1. Wireless Sensor Networks M Homework #1

2. Part 1 Consider two sensor devices (one transmitter and one receiver) IEEE 802.15.4 standard- compliant. Assume that the Loss in dB between the two nodes at distance d, is given by: L[dB]=k 0 +k 1 ln(d) Where k 0 =40 dB, k 1 =17.37 and ln is the natural logarithm. By setting the bilateral power spectral density of the receiver, N 0 = 8*10 -20 W/Hz and the transmit power, P t = 0 dBm, which is the maximum distance between the two devices, such that the Block Error Rate, BLER is lower than 10 -2, when a data block composed of 10 Bytes is transmitted?

3. Part 2 Two IEEE 802.15.4 sensor nodes (one transmitter and one receiver) are d meters apart at a height of 1 m above the ground. When the transmitter takes a sample from the environment, it encodes it with 4 bytes and transmits it through a data block composed of 30 bytes overall. The link uses channel 24 of IEEE 802.15.4, with transmission power set at 0.1 mW. In the presence of obstacles (like ground) a propagation coefficient, , equal to 2.5 should be considered. The bilateral power spectral density of the receiver, N 0 = 9*10 -18 W/Hz The energy consumed by the transmitting node to send the data is 60  J. The initial battery charge is 20 000 J. The energy consumed by the receiving node to receive the data is 50  J. Its initial battery charge is 10 000 J. 1)By setting the transmitter and receiver distance, d, to the maximum value satisfying the free space conditions, compute the BLER 2)Now set d=40 m and compute the BLER 3)Assuming the application requires to receive one sample every 16 ms, compute the link lifetime