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Internet of Things February 12, 2016 Available time: 2h Exercise 1 (4 points) An RFID system is composed of 3 tags and uses a Dynamic Frame ALOHA access protocol. Assume that the first two frames are composed of r1=2 and r2=3 slots, respectively. What is the average number of tags correctly resolved after the first two frames? Exercise 2 (6 points) A personal area network (PAN) is operated according to the IEEE 802.15.4 beacon enabled mode. The Collision Access Part (CAP) of the superframe is composed of 20 slots. The inactive part of the beacon interval is composed of 1600 slots and the duty cycle is 4.04%. Each slot (of CAP and CFP) carries 127 [byte] packets. The nominal data rate is 250 [kb/s]. How many slots are available in the CFP? What is the rate of the channel defined as “one slot per beacon interval”? Using the numbers found above, suppose that two motes (Mote 1 and Mote 2) are active in the PAN with the following traffic patterns Ø P(amount of data generated in one BI=508[byte])= 0.3 Ø P(amount of data generated in one BI =127 [byte])= 0.3 Ø P(amount of data generated in one BI=635 [byte])= 0.4 Define a consistent slot assignment in the CFP for the two motes (the motes do not use the CAP). What is the total capacity of the CAP? Exercise 3 (6 points) The three nodes in the figure mount temperature sensors and are set to deliver 1 temperature sample to the sink at a frequency of 1 [Hz] for a total time of 50[s]. The temperature sample is carried by packets with size L=128[byte]. Assuming that: the energy for acquiring one temperature sample is Es=40[uJ], the energy required to operate the TX/RX circuitry is Ec=50 [nJ/bit], the energy required to support sufficient transmission output power Etx(d)= k d2 [nJ/bit], being k=1 [nJ/bit/m2], the energy for…