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Internet of Things, Exam 20-2-2017 Available time: 1 hour, 30 minutes 1 – Exercise (6 points) A personal area network (PAN) is operated according to the IEEE 802.15.4 beacon enabled mode. The Collision Access Part (CAP) is composed of 20 slots, the inactive part is composed of 2000 slots and the duty cycle is 2%; each slot (of CAP and CFP) carries 127 [byte] packets and the nominal data rate is 250 [kb/s]. Find (i) the total number of available slots in the CFP, (ii) the equivalent rate of the channel defined as “one slot per beacon interval”. Using the numbers found in (i) and (ii), suppose now that two motes are active in the PAN with a required uplink rate, r, defined as follows P(r=1200 [bit/s])= 0.3, P(r=600 [bit/s])= 0.3, P(r=200 [bit/s])= 0.4. (iii) Define a consistent slot assignment in the CFP for the two motes (the motes do not use the CAP). (iv) how many additional motes requiring a channel of 120 [bit/s] could be added to the network? 2 – Exercise (5 points) A personal area network (PAN) is composed of 10 motes and a PAN coordinator. The Beacon Interval duration is BI= 12[s]. Each mote is assigned a slot in the GTS within the Beacon Interval. Five motes are characterized by a traffic which is distributed as Poisson point process with parameter λ1= 0.1 [packet/s] whereas the remaining five motes are characterized by a traffic distributed according to Poisson with parameter λ2= 0.5 [packet/s]. The overall TX/RX energy (circuitry + transmission/reception) per slot is Etx=50 [uJ]. The energy for being idle in a slot is Eidle=20 [uJ]. The sleeping energy is negligible. Write the expression of the average energy consumed by the PAN coordinator within one Beacon Interval 3 – Exercise (6 points) A RFID system is composed of 2 tags. Find the collision resolution…