LoRaWAN, Wi-Fi, ZigBee, and LPWAN are wireless protocols used by IoT and IIoT devices.

Low-Power Wide-Area Network (LPWAN) is a wireless technology specifically developed for Internet of Things (IoT) connectivity and machine-to-machine (M2M) communications. As Figure 1 illustrates, LPWAN enables a diverse range of applications.

This article reviews the key advantages and limitations of LPWAN, comparing it with short-range wireless technologies such as Wi-Fi, Bluetooth Low Energy (BLE), and ZigBee. It also explores various LPWAN protocols, including Long-Range Wide Area Network (LoRaWAN) and Long-Term Evolution for Machines (LTE-M), highlighting specific use cases and applications.

Advantages of LPWAN protocols

Many IoT devices are equipped with Wi-Fi, BLE, and ZigBee radios. These short-range wireless protocols can’t, however, efficiently or cost-effectively support all use cases, particularly ultra-low power or expansive IIoT and M2M deployments.

In contrast, cellular and non-cellular LPWAN protocols (Figure 2) efficiently transmit data with minimal energy consumption over distances spanning 2 km to 1,000 km.

Additionally, LPWAN radio modules, such as those in LoRaWAN devices (Figure 3), consume less power than their short-range counterparts. They consume only tens to hundreds of milliwatts during transmission and enter deep sleep modes when inactive, consuming just a few microamps.

Handling small data payloads (10 bytes to 1,000 bytes) at speeds typically up to 200 kbps, non-cellular LPWAN protocols operate in unlicensed frequency bands. These span 863 MHz to 870 MHz in Europe, 902 MHz to 928 MHz in the US, and 920 MHz to 925 MHz in Japan, all within the Industrial, Scientific, and Medical (ISM) spectrum. Cellular LPWAN protocols use licensed spectrum allocated by carriers, often overlapping with existing LTE and 5G bands.

LPWAN vs. Bluetooth LE, ZigBee, and Wi-Fi

Most LPWAN protocols can’t support bandwidth-intensive applications like video streaming or large-scale, rapid data transfers. LTE-M offers higher data rates for Voice over LTE (VoLTE) in enterprise and industrial deployments.

While LPWAN radios facilitate reliable two-way communication, some implementations are prone to latency and transmission delays. This limits their effectiveness for real-time control applications that demand rapid, large data transfers and low or ultra-low latency. Despite these limitations, LPWAN excels in large-scale, low-bandwidth deployments requiring long-range communication and minimal power consumption, such as networks of distributed devices intermittently transmitting small data packets.

In contrast, Wi-Fi, Bluetooth LE, and ZigBee don’t efficiently scale for continuous, expansive M2M and IIoT connectivity. These protocols, however, are used in many consumer, enterprise, and industrial applications. Wi-Fi, for example, is the preferred option for high-throughput cameras and video doorbells, with Wi-Fi 6, 6E, and 7 implementing features such as target wake time (TWT) and power save mode (PSM) to optimize power consumption.

Bluetooth LE radios are popular for fitness trackers, medical devices, and connected lighting systems. While interference challenges and fragmented profiles have slowed ZigBee adoption, the protocol is still viable for home automation, smart lighting, and environmental sensors.

Key LPWAN protocols

LoRaWAN is one of the most widely implemented LPWAN protocols deployed across multiple verticals. Operating on chirp spread spectrum (CSS) modulation within unlicensed frequency bands, LoRaWAN devices communicate directly with gateways, which forward data to central servers.

Secured with AES-128 encryption, the popular protocol delivers data rates between 0.3 kbps and 27 kbps. Transmission ranges typically span up to 10 miles (15 km) in rural areas and approximately 0.6 to 1.2 miles (1 to 2 km) in urban environments. Depending on usage patterns and transmission frequency, LoRaWAN devices can achieve years of battery life under optimal conditions.

