LTP5901-IPR_15 Datasheet, PDF (14/32 Pages) Linear Technology – SmartMesh IP Network Manager 2.4GHz 802.15.4e Wireless Embedded Manager

LTP5901-IPR/LTP5902-IPR
Typical Performance Characteristics
In mesh networks data can propagate from the manager
to the nodes, downstream, or from the motes to the man-
ager, upstream, via a sequence of transmissions from one
device to the next. As shown in Figure 8, data originating
from mote P1 may propagate to the manager directly or
through P2. As mote P1 may directly communicate with
the manager, mote P1 is referred to as a 1-hop mote. Data
originating from mote D1, must propagate through at least
one other mote, P2 or P1, and as a result is referred to as
a 2-hop mote. The fewest number of hops from a mote to
the manager determines the hop depth.
Asdescribedin theApplicationTimeSynchronizationsection,
Eterna provides two mechanisms for applications to
maintain a time base across a network. The synchroniza-
tion performance plots that follow were generated using
the more precise TIMEn input. Publishing rate is the rate
a mote application sends upstream data. Synchroniza-
tion improves as the publishing rate increases. Baseline
synchronization performance is provided for a network
operating with a publishing rate of zero. Actual performance
for applications in network will improve as publishing
rates increase. All synchronization testing was performed
with the 1-hop mote inside a temperature chamber. Tim-
ing errors due to temperature changes and temperature
differences both between the manager and this mote and
between this mote and its descendents therefore propa-
gated down through the network. The synchronization
of the 3-hop and 5-hop motes to the manager was thus
affected by the temperature ramps even though they were
at room temperature. For 2°C/minute testing the tempera-
ture chamber was cycled between –40°C and 85°C at this
rate for 24 hours. For 8°C/minute testing, the temperature
chamber was rapidly cycled between 85°C and 45°C for
eight hours, followed by rapid cycling between –5°C and
45°C for eight hours, and lastly, rapid cycling between
–40°C and 15°C for eight hours.
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
5 10 15 20 25 30
PACKET RATE (PACKETS/s)
59012IPR F07a
Figure 7a. Supply Current vs Packet Rate
2.5
5 HOPS
4 HOPS
3 HOPS
2.0
2 HOPS
1 Hop
1.5
1.0
0.5
0
0
5 10 15 20 25 30
REPORTING INTERVAL (s)
59012IPR F07b
Figure 7b. Packet Latency vs Reporting Interval
MANAGER
P1
P2
1 HOP
P3
D1
2 HOP
14
3 HOP
D2
5800IPM F08
Figure 8. Example Network Graph
59012iprf
For more information www.linear.com/LTP5901-IPR or www.linear.com/LTP5902-IPR