Dust Networks’ founders started out with a clear vision that remains true today to create an ultralow power network without wires that could be deployed in the harshest of environments, usually fixed locations and over wide distances. It has two product lines: SmartMesh WirelessHART motes and network managers are designed for harsh industrial environments and are compliant with the WirelessHART (IEC 62591) standard, and SmartMesh IP, which provides native IPv6 addressability to every node and is based on 6LoWPAN and 802.15.4e standards.
What sets Dust’s SmartMesh network architecture apart is its work on Time Synchronised Mesh Protocol (TSMP). TSMP includes Time Slotted Channel Hopping (TSCH), a media access layer pioneered by Dust Networks that divides time into ‘slots’ and provides a mechanism to map timeslots to channels with a pre-assigned hopping sequence. TSCH allows the motes to sleep in-between scheduled communication, one of the secrets to its very low power use.
From a design perspective, there’s much to recommend Dust Networks’ technology. Here are five reasons why Dust is a ‘must evaluate’ for any design project that requires a good mesh networking technology:
- Reliability: In SmartMesh, each field device can act as a low-power router for another device’s data packets. This mechanism extends the network range and creates redundant communication paths. Even without line-of-sight between devices, each device has multiple neighbours to whom it can send data, providing the path diversity needed for a reliable network. In addition, by focusing on customers who want to ‘set and forget’ a network, Dust’s products incorporate channel hopping and network healing to ensure reliability for the life of the network.
- Micro-power: SmartMesh offers the lowest power consumption in its class thanks to a synchronised communication protocol that enables deep duty-cycling and high power efficiency. In addition, Dust’s motes are based on Linear’s Eterna SoCs which incorporate battery-free energy harvesting and claim to enable battery powered devices built on them to last up to 8 times longer. On the subject of power, it’s worth noting that a key distinguisher between SmartMesh and Zigbee devices is that every node on the network is a low power, repeating mesh node, so there are no special nodes that require more power.
- Scalability: Because traffic is time slotted, SmartMesh networks have no in-network collisions and scale from a small to a large number of sensors and from low to high density. They also survive the loss of individual devices.
- Resilience against RF interference: A SmartMesh network dynamically identifies mesh hop paths based on constant surveillance of the network and the RF environment, and the time-slotted channel hopping technique ensures that the system always uses the best possible available channel for data transmission, avoiding interference.
- Adherence to open standards: Dust leverages 802.15.4 and is a major contributor to the IETF 6TiSCH working group, a technical committee that is defining an open standard for building and maintaining a TSCH schedule in a 6LoWPAN network, thus adding time-slotted channel hopping into the protocol for the IP-based network. Just as Dust’s TSMP technology is a key building block of the WirelessHART (IEC 62591) wireless standard, the company’s contribution of TSCH know-how to an open standard should give customers confidence that Dust Networks supports an open ecosystem.