Question 4 (15 marks) Sink A wireless sensor network is composed of three nodes and a Sink (see reference network topology above). The three nodes are equipped with temperature sensors and are set to sample 1 temperature measurement everysecond The temperatureeadingis carriedby packetsthatare L =128 [bytes] long. Assuming that: [1] The energy required to operate the radio module for each bit (both for receiving and transmitting) is E, = 50 [n]/bit]; [2] The energy required to successfully transmit a message over distance d is E (d) =kd2 [n]bit], where k =1; [3] d = =[metre$ Then, calculate the energy consumed by each individual node if: a) The nodes transmit their temperature reading directly to the Sink b) The nodes are organised in a cluster with node 3 as cluster-head. Let the network lifetime be defined as the time interval between the start of the network operation and the moment when the first node runs out of energy. In the previous network, if all the nodes initially have E =100 [m] available energy each, calculate the network lifetime in both scenarios