User's Guide

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3.3.6.2 FHSS – Frequency Hopping Spread Spectrum
The protocol uses FHSS to avoid noise and to ensure that the radio communication is
not blocked by problems which are typically seen when operating on a fixed frequency,
such as fading and blocking due to other radio communication equipment operating at
the same frequency.
Each time a node is sending its Scheduled Data Transmission (either with or without
payload) it does so at the next channel in the hopping list. The hopping list consists of
15 logical channels, each of which can be assigned to a physical radio frequency. This
means that the network can be configured to use an arbitrary range of radio frequency
channels, either evenly spread in the frequency band, or grouped in sections to avoid
certain parts of the band. Channel 16 is the beacon channel, and is not used as part of
the hopping scheme. The range of physical channels varies from frequency band to
frequency band, and thereby module variant to module variant. The modules are pre-
certified for compliance to EU and US rules, and the available physical channels are
limited to comply with rules in the different regions.
3.3.7 Wireless Encrypted Setup
A NeoMesh node is pre-configured for a particular network. The configuration
parameters can be written to the module through the System API UART.
To ease the deployment of new nodes, and to allow end-users to add new nodes to an
existing network without having to write settings to the module manually, Wireless
Encrypted Setup (WES) is provided as a functionality which allows unconfigured
modules/nodes to be setup for an existing network wirelessly by having another node
who is already part of the existing network announce the network through an Encrypted
WES channel.
The Encryption Key for the WES Channel is separate from the Network ID (also an
encryption key), and is usually the same for a group or a category of modules/nodes.
The WES process requires one node in an already existing network to be setup as a
WES Server. This is achieved through sending a set of commands through the
application API (see integration manual). Once the node is setup as a WES Server, it
begins to send out WES Beacons on the WES Channel, which is encrypted with the WES
key. This means that nodes which do not have the correct WES key cannot be setup for
the particular network.
If an unconfigured node/module is put into WES Client mode (see integration manual),
it will start looking for a WES beacon. If it receives the WES Beacon, it will send a setup
request, along with its UID
2
to the WES server node.
2
Each NeoMesh module is equipped with a 5 byte unique ID pre-programmed at factory level, and non-
changeable