LPWAN network: fast and efficient technology
The LPWAN network is designed to transmit small amounts of data over long distances while ensuring low energy consumption. This capability is enabled by simplified network architectures, reduced bandwidth, and optimized communication cycles.
This “minimalist” design allows certain LPWAN devices to achieve battery life of several years, or even more than a decade. The goal is not to transmit large files (such as videos) or to perform massive data transfers, but to periodically send information such as battery levels, geographic positions, or temperature.
Also read: LPWA networks, Low Power Wide Area
The two main families of LPWAN networks
LPWAN technologies fall into two main categories: non-cellular networks like LoRaWAN or Sigfox, and cellular networks like NB-IoT or LTE-M.
Non-cellular networks
The Sigfox network, a pioneer in the field, relies on proprietary technology operating on unlicensed frequency bands, such as 868 MHz in Europe. It is characterized by ease of use, very low cost, and very limited throughput. This technical choice imposes significant restrictions: a device can only send a few messages per day, each containing a limited number of bytes. This network is suitable for applications with very low data requirements, such as water meter readings.
LoRaWAN offers more flexibility. Based on unlicensed frequency bands, it allows operators to deploy their own private networks. This open-source technology offers a slightly higher throughput than Sigfox, as well as greater flexibility in network device configuration. This last characteristic makes it a preferred solution for many smart city objects and connected agriculture.
Also read: Smart farming: definition and impact of the Internet of Things
Cellular networks
Cellular LPWAN networks leverage existing 4G and 5G infrastructures. NB-IoT (NarrowBand IoT) is designed to operate on licensed frequency bands, which offer great reliability and optimal penetration into buildings. It is the preferred network type for fixed or buried sensors like those used in water or electricity meters.
The LTE-M network is even more efficient than NB-IoT, as it allows for better latency, higher throughput, and supports mobility. It is particularly used for objects in motion such as vehicle fleets or localization equipment.
Technologies adapted to usage
The LPWAN network necessitates balancing several criteria: throughput, range, autonomy, security, mobility, and cost.
For example, a temperature sensor placed in a field has different requirements than a GPS sensor placed on an international transport truck. The temperature sensor can leverage LoRaWAN for local coverage and autonomous deployment. The GPS sensor requires an LTE network, which is better suited for ensuring smooth communication on the move. Finally, a sensor placed on a buried or basement water meter would likely rely on NB-IoT technology for its ability to penetrate walls and obstacles and for its sleep functionalities.
Energy challenges at the heart of IoT
The autonomy of devices is one of the major challenges of the Internet of Things. Cellular LPWA networks have introduced two major mechanisms to optimize battery life: eDRX (extended Discontinuous Reception) and PSM (Power Saving Mode).
The eDRX mode allows a device to remain dormant for longer periods by spacing out its network listening intervals. This way, energy consumption is reduced, but the device remains reachable, even if response times are extended. This technique offers an interesting compromise for devices that need to receive non-urgent commands.
PSM mode is even more economical than eDRX mode, as it allows the device to enter dormancy, completely interrupting its network communication. It becomes unreachable except at predetermined times. This mode is preferred for devices that do not need to be remotely queried and only need to send data occasionally. Thanks to this very economical mode, some devices can operate for several years, even a decade.
In summary, cellular LPWA networks (NB-IoT, LTE-M) are distinguished by their wide coverage, reliability, and high-level security, making them an ideal solution for connected mobile objects. Conversely, non-cellular LPWA networks are often preferred for localized and controlled uses due to their simplicity of implementation and low energy consumption. Each technology addresses specific needs, and their complementarity allows for a wide range of use cases in IoT.
Objenious: your partner in realizing IoT projects
Objenious, a Bouygues Telecom brand dedicated to IoT, offers tailored support based on your project needs. NB-IoT, LTE-M, cellular IoT: find the technology that best meets your requirements.