Question: A wireless sensor network is composed of 100 memory-constrained sensor nodes whose buffer at the MAC layer can host at most one data packet. Hence, at any given node, a new packet is discarded whenever it finds the buffer occupied upon its arrival. These nodes sense a physical phenomenon and generate packets according to a Poisson process with rate λ = 0.2 packet/s. Moreover, they communicate with a common data-collection node through a shared wireless channel using a polling access scheme with switchover time The remaining channel parameters are: packet size L = 80 bytes and constant transmission rate Rb = 255 kbit/s.
a) Compute the mean polling cycle time for this system.
b) Compute the throughput of the system expressed in packet/s.
c) Compute the probability that a packet is discarded at any given node upon finding the buffer occupied.