Silvanet Mesh Network

The Silvanet Mesh Network uses LoRa in the PHY layer and LoRaWAN for the Mesh Network.

Overview

The Silvanet Mesh Network consists of any number of Mesh Gateways that forward messages from sensors and other Mesh Gateways from deep within forests to one or more Border Gateways. As forests may cause interference with mobile network coverage, the Dryad Mesh Network allows for large-scale off-grid deployments.

Dryad's solar-powered Silvanet Sensors are directly attached to trees within the forest to monitor air composition using ultra-sensitive gas sensors. The gas sensors detect fires using embedded AI (Artificial Intelligence). Information about the environment is sent to the Silvanet Cloud via Dryad's large-scale IoT Mesh Network.

The Silvanet devices use the long-range, low power LoRa modulation in the Physical layer while the Silvanet Mesh network uses LoRaWAN to manage communication between Silvanet devices. LoRaWAN uses frequencies based on country-specific regulations.

Updates to device firmware uses LoRaWAN to distribute updates over-the-air to all Silvanet devices in a Site simultaneously (FUOTA).

LoRa

LoRa is implemented in the Physical (PHY) Layer to provide a long-range communication link between Silvanet's LoRa-enabled devices. The key advantages for using LoRa is its low power usage and long range. It is ideal for Silvanet sensors and gateways as these devices send small amounts of data over long distances every two hours (under normal conditions). This allows the devices to operate using solar panels.

LoRa translates data from the MAC layer into radio frequency (RF) signals using Chirp Spread Spectrum (CSS) modulation. LoRa networks can achieve a maximum throughput of 50 Kbps (100 bytes/min in normal conditions). Additionally, it is approved as a standard for Low Power Wide Area Networking (LPWAN) by the ITU (International Telecommunication Union). As it operates in the license-free sub-gigahertz bands (such as 915 MHz, 868 MHz and 433 MHz), it is subject to interference and retransmissions.

LoRaWAN

LoRaWAN is a Medium Access Control (MAC) Layer protocol that manages communication between gateways and sensors in the Silvanet Network. It is a software built on top of LoRa hardware and defines, amongst other things, when data packets are transmitted and the format of those messages.

Each node in a LoRaWAN network contains its own unique Device ID.

Silvanet Mesh Gateway and LoRaWAN

The proprietary Silvanet Mesh Gateway uses LoRaWAN to enable large-scale deployment of Silvanet devices in the challenging environment of forests where leaves, trees, hills and topology often inhibit radio waves. In these types of environments, the range of traditional LoRaWAN gateways is very limited which prevents them from sending and receiving messages deep into forests.

Silvanet Border Gateways and LoRaWAN

Silvanet Border Gateways use LoRaWAN to communicate with Mesh Gateways (or directly to sensors if they are within range). The Border Gateway forwards messages from sensors and Mesh Gateways to the Silvanet Cloud over the Internet using LTE-M mobile radio, fixed line (Ethernet) connectivity or satellite connectivity.

Border Gateways are responsible for transmitting messages to all devices in the Silvanet Mesh Network for firmware updates using FUOTA.

FUOTA

The Silvanet Cloud sends ML Model and firmware updates to all sensors in a Site using Firmware Update Over the Air (FUOTA). LoRaWAN supports FUOTA and End-to-End 128-bit AES encryption. FUOTA is a standard for distributing firmware updates using unicast or multicast. Its greatest benefit is delivering updates over the air to many devices at the same time in an efficient and secure manner.

Firmware update times are dependent on strength of device communication as well as supercapacitor energy storage levels.

LoRa frequency bands

• Europe: 868 MHz

• North America: 915 MHz

• Asia: 433 MHz

Sensor frequency channels - EU

Sensor frequency channels - US

Max radio frequency power - EU and US

Maximum radio frequency power transmitted (Tx) in frequency bands in which the sensor operates (EU and the US):

• EU Max Tx power: 25 mW EIRP

• US Max Tx power: 25 mW EIRP

LoRa Frequency bands (MHz) - select countries