NEC says it has developed a radio-over-fibre system with a 1-bit fibre transmission, which enables ‘the realisation of a compact distributed antenna unit at low cost.’

The technology allows high-frequency analogue signals to be transmitted using an ‘inexpensive electrical-to-optical converter for general-purpose digital communications’, which NEC says makes it possible to ‘affordably build stable millimeter-wave communication networks for Beyond 5G/6G.’

The 1-bit fibre transmission method converts high-frequency analogue signals into 1-bit pulse signals that are transmitted over fibre, we’re told, and the desired analogue signal can then be reproduced through a filter.

Designed with high-rise buildings, underground malls, factories, railways, indoor facilities, and other obstacle-laden environments in mind, the idea is the 1-bit fibre transmission method allows for an mmWave antenna with low power consumption and cost reduction. “It will therefore promote the uptake of high-speed and large-capacity communications using millimeter waves for Beyond 5G/6G,” claims the release.

NEC says that since around 80% of mobile communication traffic occurs indoors, mmWave is being considered as an indoor solution. The release states:

“However, since there is significant propagation loss and high linearity in the millimeter-wave frequency band, it is imperative to ensure line of sight between base stations and terminals to achieve sufficient quality of service (QoS). While dense installation of distributed antenna units (DA) for direct transmission and reception of data with terminals and avoiding obstacles is known to be effective in resolving these issues, the size, power consumption, and cost of installing the required number of DA have proven to be major issues. To overcome these issues, NEC developed a radio-over-fiber system (RoF) and a related transmission method.”

All in all, the system is supposed to make it possible to install ‘compact, low-cost Das’ in high density, which NEC says is expected to improve the mmWave communication environment by ensuring the line of sight between DAs and terminals.

mmWave deployments have been touted as a new revenue stream for telcos –  last week Deutsche Telekom said it had successfully trialled 5G frequencies in the mmWave range at 26 GH) for the first time in industrial scenarios.

For the technically minded, here are some diagrams NEC provided to illustrate its new system:

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