
LTP5901-IPR/LTP5902-IPR
3
59012iprf
For more information www.linear.com/LTP5901-IPR or www.linear.com/LTP5902-IPR
smarTmesh neTwork overview
A SmartMesh network consists of a self-forming multi-hop,
mesh of nodes, known as motes, which collect and relay
data, and a network manager that monitors and manages
network performance and security, and exchanges data
with a host application.
SmartMesh networks communicate using a time slotted
channel hopping(TSCH) link layer, pioneered by Dust
Networks. In a TSCH network, all motes in the network
are synchronized to within less than a millisecond. Time
in the network is organized into timeslots, which enables
collision-free packet exchange and per-transmission
channel-hopping. In a SmartMesh network, every device
has one or more parents (e.g. mote 3 has motes 1 and
2 as parents) that provide redundant paths to overcome
communications interruption due to interference, physical
obstruction or multi-path fading. If a packet transmission
fails on one path, the next retransmission may try on a
different path and different RF channel.
A network begins to form when the network manager
instructs its onboard access point (AP) radio to begin
sendingadvertisements—packets that contain information
that enables a device to synchronize to the network and
request to join. This message exchange is part of thesecu-
rityhandshake that establishes encrypted communications
between the manager or application, and mote. Once motes
have joined the network, they maintain synchronization
through time corrections when a packet is acknowledged.
to the network manager in packets called health reports.
The network manager uses health reports to continually
optimize the network to maintain >99.999% data reliability
even in the most challenging RF environments.
The use of TSCH allows SmartMesh devices to sleep in-
between scheduled communications and draw very little
power in this state. Motes are only active in timeslots
where they are scheduled to transmit or receive, typically
resulting in a duty cycle of < 1%. The optimization soft-
ware in the network manager coordinates this schedule
automatically. When combined with the Eterna low power
radio, every mote in a SmartMesh network—even busy
routing ones—can run on batteries for years. By default,
all motes in a network are capable of routing traffic from
other motes, which simplifies installation by avoiding the
complexity of having distinct routers vs non-routing end
nodes. Motes may be configured as non-routing to further
reduce that particular mote’s power consumption and to
support a wide variety of network topologies.
An ongoing discovery process ensures that the network
continually discovers new paths as the RF conditions
change. In addition, each mote in the network tracks per-
formance statistics (e.g. quality of used paths, and lists of
potential paths) and periodically sends that information
At the heart of SmartMesh motes and network managers
is the Eterna IEEE 802.15.4e System-on-Chip (SoC), fea-
turing Dust Networks’ highly integrated, low power radio
design, plus an ARM Cortex-M3 32-bit microprocessor
running SmartMesh networking software. The SmartMesh
networking software comes fully compiled yet is configu-
rable via a rich set of application programming interfaces
(APIs) which allows a host application to interact with
the network, e.g. to transfer information to a device, to
configure data publishing rates on one or more motes,
or to monitor network state or performance metrics. Data
publishing can be uniform or different for each device,
with motes being able to publish infrequently or faster
than once per second as needed.
HOST
APPLICATION
AP
NETWORK MANAGER
59012IPR SNO01
Mote
2
Mote
1
Mote
3
ALL NODES ARE ROUTERS.
THEY CAN TRANSMIT AND RECEIVE.
THIS NEW NODE CAN JOIN
ANYWHERE BECAUSE ALL
NODES CAN ROUTE.
59012IPR SNO02