2022/07/15
IoT communication technologies require networks that can cover wide areas with low power consumption. LPWA is a type of wireless network technology suitable for this IoT era. This article will explain the features and types of LPWA, and then introduce the LPWA products offered by Contec.
LPWA stands for “Low Power Wide Area,” a collective term for wireless communication networks that can cover wide areas with low power consumption. Generally, an LPWA can transmit data over longer distances (several kilometers to several tens of kilometers) than wireless LAN or Bluetooth, and has the advantage of lower power consumption than cell phone mobile communications.
When using a smartphone, many people may switch wireless communication depending on the situation. For example, switching of wireless communication may be considered in the following cases.
The reason for switching usage between communications is that each system has the following characteristics.
When using a smartphone for data communication, it is more convenient to use high-speed, high-volume communication. Because of the demand for this communication, wireless communication networks have also developed. However, in the field of IoT, where various devices and sensors are connected to the Internet, different performance may be required.
For example, let’s assume that temperatures at various locations throughout a plant’s wide grounds are to be collected by data communication. In this case, the communication distance is too short for Bluetooth or wireless LAN to cover the entire site. Mobile communications can cover a wide area, but power consumption is a bottleneck.
Temperature sensors may need to be battery powered in areas of the site where no power supply is available. Higher power consumption requires more frequent battery changes. Unlike images and audio, temperature data is small in both data volume and number of transmissions.
For these types of applications, the ability to communicate with low power consumption is more important than the communication speed and data volume. And so, using a low-power LPWA can reduce the required number of battery changes for enabling use over longer periods of time. LPWA was developed as a wireless communication network with a long communication range and low power consumption for achieving wide-area coverage and long-term data communication required for IoT.
LPWA can be broadly divided into cellular LPWA and non-cellular LPWA.
Cat.M1 is a cellular communication system that uses LTE band frequencies, and its main feature is that it enables high-speed communication at 1 Mbps upstream / 1 Mbps downstream, which is faster than other LPWA communication systems. Its transmission distance ranges from several kilometers to a dozen kilometers, enabling wide-area coverage. The implementing organization is the 3GPP (3rd Generation Partnership Project), a standardization organization made up of national and regional organizations.
Cat.M1 can use the networks of major telecommunications carriers, which require a license, and thus provides a wider range and more stable communications than non-cellular communication systems. However, some disadvantages are that power consumption and costs are high. This communication system is effective for relatively large data transfer volumes.
The “NB” in NB-IoT stands for “Narrow Band” and, like Cat.M1, it is a licensed cellular communication system implemented by the 3GPP. Because it uses a portion of the LTE band frequency (narrow frequency), it is a lower cost and slower transmission speed communication system than Cat.M1. The transmission speed is approximately 63 kbps upstream / 27 kbps downstream, and its transmission distance ranges from several kilometers to a dozen kilometers.
NB-IoT specifications are even more IoT-oriented than Cat.M1, and NB-IoT is expected to reduce costs when using a large number of devices that require small amounts of communication.
Sigfox is a non-cellular LPWA communication system implemented by the French company Sigfox. In Japan, it uses the 920 MHz frequency band. Although the transmission speed is low at 100 bps upstream / 600 bps downstream, it can cover a wide transmission distance ranging from several kilometers to several tens of kilometers, and can be used at low cost and low power consumption.
The upstream data volume is limited to 12 bytes per transmission and the number of communications is limited to 140 times per day, making it suitable for IoT with low communication volume and number of transmissions, such as smart meters.
Although this is an unlicensed band that does not require a license to install base stations, only one Sigfox network operator per country actually installs base stations, and in Japan, Kyocera Communication Systems (KCCS) installs base stations and provides communication services.
LoRa is a standard developed by Semtech that specifies the physical layer of LPWA, and its name is derived from “Long Range.” The frequency band of this system in Japan is 920 MHz. The transmission speed is 0.3 kbps upstream / 50 kbps downstream, which is slow but is still faster than Sigfox. The transmission distance ranges from several kilometers to a dozen kilometers and can be used at low cost and low power consumption.
It is a license-free, unlicensed band, and is available for installation and use at self-operated base stations, whereas Sigfox always uses infrastructure provided by a Sigfox network operator. Since only the physical layer is specified by LoRa, communication between LoRa base stations and LoRa devices is implemented independently by each company and is not mutually compatible.
While LoRa specifies only the physical layer, LoRaWAN is a standard specified by the LoRa Alliance as a wireless communication network. Since it is specified as a wireless communication network, LoRaWAN base stations and LoRaWAN devices from different companies can communicate with each other.
In addition to installing and using their own base stations, users can also use LoRaWAN base stations installed by service providers. To use LoRaWAN base stations installed by a service provider, a usage contract with the service provider is required.
Contec offers products that support the LoRa standard and wireless products that use the sub-1GHz frequency band.
CPS-COM-1QL is an outdoor communication module using the LoRa modulation system for LoRa wireless communication modules compatible with our CONPROSYS series of IoT controller devices. It enables wireless communication between IoT controller devices at distances of 10 kilometers and longer.
Contec conducted a communication test for the new product over a distance of approximately 17 km between the Tenran Observatory, located next to the Rokko Cable Line’s Sanjo Station (Hyogo Prefecture), and Kaze Soyogu Oka on Maishima Sports Island (Osaka Prefecture), the result of which demonstrated that stable communication was possible over this distance.
Wireless I/O is available for digital and analog input/output using the sub-1GHz band (920 MHz in Japan) frequency range. Compared to the above-mentioned LoRa standard, the communication distance is shorter (about 1 km), but the system can be built more easily.
Gateway (Master unit)
Analog input (Slave unit)
Isolated digital input/output (Slave unit)
In P2P mode, two digital I/O terminals can be placed opposite each other and the signals transmitted through the terminals. This enables the input of one device to be directly applied as the output of the other device even without a master unit, PC, or PLC at distances of up to 1 km.
For details on the wireless I/O series
Contec’s LPWA products can be used in a variety of situations by combining them with the CONPROSYS series, which offers a wide range of products for IoT. Please contact us at Contec to find the optimal IoT solution for your needs.
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