Biomedical Engineering Reference
In-Depth Information
Wireless links from
sensor nodes to
router
Wireless links from
router to
coordinator
Router 2
Router 2
Router 1
Router 1
Patient 2
Patient 1
Coordinator
Coordinator
Router 3
Router 3
Router 4
Sensor
nodes
Patient 3
Patient 4
Fig. 3.4
Topology of WBAN for a multi-human monitoring environment
n
þ
N l
ðÞ
;
r
2
d
d
0
P
dB
ðÞ¼
P
0
;
dB
þ
a
ðÞ
ð
3
:
1
Þ
where d is the depth from the skin in millimeters, d
0
is the reference distance
(5 mm), P
0
;
dB
is the path loss at reference distance in dB, a is the fitting constant,
n is the path loss exponent and N l
ðÞ
;
r
2
ðð Þ
is a normally distributed random
variable with a mean of l and a standard deviation of r. Parameters in Table
3.1
are used during the simulations [
11
].
An indoor propagation channel model for UWB communication based on the
modified Saleh-Valenzuela model is developed for propagation channels 2 and 3 in
Fig.
3.5
. It consists of a discreet impulse response given by (
3.2
)[
12
]. Considering
an average communication distance of 2 m, statistical channel measurements for
CM1 channel model [
13
] is taken as the reference.
h
i
ðÞ¼
X
i
X
K
p
¼
0
X
L
q
¼
0
a
i
p
;
q
d t
T
p
s
i
p
;
q
ð
3
:
2
Þ
