Wireless Communication LSIs Compatible
with the Wireless M-Bus Standard for Smart Meters in Europe    ML7406

LAPIS Semiconductor Co., Ltd., a ROHM Group Company, has recently developed a wireless communication LSI compatible with 868MHz Wireless M-Bus ^*１, the European smart meter communication standard. Signal processing functions required for each mode are built in, reducing microcontroller load by about 20% and contributing to lower power consumption of the entire system along with longer operating time and reduced maintenance for battery-operated smart meters.

In recent years, efforts to establish smart meters have begun in several countries. The 868MHz band Wireless M-Bus transmission method, which is likely to become popular in Germany and the surrounding countries and ultimately adopted as the mainstream communication method in Europe, has 3 modes. Signals must be discriminated differently for each mode based on the operating function. Conventionally, packet processing for discriminating modes and messages was commonly performed by software on the microcontroller side, placing an extremely high load on the microcontroller, resulting in higher power consumption.

The ML7406, which supports the frequency band from 750MHz to 960MHz, is compatible with the ARIB STD-T108^*2 standard in Japan as well as the global standard IEEE802.15.4g, making it suitable for a wide range of fields throughout the world, including smart meters and energy management systems (EMS).

LAPIS Semiconductor, in collaboration with Steinbeis, a major vendor and key member of the group responsible for establishing the OMS (Open Metering System)^*3protocol, developed specifications for hardware-based packet processing and integrated a Wireless M-Bus packet handler into the LSI. The packet handler is designed to perform hardware-based processing of a variety of functions, such as simultaneous standby for interoperability between C and T Modes, automatic discrimination of Format A and B messages in C Mode, and address filtering that automatically distinguishes whether packets are intended for this or other devices. As a result, microcontroller operating rate is reduced by about 20% compared with conventional software-based systems, significantly cutting device power consumption.

LAPIS Semiconductor can supply sample software and C source code that include all of the T, C, and S Mode functions compatible with EN113757-4:2011 in the Wireless M-Bus protocol stack. In addition, an industry-standard OMS-compatible protocol stack that can be used without modification in OMS-based meters, along with Wireless M-Bus protocol analysis software, can be licensed from Steinbeis.

The 868MHz ML7406 joins the ML7344E, which is compatible with the 169MHz (N Mode) and 433MHz (F Mode) bands, completing LAPIS Semiconductor’s lineup for the Wireless M-Bus standard and ensuring compatibility with smart meter applications throughout Europe.