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Internet of Things Prof. M. Cesana Exam– September 20, 2012 Family Name Given Name Student ID Total Available time: 2 hours Important: use the blank space after each exercise for your answers. E1 E2 E3 Questions Questions OS 1 – Exercise (7 points) A personal area network (PAN) is composed of 100 motes and a PAN Coordinator. The PAN works in beacon-enabled mode. • 50 motes of Type 1 are equipped with light sensors that require a deterministic communication channel to the PAN Coordinator of 100 [bit/s] • 20 motes of Type 2 are equipped with accelerometers and require to report deterministically to the PAN coordinator an acceleration sample at 500 [bit/s] • 30 motes of Type 3 which have statistical (non-deterministic) traffic towards the PAN coordinator characterized by the following probability distribution: P(required rate=0)= 0.8 P(required rate=100 [bit/s])= 0.1 P(required rate=1 [kbit/s])= 0.1 Assuming that: • the active part of the Beacon Interval (BI) is composed of Collision Free Part only; • the motes use 127 [byte] packets to communicate with the PANC which fit exactly one slot in the CFP • the duty cycle is 5% Find 1. The transmission rate 2. The duration of the single slot, the duration Beacon Interval (BI), the duration of the CFP and the duration of the inactive part. 3. The average energy consumption in a BI for a mote of Type 3 if the energy for receiving/transmitting in a slot is Etx=3 [mJ], the energy of being idle in a slot is Eidle = 1.5 [mJ] and the energy for sleeping is Esleep = 1.5 [uJ]. 2 – Exercise (6 points) A linear personal area network (PAN) is composed of 3 close-by motes and a distant Gateway. The communication is performed by electing a cluster head among the three motes which collects the traffic from the other motes and send it remotely…