms