Wireless Sensor Networks M

flangeeasyMobile - Wireless

Nov 21, 2013 (3 years and 10 months ago)

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Wireless
Sensor

Networks

M


Homework

#1


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
=

7*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?

Part 2

Two
IEEE 802.15.4 sensor
nodes are d meters apart at a height of 2 m above the
ground
.


The transmitting node takes a sample every 16
ms
, encodes it with four bytes and
transmits it through
a data
burst composed of 30 bytes overall.


The
link uses channel 25 of
IEEE 802.15.4
. with transmission power set at 0.1
mW
.


The
bilateral power spectral density of the receiver, N
0
=

8*10
-
18

W/Hz


The
energy consumed by the transmitting node to send the data is 50
m
J
. The initial
battery charge is
20
000 J. The energy consumed by the receiving node to receive
the data is 60
m
J
. Its initial battery
charge
is 10 000 J.


1
) Assuming d = 40 m, compute the
BLER

2) Compute the
link

lifetime