Additional LPWAN protocols include:

• Sigfox: A narrowband, non-cellular technology optimized for mass IoT with low data rates. Operating in ISM radio bands, Sigfox offers broad transmission ranges and low operational costs. Devices broadcast messages to multiple base stations, with an average of three stations receiving each transmission. Targeting low-bandwidth applications, Sigfox ensures long battery life and minimal device cost through simple hardware components and low-power semiconductors.
• NB-IoT: A cellular-based LPWAN optimized for low-bandwidth IoT applications in dense urban environments. Operating with 180 kHz channel widths, it provides data speeds of up to 30 Kbps (downlink) and 60 Kbps (uplink), featuring optimal indoor penetration, minimal interference, and long battery life.
• LTE-M/CAT-M1: A cellular-based LPWAN running on existing LTE infrastructure, with data rates up to 1 Mbps. LTE-M facilitates real-time, low-latency communication, ensuring reliable mobile devices and wearables connectivity. While LTE-M consumes more power than NB-IoT, it offers a balanced trade-off between performance and efficiency for frequent data transmissions. As 5G networks expand, LTE-M will continue operating alongside NB-IoT, benefiting from improved scalability and coverage.
• Weightless: This is an open-standard LPWAN designed for the IoT. It operates primarily in unlicensed sub-1 GHz frequencies and accesses licensed spectrum through Weightless-P. Developed in partnership with ETSI and managed by the non-profit Weightless SIG, this protocol offers flexible deployment options and enables diverse use cases through its open-standard approach. 

Use cases and applications

LoRaWAN
Delivering low-power, long-range communication, LoRaWAN is ideal for smart electricity grids, water meters, and precision agriculture sensors that monitor soil moisture and crop health. In parking garages, LoRaWAN sensors only detect and report open spaces when vacated, potentially enabling years of operation through deep sleep modes and energy-efficient transmissions.

Sigfox
Sigfox excels in asset tracking and environmental sensing deployments and offers minimal data usage and low operational costs. The protocol allows companies to efficiently track shipping containers, rental bikes, or industrial equipment in transit by transmitting small bursts of location data over wide areas. In environmental monitoring and weather stations, Sigfox-equipped sensors collect air quality data and other crucial metrics from remote locations, ensuring long-term functionality without frequent battery replacements.

NB-IoT and LTE-M
These LPWAN protocols facilitate many crucial applications by supporting frequent data transmissions and low-latency communication. NB-IoT, for example, is used in smart buildings for HVAC control, secure management of battery-powered smart locks, and connected lighting systems. In smart cities, NB-IoT supports connected streetlights and grids, monitoring and optimizing energy distribution for key urban infrastructure.

With real-time capabilities, LTE-M enables IIoT deployments such as machine monitoring, where continuous data transmission is essential for fault detection. LTE-M radios also support fleet tracking solutions and specialized wearable medical devices.

Weightless
Weightless provides flexibility and low power for IoT deployments, targeting smart city applications and infrastructure management. It enables connected lighting systems, waste management sensors, and air quality monitors. Weightless also supports real-time alerts and remote diagnostics for smart utility monitoring systems, such as water pipelines and electrical grids.

Conclusion

LPWAN radios, explicitly developed for IoT and M2M applications, facilitate a broad range of use cases across multiple industries. Offering distinct advantages over Wi-Fi, Bluetooth LE, and ZigBee, LPWAN transmits data efficiently with minimal energy consumption over short and long distances. Cost-effectively meeting the specific demands of diverse applications, LPWAN spans cellular and non-cellular protocols, from LoRaWAN and Sigfox to NB-IoT, LTE-M, and Weightless.

References

A Brief Guide to Low Power Wide Area Network (LPWAN), Velos
What is LPWAN and Types of LPWAN Networks, AmbiMat Electronics
What is LPWAN?, Soracom
Which LPWAN Protocol Do You Need?, Symmetry Electronics
LPWAN as a Communication Base for IoT, PandoraFMS
Top 3 Benefits of LoRa and Other LPWAN IoT Protocols, Abracon