Panasonic Develops a Multi-band Wireless Communication Technology that Supports All Frequency Bands in Wireless Sensor Networks

With Panasonic's technology, advanced M2M wireless networks which cover all wavelengths in wireless communication are possible, making linking devices simpler and realizing a safer and more comfortable life.

Osaka, Japan - Panasonic Corporation today announced that it has developed a new multi-band wireless communication technology that enables low powered stable communication through simple wireless connections between devices of different standards. Devices equipped with this technology will be able to support all the frequency bands of wireless sensor networks[1] and realize energy savings of 30% of the power of conventional single band wireless blocks. These technologies will accelerate the spread of "M2M (Machine to Machine) Sensor Networks[2]" that support cloud-based data exchange without human intervention.

The development combines all of the tuning circuits which had previously been necessary for each frequency band, allowing for a stable connection to the network regardless of the location and the wireless standard of the device. In addition, by detecting the radio frequency component directly, a reduction in the size of the chip and its power consumption has also been achieved. In applications where they power supply can be problematic, sensor network radio powered by batteries have become possible. Through this technology, connecting devices and equipment will become easier, accelerating the development of a new business model for cloud applications.

The developed technology has the following features.

- Supports all frequency bands (400MHz, 900MHz, 1.2GH and 2.4GHz) for IEEE802.15.4x sensor network radio[3] regulations.

- The surface area of the chip which supports multi band is 12% smaller than a conventional single band chip.

- More effective demodulation process introduced to reduce power consumption. The working time is expected to be more than 20 years under typical wireless network operating conditions in the field of smart meters and HEMS applications, with data transmission every 30 seconds with a 1200mAh battery.

This development is based on the following new technologies.

Multi-band technology makes the removal of some inductors on receivers and filters on transmitters that were previously necessary for each frequency band possible through digital assist analog circuits.
Demodulator with direct frequency detection scheme for reducing the circuit size and power consumption of the receiver.

Panasonic holds 25 Japanese patents and 14 overseas patents, including pending applications, for this development.

This result was supported in part by the "R&D of radio communication infrastructure technology using multiband/multimode compatible sensors" of The Ministry of Internal Affairs and Communications, Japan. A part of this technology will be presented at Wireless M2M Expo 2013 at Tokyo Big Sight, Japan on May 8-10.

1. Multi-band technology makes the removal of some inductors on receivers and filters on transmitters that were previously necessary for each frequency band possible through digital assist analog circuits

The undesired 3rd and 5th order harmonics are generated on the power amplifier circuit for transmitting high frequency radio signal. Panasonic has developed a new technology for reducing the harmonics by controlling the phase of high frequency signals. The technology has made it possible to implement a filterless power amplifier circuit compatible with a very wide frequency band without increasing power consumption and chip area by eliminating the harmonics filtered circuits dependent on the frequency. In addition, the traditional amplifier circuits have the inductors constructed of spiral conductors. However multi-band amplifier circuits have inductors for each of the frequency bands they support, so their chip sizes increases. For this problem, Panasonic has developed active inductor type amplifier circuits combining small sized transistors, resisters and condensers, which work as an active inductor in the equivalent circuit which are automatically synchronized with the frequency band by compensating for the device characteristics variations.

The developed low noise amplifier circuits in the receiver have been reduced in size to about 10% of that of conventional single band amplifier circuits, realizing a reduction of about 12% of the overall chip size.

2. Demodulator with direct frequency detection scheme for reducing the circuit size and power consumption of the receiver

In the past, FSK[4] demodulation circuits were used on receiver signal processing of sensor radio, and the signal was handled on the time axis and demodulated by detecting the frequency, such as in the Arctangent scheme[5]. Therefore, it had some issues such as operating time and power consumption for signal processing to reject noise from the received signal. Panasonic has developed a new demodulation scheme to detect the frequency components directly using Short-time DFT[6]. This technology enables a reduction in circuit size, operating time and power consumption for signal processing.

Notes

[1] Sensor Network: Wireless system for transmitting the environmental data detected by some sensors such as home sensors for temperature, humidity, luminance and power consumption
[2] M2M (Machine to Machine) Sensor Network: The system network to provide autonomously the most suitable service where each devices can communicate without human intervention
[3] IEEE802.15.4x Sensor Network Radio: One of the near field wireless communication standards on IEEE. Though the transmission rate is slower than WLAN and Bluetooth, it is possible to connect with many devices on a network, add or remove the devices without cumbersome settings, and reduce power consumption, making it a suitable wireless standard for M2M sensor networks.
[4] FSK (Frequency-shift keying): A digital modulation scheme
[5] Arctangent scheme: A demodulation scheme for FSK modulation. calculating the differential value of signal arctangent
[6]Short-time DFT (Discrete Fourier Transform): A demodulation scheme with operation of discrete Fourier transform

A test sample of the multi-band wireless transceiver chip

About Panasonic

Panasonic Corporation is a worldwide leader in the development and engineering of electronic technologies and solutions for customers in residential, non-residential, mobility and personal applications. Since its founding in 1918, the company has expanded globally and now operates over 500 consolidated companies worldwide, recording consolidated net sales of 7.85 trillion yen for the year ended March 31, 2012. Committed to pursuing new value through innovation across divisional lines, the company strives to create a better life and a better world for its customers. For more information about Panasonic, please visit the company's website at http://panasonic.net/.

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