Millimeter-waveband wireless device implemented in CMOS circuit

With these developments, they succeeded in achieving wireless transmission speeds of 56Gbps, the world's fastest. In recent years, to cope with the large increase in data traffic resulting from the widespread use of smartphones and other devices, networks that link base stations use optical fiber. One issue with this approach, however, is that it is difficult to expand service in areas where it is difficult to install a network of optical fiber cables, such as in urban areas or areas surrounded by rivers or mountains.

To deal with this issue, Tokyo Institute of Technology and Fujitsu Laboratories have now developed high-speed wireless transceiver technologies that use the millimeter-waveband (30-300GHz), where there are few competing wireless applications and which are capable of large-capacity communications. This technology makes it possible to have high-capacity wireless communications equipment that can be installed outdoors in applications where fiber-optic networks would be difficult to lay.

The details of this technology will be announced at the IEEE International Solid-State Circuits Conference 2016 (ISSCC 2016), the largest conference related to semiconductor technology, opening in San Francisco on January 31^st (ISSCC Presentation Number 13.3).

With sharp increases in data communications traffic resulting from the proliferation of smartphones, the expansion in the capacity of backbone networks - which connect wireless base stations to core networks, and base stations to each other - is accelerating. In the past, macro-cell base stations were mainly used, each of which can cover an area with several kilometers of range, but in recent years these have been supplemented with large quantities of small-cell base stations, each of which has a range of only a few hundred meters, to accommodate the increase in communications traffic.

Also, fiber-optic lines, which can transmit large volumes of data, are currently the most common way to handle communications between base stations. But laying new fiber-optic cables can be difficult in tightly packed urban areas, or in places hemmed in by mountains or rivers, so it has been hoped that high-capacity wireless equipment could be created that can easily be installed outdoors.

High-capacity wireless transmissions need to use broad frequency ranges. This makes the use of the millimeter-waveband a suitable option, as few competing wireless applications use it. But because the millimeter-waveband uses such high frequencies, designing CMOS integrated circuits for that purpose has been a challenge, as the circuits need to be designed to operate near their limits. It has also been difficult to develop low-loss transceiver circuits that modulate and demodulate broadband signals into and out of the millimeter-waveband with high quality and low-loss interface circuits, which connect the circuit board to the antenna.