Ultra-Compact, Low-Power-Consumption Cellular LPWA Modules, Enabling All Kinds of Internet Connections (Part 1 of 2)

Demand for IoT Devices That Can Collect Data over a Wider Range

We want to build a society that runs smoothly and efficiently based on data; one where people live thriving and healthy lives through data and where data is fully utilized for running valuable businesses. Companies and governments around the world are working to build and use new information systems to make this a near future reality. Together with people, goods, and money, the data that we generate every day in business and in our daily lives has become one of the management resources that drive our lives, business, and society.

Recently, the Internet of Things (IoT), which connects all types of things to the Internet, has made it possible to collect not only data generated in the virtual world, but also data generated in various locations in the real world in great detail. There are already examples of IoT devices equipped with sensors and communication functions installed in various locations on factory production lines, in offices, and in homes to help predict failures and improve production efficiency by understanding the status of equipment and facilities in operation.

However, compared to data collection within a specific area of 20 to 30 square meters, such as inside a factory, there were challenges in collecting data from a wide area of several square kilometers, which is required for automatic meter reading for smart meters and monitoring of social infrastructure such as roads and bridge supports. This is because there was no wireless communication technology suitable for use in IoT devices that could be used to wirelessly connect over long distances.


For data collection within a specific area, existing short-range wireless technologies, such as Wi-Fi and Bluetooth®, can be used for PCs and other information devices.  Small, low-powered communication modules incorporating these wireless technologies are readily available, making it relatively easy to create compact IoT devices. On the other hand, the above-mentioned IoT devices could not be used to collect data over a wide area, and so the only available choice was to use mobile communication technology for mobile phones, which consumes large amounts of power. However, because it is assumed that the devices will be used in places where frequent recharging is not possible, large-capacity batteries are required to provide sufficient power for practical usage, resulting in larger device sizes.

Cellular LPWA -- Extremely Easy to Use for Wireless Communications for IoT Devices

Commercial services for cellular LPWA (Low Power Wide Area), a wide area wireless communication technology for IoT devices, began in 2018 to open up potential uses for IoT devices that had been left out due to lack of an appropriate wireless technology.

Cellular LPWA is based on LTE, a communication method for smartphones and other devices that features wide area coverage, and is designed to dramatically reduce power consumption by reducing the data transfer rate and frequency of communication. These low data transfer rates do not allow for the transfer of video data. However, the transfer rates are fast enough to transmit data on vibrations for assessing how old a road is, the temperature of a paddy field, which is essential for managing the growth of rice, and the locations of share cycles. In fact, the low power consumption provides a noticeable improvement in convenience, such as by enabling many years of use on batteries.

Cellular LPWA has the potential to expand the use of IoT devices, but there are hurdles to be cleared in order to accelerate their adoption. Like Wi-Fi and Bluetooth®, an ultra-compact, low-power wireless communication module that can be embedded and installed in any device or location is needed. Murata Manufacturing Co., Ltd. ("Murata" below) has developed one of the world's smallest cellular LPWA modules by applying its technology and expertise gained through the development of many wireless communication modules. At the same time, we collaborate with providers and chip manufacturers to develop and provide modules that ensure reliable connectivity to the Internet without the need for user specialized knowledge of wireless communications.

Murata's Cellular LPWA Modules Drive Development of Valuable IoT Devices

The value of IoT devices is enhanced by their ability to be used in environments where data cannot be easily retrieved. For this reason, it is extremely important to develop IoT devices having a compact housing that can be installed anywhere and where the number of required battery changes and recharges are minimized. Murata develops and provides high-quality, ultra-compact, low-power-consumption cellular LPWA modules that meet these requirements. We asked the engineers involved in the development of cellular LPWA modules about the usage scenarios they envisioned for cellular LPWA modules during development, as well as the strengths of Murata's modules and their actions in the product development process.

From left to right: Fujiwara (Manager), Hyogo (Manager), Kawanaka (Business Development), and Oh (Business Development)

Realization of Long-Distance Wireless Communication for IoT Utilizing Existing Mobile Phone Base Stations

--What are the potential applications of cellular LPWA as a means of transferring data collected by IoT devices to the cloud?

First, I would like to talk about LPWA's positioning in the market. Up to now, IoT devices have had to use mobile phone service for applications that required data transfers over long distances, such as over 1 km. However, due to the high cost and high power consumption, this means of communication was not feasible for all applications. LPWA is a wireless communication technology that was created to solve these issues.

