12 mA-hr), and in flash writing (0.02 mA-hr), we get a total
of approximately 18.14 mA-hr of energy consumed in 1 reprogramming.
Therefore, in ExScal, erepr = 18.14 mA-hr.
elocalization: Energy spent in one localization. As seen in the calculation
done above for reprogramming, the energy consumed in staying awake
is the dominant part of energy consumption. In ExScal, the XSMs were
awake for 10 minutes during localization, consuming 4 mA-hr. Therefore,
elocalization = 4mA-hr.
4.3 Lifetime in the Fully Active Mode
If a sensor node is always in the active mode, its lifetime, ?„“hr (in hours) will
be given by:
?„“hr =
ebattery ??’ frepr ?¤ erepr ??’ elocalization
iproc
act + irad
act + imsg
act + isensor
. (5)
Substituting the following values
imsg
act = 0.02mA, (from (2))
isensor = 0.292 + 0.575 + 6.48 = 7.347mA, (from Table 2)
and those from Table 4, we obtain ?„“hr = 72.2 hours (or three days) for the
lifetime of ExScal.
4.4 Lifetime When Using Low Power Listening (LPL)
If we use the low power listening mode (see Section 2.1), then the network
lifetime, ?„“hr (in hours) is given by
?„“hr =
ebattery ??’ frepr ?¤ erepr ??’ elocalization
ilpl + imsg
lpl + isensor + ievent
awk
. (6)
Substituting
significant energy. Also, it will take much longer than 45 minutes to reprogram the
network if the XSMs are in the LPL mode, because of reduced channel capacity
in the LPL mode.
276
ilpl =
(0.1974 ?¤ tlpl
slp) + (9.
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