A new technique that requires only one channel for two-way communication and could enable global roaming on 4G has been devised by UK researchers.
Radio systems like mobile phones and wireless internet connections use as much of the radio spectrum as is necessary. But the new technology can estimate and cancel out the interference from one’s own transmission, allowing a radio device to transmit and receive on the same channel at the same time. The scientists from the University of Bristol said their technology could use half as much spectrum compared to the current technology.
But this research in particular, as well as being part of the evolution of 5G mobile, is also relevant to 3G and 4G in mobile devices. Traditionally, a separate filtering component is required for each frequency band, which means that mobile phones can’t support all the frequency channels available around the world.
Different devices are manufactured for different regions of the world and there are currently no 4G phones capable of unrestricted global roaming. However, by replacing these filters with the research team’s duplexer circuit it would create smaller and cheaper devices that could allow manufacturers to produce a single model for the entire world. This would enable global roaming on 4G and would further decrease cost through greater economies of scale.
The team of five designed and built a full-duplex transceiver architecture, which combines electrical balance isolation and active radio frequency cancellation. Their prototype can suppress interference by a factor of over 100 million and uses low-cost, small form factor technologies, making it well suited to use in mobile devices such as smartphones and tablets.
Leo Laughlin, a PhD student from the University’s EPSRC Centre for Doctoral Training (CDT) in Communications, said:
“Until now there has been a fundamental unsolved problem with radio communication. Since the radio spectrum is a limited resource and with network operators paying billions of pounds to access the spectrum, solving this problem would bring us one step closer to the faster, cheaper and greener devices of our connected future.”
Source: Engineering and Technology Magazine, GSMA (Diagram)