Researchers at Oxford University has reignited interest in optical wireless networking, demonstrating a system capable of transmitting at rates of 224Gb/s with a field-of-view offering whole-room coverage.
Optical wireless networking isn't a new concept: back in 2008 a team of researchers at Boston University announced a project to modulate LED lights to transmit data to client devices
. Where the Boston system was limited to speeds of 10Mb/s, however, the research published by photonics engineer Dominic O'Brien and his team has somewhat of a higher limit: 224GB/s over six channels. The system also offers a range of three metres and a field-of-view which gives it whole-room coverage, although the wider the field of view the slower the data transfer rate - dropping to 112Gb/s at a 36 degree FoV.
O'Brien believes that the technology could augment, rather than replace, Wi-Fi. 'The world of communications is a world where everybody always wants more bandwidth,
' he told IEEE Spectrum
of his research. Where Wi-Fi is relatively slow, its radiofrequency signals penetrate solid objects - including furniture, walls and even people - while the faster optical system requires line-of-sight. The use of visible and near-visible light, however, does not require a chunk of radiofrequency spectrum - and O'Brien's system neatly dodges the problem of using visible-light optical networking as proposed by Boston by making use of invisible infrared light, meaning it works even if you'd prefer to use your PC in the dark.
The biggest drawback to the Oxford system at present is that the receiver and transmitter must be in known locations, making it unsuitable for use in mobile devices like smartphones, tablets and laptops - exactly the devices which would benefit from a faster wireless network. O'Brien's team is reportedly working on this problem, building a tracking system which would allow the transmitter to locate a receiver device within a room without prior knowledge of its location.
The team's paper, Beyond 100-Bg/s Indoor Wide Field-of-View Optical Wireless Communications
, is published in the latest Photonics Technology Letters
journal, which describes the system as 'the first demonstration of a wireless link of this time with a FoV which offers practical room-scale coverage