Wireless star network at 868 MHz / 915 MHz
A highly efficient 2-way wireless IIoT network supporting long range, very low power, and high density networks
RIIoT™ (Radiocrafts Industrial Internet of Things) is an RF system designed to meet the sensor and actuator connectivity requirements for the Industrial IoT. The RF protocol is the IEEE802.15.4 g/e standard with RIIoT™ additions. RIIoT™ includes an Intelligent C-programmable I/O (i:zi), which makes it possible to directly interface to any sensor or actuator. RIIoT™ does not require any license or subscription fee.
Radiocrafts’ commitment to making connectivity easy for network designers working across a variety of radio frequency networks was the driving motivation for developing the RIIoT™ additions to IEEE802.15.4 g/e standard.
The RIIoT™ system consists of the following parts:
- The RIIoT™ Net Controller
- The RC1880(HP)-SPR, the RIIoT™ leaf node module
- The RC1880(HP)-GPR, The RIIoT™ Gateway module
- The RC1880(HP)-GPR-GW, the RIIoT™ gateway dongle
- The RIIoT™ development tools
- A commercially off the shelf (COTS) Linux Gateway
Support for the cloud
The RIIoT™ Net Controller, is a provided Linux middleware that is part of the RIIoT™ network solution and integrates in a Linux Gateway. It makes it easy to both manage the RF network and route data to user gateway applications or the Cloud.
The controller provides a socket interface for user applications, making RIIoT™ compatible with any platform and user application written in any language. Data from RIIoT™ networks are forwarded to user applications as JSON objects that are easily parsed and forwarded to the Cloud.
RIIoT™ will operate without the RIIoT™ Net Controller, but with reduced functionality in terms of cloud support and network monitoring. See the RC1880(HP)-GPR description.
Long RF range
RIIoT™ RF is based on the IEEE802.15.4g/e standard with RIIoT™ additions in the application layer. RIIoT™ RF creates a robust long-range network, with a range sufficient for most industrial applications.
The following table shows calculations of RF ranges for various networks. The RF ranges were calculated using an empirically derived formula that is an industry standard; namely, “the Free Indoor Model,” which is also applicable for the outdoor urban environment:
LP = Path loss
R = Range
Path loss is given by LP = P0 – n*10*log10 R
PO (Path loss at 1m ) = 20 * log(300/4*PI*frequency)
We use n=3.6 as typically used for factories with an obstructed line of sight. See our application note AN021 for further details on the model.
Tx power is limited to 14 dBm for 868 MHz, 27 dBm for 169 MHz, and 7dBm for 2.4Ghz in these calculations.
RIIoT™ RF has a practical range of over a kilometer.
High node count
RIIoT™ networks support a high node count per gateway driven by the short transmit pulse time and the Listen Before Talk (LBT) feature on MAC level.
- The risk of interference between simultaneously sending nodes is small with short Tx pulses.
- Listen before Talk (LBT) on Mac level makes RIIoT a “Polite Spectrum” device according to the European regulations. This increases the available on air time from 0.1% and 1%, to 2.8%, allowing for more air time than regular ISM band radios that transmits without any prior check if the band is free.
Radiocrafts has done tests with RIIoT™ using 28 nodes sending data randomly every 4 seconds to one gateway. We achieved amazing results having 99.83% good packets received. To be fully compliant to the 2.8% rule, we need to reduce the update rate to sending every 5 seconds, that will also decrease the packet loss slightly.
Frequent Readings/Updates are possible due to the short pulse length in IEEE802.15.4 e/g. This ensures that many messages can be sent during the space of an hour, without violating the 1% duty cycle that is imposed by radio regulations. The RIIoT™ message length (45ms in long range mode) is less than 3% of a LoRaWAN long range message or a Sigfox message.
Long pulse length is a major concern when frequent readings are required in a multi node network, as packet collisions will soon be a problem when the pulse length is long and the node count increases.
Near Real Time Control
RIIoT™ is an excellent network for near real time control applications. RIIoT™ is based on the IEEE 802.15.4 g/e which is a symmetrical wireless communication protocol. The RIIoT™ implementation as a star network means that the delays in the network are short, in the range of 10ms, and predictable. This is ideal for near real time control applications such as manufacturing, environmental control, asset tracking, alarm systems and many more.
Over-the-Air (OTA) firmware updates
Your product will be future-proofed by RIIoT™’s over-the-air updates. OTA updates are possible because of RIIoT™’s two-way communication channel and the module’s internal flash memory.
You can upgrade your RIIoT™ nodes in the field with new sensor/actuator interfaces, new signal processing algorithms, and updated security patches. You can also keep the underlying RF system firmware current using RIIoT™ Over-the-Air updates.
