LTP5901-IPM_15 Datasheet, PDF (3/32 Pages) Linear Technology – SmartMesh IP Node 2.4GHz 802.15.4e Wireless Mote Module

LTP5901-IPM/LTP5902-IPM
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 time slots, 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.
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 time slots
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.
A network begins to form when the network manager
instructs its on-board Access Point (AP) radio to begin
sending advertisements—packets that contain information
that enables a device to synchronize to the network and
request to join. This message exchange is part of the secu-
rity handshake 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.
HOST
APPLICATION
ALL NODES ARE ROUTERS.
THEY CAN TRANSMIT AND RECEIVE.
THIS NEW NODE CAN JOIN
ANYWHERE BECAUSE ALL
NODES CAN ROUTE.
SNO 02
NETWORK MANAGER
AP
Mote
1
Mote
2
Mote
3
SNO 01
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
to the network manager in packets called health reports.
At the heart of SmartMesh motes and network manag-
ers is the Eterna IEEE 802.15.4e System-on-Chip (SoC),
featuring Dust Networks’ highly integrated, low power
radio design, plus an ARM Cortex-M3 32-bit micropro-
cessor running SmartMesh networking software. The
SmartMesh networking software comes fully compiled
yet is configurable via a rich set of Application Program-
ming 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.
59012ipmf
For more information www.linear.com/LTP5901-IPM or www.linear.com/LTP5902-IPM
3