LoRaWAN Solutions from Scratch Challenging
Introduction
Low-Power, Wide-Area Networks (LPWANs) implemented using LoRa protocols becomes LoRaWAN. These protocols define an IoT device network that optimizes the network’s device capacity, device battery life, transmission range, and therefore, overall system cost. LoRaWAN is a communication protocol that works on top of the LoRa physical layer – the RF (radio frequency) part of the communication system. Implementing an LPWAN solution with LoRa & LoRaWAN requires expertise in both the physical and communications realms.
The advantages of LoRa solutions include low-cost, long-range, reliable signal transmission, high volumes of devices per gateway, low network power consumption, license-free band usage, and secure communications. The trade-offs are low data rate and latency (data is not truly real-time), and reliance on a gateway for connectivity where a failure of this hub could mean losing data from multiple devices.
There are many applications where the benefits of LoRaWAN solutions are attractive enough to overlook the development costs and trade-offs. So, what makes development hard? First, let’s consider an end device, such as a sensor.
Physical Implementation
To implement a LoRaWAN communication protocol, you need to have physical devices that operate on it – both end nodes and gateways. Each device needs a LoRa chipset, the required RF components, computing and sensor systems, and power circuitry. You must consider the potential device applications to decide what kind and quality of sensors to use, the type of power source required, and the appropriate antenna and enclosure for your environment. For gateways, you also need to consider the backhaul – how will you communicate the aggregated sensor data and network info to the platform you’ll use to manage devices, store data, and perform analytics.
The physical implementation not only requires considering which components to include, but also, how to package them so that they work properly – for example, temperature sensors need to be placed where they are far enough away from heat sources on the board and exposed to the environment, but also in a place where they are mechanically protected by the enclosure. This design can be a challenge when considering applications that might also require water-proof or explosion-proof containers.
The enclosure design itself is a challenge – in fact, it’s one of the hardest parts of building a device. It requires not only careful design, but also consideration of potential uses. You may be selling them to companies in a wide variety of businesses, from refineries to farms – what will your sensors or gateways be exposed to? How will they be mounted? What physical hazards surround it? What aesthetic is required? Making a mold for such an enclosure is a time and money intensive undertaking, so you need to consider a wide variety of possibilities to maximize the value you get from it and minimize the number of redesigns and specialized variations you may need to create in the future.
Once you have the device details sorted out, it’s time to consider how they will communicate.
Protocol Implementation
Once you have the physical characteristics of your system determined, you can then plan on implementing the LoRaWAN communications protocols. LoRaWAN is a specification only, so it is left to developers to implement it with devices running a LoRa physical layer. This is a complex undertaking and there is no right answer - every developer can have their own implementation of LoRaWAN. There are many aspects that are covered by the protocol and several that are not. The latter are left to the developer to solve, which leads to these variations.
Implementation for the device side of the solution is partially open source, but the server-side is completely up to the developer and, thus, the hardest part of the process. For the devices, LoRaWAN specifies the structure of the physical and MAC messages, MAC commands, end-device activation, and aspects of handling message acknowledgement and retransmission. Details of how to address your devices and provision them into the network are left to you. While the method of communication between devices, network management, and security are defined by LoRaWAN, they need to put in place by the developer. In the case of security, additional steps need to be taken to ensure the confidentiality and integrity of the data being sent.
While there is no way around developing the hardware and protocol if you want to create your own IoT solutions, there are some companies that are providing an alternative to making one from scratch.
A Quicker Solution
While the LoRaWAN framework leaves a lot to the developer, it also allows you freedom to tailor your solution to your specific application and that allows you to be more competitive in your targeted market.
Starting from scratch with a LoRa device means understanding the operating environment and what you need to detect to develop your specifications. It means design, testing, and re-design of the circuitry: integrating the sensors, MCU, and RF ICs. It means programming the firmware for the device per the specific protocol implementation your LoRa gateway is using. That brings us to the LoRaWAN protocol itself: you are given a framework for communications and security, but are left to develop the firmware (and hardware) that implements it.
A faster solution for sensor development, and one that several LoRa solution developers are providing, is using a pre-packaged LoRa module which already integrates the RF, and in some cases the MCU. These chipsets are typically designed to and require a specific gateway implementation which the chipset manufacturer usually provides. Using these chipset modules eliminates the need to implement the LoRa and LoRaWAN protocols yourself and saves you hardware development costs by requiring use of an already existing gateway. Many solution developers will also provide design services for these sensors and, for an organization that needs a large scale wireless sensing solution, this helps keep them focused on their core business (instead of forcing them to become an IoT hardware developer).
At first glance, LoRaWAN implementation may like a simple concept, but it requires expertise in both hardware and software development. And once those steps, and multiple iterations of testing, are done, you can finally prepare for production. A great alternative is to use a pre-existing implementation from a company that allows for custom sensor development with a LoRa-based chipset.