Low current TX/Rx/Sleep
- TX 8.5 mA @ 0 dBm
- TX 19 mA@ 12 dBm
- TX 26 mA@ 14 dBm
- RX 6.2 mA
- Sleep 0.7 uA with crystal based sleep timer running
Short Tx/Rx times
RIIoT™ uses small energy pulses. This is an important network design/cost consideration, since coin cell lithium batteries do not like large pulses of current — making them unsuitable for LPWAN technologies. Longer transmission times used in some LPWAN technologies would need large (e.g. AA cell) lithium batteries, or super-capacitors in order to handle these high current bursts during Tx. But that also significantly increase the cost of the nodes.
The TX signal length for 12 bytes application data is 4.5 ms, which is very short in sub-GHz LPWAN transmission technologies. See the technology comparison below. The total energy transmitted per packet is calculated and the minimum average time between transmissions calculated. This is a measure on how often a sensor can be read on a 500mAh battery if the battery should last years. For a battery-operated system with many sensor readings, this a critical parameter.
Long sleep time
RIIoT™ has no mandatory background communications that would require frequent wake-up. This means that in a smart end node application — where data processing is done in sensor node and RF packets are only sent during alarms — a radio in the sensor node can be sleeping for hours, or even days. Smart end-node applications in RIIoT™ using the Intelligent C-programmable I/O (i:zi) are supported by the RC1880(HP)-SPR leaf node module.
RIIoT™, therefore, is well suited for applications wanting to use low cost coin cell batteries and no costly super capacitors.
RIIoT™ secures data in-flight using AES128-CCM, an encryption scheme that offers confidentiality, integrity, and authenticity assurances. AES128-CCM offers protection against eavesdropping, modification, replay, and impersonations.
Unique Key per Link
A unique AES key is established between each node and the coordinator using Elliptic Curve Diffie-Hellman (ECDH). So even if one node is compromised, data from the rest of the network is still secured.
RIIoT™ users can also opt-in for end-to-end security to encrypt data all the way from the end node to the user cloud application. With end-to-end security, data is protected from eavesdropping or modification even in the gateway that is responsible for routing.
RIIoT™ users can also use a “whitelist” so only approved nodes are accepted into the network. A whitelist requires a verification of the node’s security credentials prior to it joining the RIIoT™ network.
Interface to any sensor or actuator
The Intelligent C-programmable I/O (i:zi) for the programmable node, the Radiocrafts RC1880(HP)-SPR, comes with APIs to read and write to the local interfaces, including UART, I2C, SPI, GPIO and ADC. This flexibility allows the user to integrate to any sensor or actuator or any combination of sensors and actuators.
For RF network reliability, RIIoT™ RF leverages various established techniques that reduce vulnerability to interference, avoid noisy environments, and recover poorly received packets. RIIoT™ RF also has a built-in network monitor that can send alarms when links are malfunctioning.
To avoid noise interference when info is received, the signal length should be as short as possible; RIIoT™ RF achieves this by using 50 or 5 kbps data rates and very low overheads.
To avoid interference so as to hit the open window in the frequency plane, RIIoT™ uses low bandwidth, and good Rx filtering.
Frequency hopping helps to avoid interference as noisy channels are automatically avoided.
“Interference tolerance” is the signal level required to possibly distort a data packet that otherwise would be received OK. A higher interference tolerance number is better than a lower number, allowing a transmitter that causes the interference to be located closer to the RIIoT™ device without interference.
Ack/retry ensures that good data is received but is only possible if the signal length is relatively short, as supported by RIIoT™ RF. It provides a very robust reliable transmission process. If the data is not received, the module will repeat the data until it is received properly. The alternative (less desirable) approach is to initially send more data than may be needed, e.g. send the same data more than once (Sigfox) or add forward correction bits (LoRa). Ack/retry is only possible if the signal length is relatively short, as supported by RIIoT™ RF.
Network monitoring adds reliability as it continuously checks the quality of the network and sends alarms if performance goes down.
The takeaway for industrial RF network designers is that RIIoT™ is well suited for high reliability/QoS types of applications: The probability of interference (in time, frequency, and signal space) is low; RIIoT™ supports frequency hopping; and there are good mechanisms to recover information from a packet loss (Acknowledge and re-transmission).
Symmetrical down and uplink communication
The IEEE802.15.4.e/g supports symmetrical communication which means that messages can be sent at full speed both uplink and downlink. Good bi-directional communication is critical for any control application and also for making firmware Over the Air updates (OTA).
