User's Guide

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Figure 4 – beacon timing, synchronized
The Beacon Event is divided into timeslots. When a node transmits its Beacon, it
randomly selects between the available timeslots. During the Beacon Event each node
will listen for the full duration of the Beacon Event, only interrupted by the time when it
transmits its own beacon. In dense networks with many nodes within radio range, the
nodes will skip beacon transmissions randomly to further decrease the likelihood of
collisions. This approach ensures that 100’s of devices can operate within radio range of
each other.
Once the network is created, the beacon transmissions are in theory no longer needed
provided that the network is static and no new nodes join the network. Beacon Events
do however continue to occur in order to ensure that when the topology changes –
either because nodes physically change location, or because radio links are broken due
to noise or obstructions – the nodes in the network can discover the nodes within radio
range. This also ensures that if two sections of the network become disjoined, they can
re-join once within range of each other again.
The period of the Beacon Event is user configurable, and can be tuned to the desired
rate of which the network shall be able to detect new devices. In most configurations
where static topologies are used, a rather slow setting can be used to conserve energy.
3.3.2.2 Scheduled Data Transmissions
In addition to the Beacon transmissions, each node also transmits Scheduled Data.
Scheduled Data is the backbone in the NeoMesh network architecture, and serves a
number purposes; to keep neighbouring nodes in synch, transmit payload data when
needed, create and maintain routes in the network and to keep nodes logically
separated in super dense networks.
When a node transmits its Beacon, it includes information about the time until it plans to
transmit Scheduled Data next time. This allows neighbouring nodes to allocate a wake-
up timer to wake the node from a low power mode and listen to the Scheduled Data
Transmission of the node, and by doing so becoming a neighbour to the node.