5G wireless networks
Japanese researchers have succeeded in building a 100Gbps wireless network using a new terahertz radio transmitteriStock

Japanese researchers have succeeded in developing a super-fast 100Gbps wireless internet network to rival fibre optic broadband speeds by using terahertz radio transmitters. Researchers from Hiroshima University, Panasonic and Japan's National Institute of Information and Communications Technology have developed a radio transmitter operating in the submillimetre terahertz frequency range that is able to carry high speed data connections over multiple channels.

At the moment, scientists all over the world are experimenting to create super-fast 5G wireless transmission speeds, but they are predominantly using millimetre wave frequencies between 6GHz to 100GHz.

To give you some context, today most home Wi-Fi networks transmit data over the 2.4GHz and 5GHz frequency bands, while high-speed LAN connections use 60GHz to deliver speeds of 4.6Gbps, but this is only over a short distance.

And if you look at mobile broadband today, EE's 4G network in the UK, which is the biggest in Europe, offers only 300Mbps maximum data speeds over the 800MHz and 1800MHz bands.

Developing terahertz transmitters

Instead, the Japanese researchers' idea is to send transmissions over the 275-305GHz frequency range, which is much higher than millimetre wave. The terahertz radio transmitter operates at 300GHz+ and is able to transmit signals of 10Gbps per data channel over multiple channels in the frequency range, which has never been seen before.

"Today, we usually talk about wireless data-rates in megabits per second or gigabits per second. But I foresee we'll soon be talking about terabits per second. That's what THz wireless technology offers. Such extreme speeds are currently confined in optical fibres. I want to bring fibre optic speeds out into the air, and we have taken an important step towards that goal," said Professor Minoru Fujishima, Department of Semiconductor Electronics and Integration Science at Hiroshima University.

"We plan to develop receiver circuits for the 300GHz band, as well as modulation and demodulation circuits that are suitable for ultra high-speed communications."

5G standards have yet to be defined

Unfortunately, there are still a multitude of problems that need to be solved before it is possible to operate wireless networks in the terahertz frequency band, and there are no details from the researchers about exactly how great or small a distance was used to achieve the 100Gbps speed.

Industry bodies, such as the Institute of Electrical and Electronics Engineers (IEEE) and the GSM Association (GSMA), are yet to define any standards for 5G, a term used to describe next-generation mobile networks that are expected to have incredibly fast speeds.

In October 2014, Samsung Electronics set the first record by achieving a wireless speed of 7.5Gbps in tests at its DMC R&D Centre at Samsung Electronics in Suwon, South Korea. But in November 2014, the record was beaten by the University of Surrey's 5G Innovation Centre (5GIC), which was founded by a host of telecoms industry partners, including Huawei, Fujitsu, EE, Aircom, BT, Samsung, Telefonica, Vodafone, Aeroflex and Rohde & Schwarz, as well as the BBC.

5GIC achieved a speed of 0.8 terabits (800Gbps) in its tests. Then on 25 February 2015, it beat its own record by hitting 1Tbps, which is currently the world record.

Speed is nice, but distance counts too

When it comes to judging 5G wireless speeds, distance and frequency spectrum of the network is also important. So while 5GIC may have hit the fastest speed, their tests were conducted in a laboratory over a distance of only 100m and it is not known what kind of network was used, compared to the Samsung test, which was over a 4.35km outdoor race track and using a 28GHz network.

On 3 February Fujitsu and the Tokyo Institute of Technology announced that they were able to achieve 56Gbps using a new Complementary Metal-Oxide Semiconductor (CMOS) wireless transceiver chip, but the speed was achieved over a distance of only 10cm.

So far, the most impressive test has been that of Huawei and NTTDoComo, who achieved mobile internet speeds of 3.6Gbps outdoors across the city of Chengdu in Sichuan Province, China in October 2015 on a sub-6GHz frequency band.