Short time to market
Designed to be very easy to implement, the RIIoT™ system features:
- High quality RF modules that remove most of the RF hardware design issues
- Intelligent C-programmable I/O (i:zi) on leaf-node modules allows the designer to implement a custom application in less than 100 lines of high-level C code
- The RIIoT™ RF protocol, RIIoT™ RF, with built-in features for low power consumption, long range, high reliability, and advanced security
- The RIIoT™ Net Controller, which eases gateway integration and cloud connectivity, monitors the network functionality, and provides for an easy network set-up
- A separate gateway dongle, RC1880(HP)-GPR-GW, interfaces to a Commercial off the shelf (COTS) gateway via USB, making the gateway solution simple to implement, the RC1880-GPR can be integrated in the gateway as an alternative solution.
RIIoT™ provides a complete RF subsystem that can interface to any sensor or actuator, while taking data to and from the Cloud, via a gateway/concentrator, with industrial grade performance. The complete network can be designed and set-up in a matter of days. Cloud connectivity is easily implemented with the RIIoT™ Net Controller using a standard Linux-based gateway with internet access.
The RIIoT™ Parts
RIIoT™ Net Controller
The RIIoT™ Net Controller resides on the network’s gateway. It is part of a Radiocrafts Linux software package, and it’s designed for easy installation on a Linux-based gateway.
The RIIoT™ Net Controller can be easily integrated into a user application through a socket. Data and commands are communicated as JSON objects. The main functions of the network controller are:
- Supporting the set-up of the RF network
- Monitoring the network for broken links, etc
- Managing low-level networking through the RC1880(HP)-GPR module
- Conversion between RIIoT™ RF encoding to JSON data
- Managing over-the-air firmware update of leaf nodes
RC1880(HP)-SPR leaf node module
The Radiocrafts RC1880(HP)-SPR is a programmable RF module that is compatible with IEEE802.15.4 g/e and RIIoT™ RF. In addition to being used as part of Radiocrafts Industrial Internet of Things (RIIoT), the RC1880(HP)-SPR module can also be used as a leaf node in other IEEE802.15.4 g/e RF networks.
The RC1880(HP)-SPR is programmed through an Intelligent C-programmable I/O (i:zi), so users can write their own application code in high-level C language. This programming efficiency is useful for managing sensor and actuators, creating local alarms, doing signal processing, etc.
RC1880(HP)-GPR gateway processor module
Radiocrafts RC1880(HP)-GPR is an IEEE802.15.4 g/e compatible modem module for the gateway/concentrator. The modem module supports RIIoT™ RF and can interface to several hundred RC1880(HP)-SPR nodes.
The RC1880(HP)-GPR module can be used together with the RIIoT™ Net Controller – The Radiocrafts provided Linux middleware that makes it easy to communicate on the RF network. Alternatively, user applications can directly interface with the RC1880(HP)-GPR using the UART.
RC1880(HP)-GPR-GW (Gateway Dongle)
The RC1880(HP)-GPR-GW is a stand-alone gateway dongle that includes the RC1880(HP)-GPR module and a USB transceiver. This dongle can be added to a Commercial Off the Shelf (COTS) Linux gateway with a USB interface, to create a complete RIIoT™ Gateway. The dongle comes with an antenna, a USB cable and a power adaptor. The dongle is certified and ready to be operational.
Read more about the RIIoT™ parts here.
RIIoT™ tools to accelerate your development
RIIoT™ leaf node SDK – A software development kit for programming the RC1880(HP)-SPR leaf nodes. The kit comes with an Intelligent C-programmable I/O (i:zi) with high-level C APIs that allow you to interface to any sensor or actuator, and to implement any data processing and edge intelligence function.
Using less than 100 lines of code, you can write a full application for sensor interfacing and networking. For more complex applications, up to 10K of space is available. The SDK kit comes with a free development environment, a compiler, and flashing tools.
To download the RIIoT™-SDK please click here.
The RIIoT™ Gateway Software Package – includes tools and firmware to set-up a RIIoT™ network with the RC1880(HP)-GPR module and a standard Linux based gateway. The ambition is to make the set-up process as easy as possible, while still maintaining the ability for the user to set up key network parameters to optimize for a specific network’s requirement.
The RIIoT™ Development Kit, RC1880-RIIoT-DK – includes all the hardware needed to start running a small RIIoT™ network from a PC. This allows the customer to test the network capabilities with minimum development resources needed. This is ideal for a first range test in a customer environment.
RIIoT™ Application Notes – Application Notes to help you setup your RIIoT™ Network.
Read more about the RIIoT™ Tools here.