There are two types of LPWA: cellular LPWA, which uses mobile phone base stations, and non-cellular LPWA, which mainly uses its own access points (Table 1). Of these, cellular LPWA has the advantage of being able to easily deploy a global network by using the communication networks of major telecommunications carriers. It also offers a wider coverage area than non-cellular, as well as greater communication stability and security. This makes it suitable for smart cities, logistics systems, and cross-country data collection.

There are two standards within cellular LPWA: LTE Cat. M1 (LTE-M) and NB-IoT. LTE Cat. M1 features excellent mobility and low latency, as well as a maximum data transfer rate of 1 Mbps (theoretical), which is the fastest among LPWA services. It is suitable for applications such as tracking, emergency equipment, and wearables. NB-IoT, on the other hand, features low cost, low power consumption, and large scale connectivity. 
It is suitable for applications that handle a small amount of information, such as automatic meter reading for smart meters.

Ultra-compact Size and Low Power Consumption That Is Second to None

--What features does Murata offer in its wireless communication modules for cellular LPWA?

Murata provides high-quality cellular LPWA modules that comply with national and regional radio laws and are carrier-certified. We offer modules that enable usage with peace of mind in all aspects of communication stability, reliability, security and mobility. Also, we are proud to be second to none when it comes to ultra-compact size and low power consumption.

--What benefits do the ultra-compact sizes of cellular LPWA modules bring to IoT devices?

Among our developed cellular LPWA modules, the Type 1SC, which is encapsulated in a resin package, features an ultra-compact size of 11.1 mm x 11.4 mm x 1.4 mm. Both the Cat. M1 and NB-IoT standards are supported in this single product, and the area ratio is less than half that of a typical compact module*1. When modules can be miniaturized to this level, they can be used in wristband wearable devices for health care and medical applications, tracking devices to ensure traceability in logistics, or embedded in share cycles to track movement.

*1: Compared to the 18.0 mm x 16.0 mm x 2.0 mm LPWA module

--What are the technical hurdles in miniaturizing the module?

If it was simply a matter of mounting small components or drawing a fine wiring pattern, it would not be so difficult. However, the smaller the size of a wireless communication module, the more subtle differences in characteristics and blurring of patterns have a significant impact on the overall characteristics and performance of the entire module. Moreover, because cellular LPWA has higher output than Wi-Fi and Bluetooth®, it tends to be more challenging to tune for radio law compliance and carrier certification.

For more than a decade, Murata has been accumulating expertise in miniaturizing communication modules and developing cellular modules. There are many suppliers with experience in developing Wi-Fi modules, but I believe there are only a few manufacturers that have the expertise to miniaturize cellular modules.

Lower Power Consumption for More Than 10 Years of Operation Without Battery Replacement

--So what benefits does the low power consumption of modules bring to IoT devices?

IoT devices are not always installed in places where the batteries can be changed and recharged frequently. In fact, IoT devices that can collect data from places where people cannot easily enter are even more valuable. Designing modules that consume less power will enable a longer battery life and easier operation of the IoT devices.

However, reducing power consumption while achieving the communication stability, reliability, security, and mobility required for IoT devices is not easy. Simple communication technologies can be used to implement lower power consumption, but the use of complex communication technologies is essential for providing high-quality modules. It is a challenge for us to find ways to design software and hardware to reduce power consumption.

--What types of technologies have been used to achieve low power consumption?

LTE Cat. M1 and NB-IoT have a technology to reduce power consumption called eDRX*2 or PSM*3. Murata's cellular LPWA modules themselves are also designed with low power consumption in mind. The current consumption in standby mode can be reduced to Typ 3.5 μA, which enables 10 to 15 years of operation without battery replacement*4.

*2: eDRX is an abbreviation for extended Discontinuous Reception. This technology is designed to lower power consumption by reducing the number of times that signals will be received while in standby.
*3: PSM is an abbreviation for Power Saving Mode. This technology reduces power consumption by receiving signals only during limited time slots.
*4: Assumes that an application sends sensor data once a day

Moreover, the communication quality and power consumption during usage are not determined solely by the quality of the module alone. It is extremely important to tune the modules so that the entire system, including the communication infrastructure, runs smoothly. Working as partners in close collaboration with carriers that provide cellular LPWA connectivity services, Murata is jointly developing a communication platform that balances high communication quality and security levels with low power consumption at the system level.

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