RC11xx(HP)-TM
RC25xx(HP)-TM
RC17xx(HP)-TM
2016 Radiocrafts AS
RC11xx(HP)/25xx(HP)/17xx(HP)-TM Data Sheet rev. 1.48 Page 7 of 86
2016 Tiny Mesh AS
Radiocrafts
Embedded Wireless Solutions
Gateway.
Router devices must always be powered, to support routing of packets received from other devices.
End Device
A Tinymesh™
END DEVICE
will normally be in low power sleep mode for battery operation. End Devices
have full input- and output control capabilities, but will not accept messages for re-distribution from other
devices.
An End Device will wake up to full power mode by external stimuli, such as a digital input level shift,
serial data input, pulse counter activity or by internal clock. Wakeup conditions are selectable through
configuration settings. After waking up, the End Device will generate an Event Message or a Serial in
Message, depending on the wake-up condition. After delivering the message, the End Device will either
return directly to sleep condition, or stay awake for a settable time period, to wait for response
commands from a server or application outside the Tinymesh™ network.
Data Integrity
The Tinymesh™ stack uses several mechanisms to ensure safe and reliable data delivery with minimal
latency.
•
Listen Before Talk in accordance with the harmonized EN 300 220-2 standard, to reduce
likelihood of RF traffic collision.
•
Link level acknowledge on all packet deliveries for positive confirmation of data reception.
•
Packet retransmission on missing acknowledge
•
Format, data validity and CRC control on check on packet reception
•
AES 128 encryption
•
Packet duplicate check
•
Housekeeping mechanisms to eliminate stray packets that are either too old or have hopped to
many times
•
Unique numbering of packets to allow duplicate and sequence control by external applications
•
Application level command acknowledge to verify and validate command reception.
•
Unique timing mechanisms to handle network congestion
Network Formation
A Tinymesh™ Multi-hop Wireless Mesh Network is self-forming, created by Gateway units starting to
invite Routers and End Devices within RF range to join in the network. A Router joins the network after
verifying the invitation, and immediately starts inviting new nodes to join. Within seconds of powering up
the Gateway, a large network may be created automatically.
Gateway and connected Router devices send periodic beacon packets to indicate presence and
availability for connection. Tinymesh™ beacon packets, referenced as HIAM packets, contain
information of device address (UID), System Identity (SID), Radio Frequency Channel and device
Network Level (Hop Level).
Routers and End Devices receive and evaluate connection alternatives by comparing hop level- and
received signal strength of HIAM packets on selectable time intervals (Connect Check Time)
Self-healing
Devices in Tinymesh™ networks continuously evaluate alternate connections by comparing the hop
level and signal strength of received HIAM packets. In cases where the primary communication link
becomes unresponsive, the device will automatically change to the alternate routing if such routing is
available.
If the alternate routing is also unresponsive, the device will enter a state where it searches for new
routing possibilities.
Data received by the device, and event data generated by the device will be stored in the internal device
buffers until a valid connection has been established.
