Periodic Reporting for period 1 - BROWSE_PLUS (Beam-steered Reconfigurable Optical-Wireless System for Energy-efficient communication – Proving the Concept)
Reporting period: 2018-06-01 to 2019-11-30
Summary of the context and overall objectives of the project
BROWSE+ : Establishing ultra-high capacity wireless communication by means of infrared optical beams
We are getting ever more dependent on the Internet, both in our professional and in our daily life. We want to have access always and everywhere, to our e-mail, social networks, cloud storage, and a plethora of other services. And we do prefer this access by wireless means, as we cherish to move freely and to stay always-connected by means of smartphone, laptop, tablet computer and alike.
Notwithstanding steady progress in radio technologies, e.g. by introducing a range of complex signal processing techniques, radio technologies are getting more and more exhausted in their quest to keep up with the staggering growth of wireless service demands. A hampering wireless access can not only mean slower downloads and on-line games at home, but also faltering security systems such as fire alarms, failing patient monitoring systems in hospitals and elderly-care homes, malfunctioning robots in industry, collisions among autonomic driving cars, etc., and hence many possibly life-threatening risks.
The congestion may be relieved by opening up more spectrum. Moreover, by creating smaller wireless cells the level of spatial multiplexing can be increased. Optical technologies par excellence can address the pressing needs for opening more spectrum and creating smaller cells: the visible light spectrum from 400 to 700 nm implies no less than 320THz (!) of bandwidth, and the infrared spectrum of 1500 to 1600 nm some 12.5 THz, far more than achievable with radio techniques. In addition, optical beamforming, e.g. by means of lenses and mirrors, can yield much smaller cells than attainable with mm-waves.
Optical wireless communication by means of infrared beams
Assume that everybody can get the capacity of an optical fibre, but without being connected to a wire… In the ERC Advanced Grant project BROWSE - Beam-steered Reconfigurable Optical-Wireless System for Energy-efficient communication we have proposed and shown the feasibility of ultra-high capacity data transmission by means of two-dimensionally steerable narrow infrared (IR) beams. Every user can get his personal beam, which he does not need to share. Using optical wavelengths in the IR 1500 to 1600 nm window offers a wide spectrum of no less than 12.5THz; this is the window commonly used in fibre-optical networks in all network layers and for which a plethora of mature high-speed optical devices are readily available. Moreover, IR light beyond 1400 nm is ‘eye-safe’, i.e. IR beams are safe to use as long as their power is less than 10mW. With such power levels a link budget can be realized which enables more than 10Gbit/s per beam. In addition, as Einstein already stated nothing is faster than light in vacuum (and open air), so the latency of light beam links is considerably lower than that of silica fiber links. And as there is no waveguiding mechanism in free space, the light beams also do not suffer from waveguide dispersion, so a beam can fundamentally offer even a higher bandwidth than an optical fibre.
Results
The BROWSE+ project has created a laboratory prototype system in which by means of narrow infrared optical beams data can be delivered at very high speeds per beam to individual user devices. These beams are steered to the devices by passive modules, so-called pencil radiating antennas (PRAs), where the beam’s direction is set by tuning its wavelength. The system has been designed for indoor communication, where the PRAs are mounted on the ceiling of the rooms in the building, and an indoor fibre network is feeding the optical signals to each PRA from a central site.
The BROWSE+ demonstrator system features 2 PRAs which are dynamically fed via a switched fiber network from the central communications controller. The system includes autonomic device localization and real-time user tracking mechanisms in order to steer infrared beams (with at least 10Gbit/s per user) to multiple mobile users individually. Real-time wireless delivery of ultra-high definition video streams to individual devices has been demonstrated. The autonomic network control and management needed to orchestrate the user localization, the dynamic routing of the OWC signals to the two PRAs, and the beam steering has been completed and integrated to the system.
Technical details of the BROWSE+ prototype system
* Prototype configuration:
a demonstrator system with 2 PRAs which are fed via a dynamic single-mode fiber backbone network. Switching between the PRAs enables to circumvent line-of-sight blocking of an IR beam. High-speed (>10 Gbit/s) OWC signals are routed from the central communications controller to the PRAs using a MEMS-based optical cross-connect switch. A PRA can generate up to 128 beams, and data speeds up to 112Gbit/s per beam have been demonstrated over a reach of 2.5 meter covering an area of 1.3x1.3 sqm per PRA.
* User device localization
- using a retro-reflector: utilizing the retro-reflection properties of arrayed miniature corner cubes and monitoring the reflected power when the beam is scanning the area, the localization of user devices can be determined in a self-calibrating way while no active functions at the device are needed. This technique has been validated and integrated in the system. It showed very promising results in terms of localization time and accuracy in the prototype system.
- using a camera: device localization and real-time tracking has been demonstrated using a low-cost optical camera module. The device needs to be equipped with active low-power light-emitting tags, and the beam steering needs to be calibrated to the camera-found positions. This technique enables to steer the IR beams even when the users move continuously, as well as to circumvent line-of-sight (LoS) blocking by hand-over to another PRA.
* Wide field-of-view (FoV) receiver:
in order to avoid the need for delicate beam alignment to the OWC receiver at the user device, a receiver module with a large aperture and wide FoV is needed, while also offering a large bandwidth to enable Gbit/s data speeds. For this, a novel receiver concept using series/parallel arrangement of photodiodes has been designed and filed for patent. A series/parallel arrangement of 16 photodiode elements (in a quad arrangement, and ~1 GHz bandwidth each) has been implemented, providing a bandwidth of 1.0GHz and an aperture diameter of 1.3mm at a fill factor of about 30%.
* Autonomic system control and management:
autonomous operation of the entire network including beam steering, device localization, and data transmission/reception control at a centralized site has been developed using LABVIEW as the main control programme running on a laptop controller.
Dissemination, PR activities
The project has generated 24 scientific publications in the major journals and conferences in the domain of optical communication. Moreover, the results were also presented to the general audience in popular technical magazines, on websites, in newspapers, and in TV and radio broadcast programmes. Live demonstrations of the system setup were given to many visitors, among which the Dutch Minister of Science and Education Mrs. Van Engelshoven, and many high-level industrial decision makers.
Four US patent applications were filed.
BROWSE+ was selected by the Board of the university as the candidate from Eindhoven University of Technology in the national Huibregtsen prize competition for the most innovative project in 2018, and out of 42 submissions it was among the 6 remaining finalists (but did not win).
Follow-up
BROWSE’s technology has attracted interest of vested industries, and triggered several new follow-up initiatives together with them. It is seen as the next step leading to high data rate optical wireless communication after VLC (visible light communication) which is emulating data communication onto LED illumination systems and only has limited data rates not extending significantly beyond WiFi. Optical wireless communication in general needs line-of-sight. The BROWSE technology is therefore not intending to fully replace radio-based wireless communication (such as WiFi), but to off-load high-data rate services from radio-based networks which thus get the necessary ample room to host the numerous internet-of-things devices.
The project has led to follow-up R&D cooperation activities with the Dutch network operator KPN, and Signify (formerly Philips Lighting).
Market prospects have been identified. Opportunities to establish a start-up are under investigation.
We are getting ever more dependent on the Internet, both in our professional and in our daily life. We want to have access always and everywhere, to our e-mail, social networks, cloud storage, and a plethora of other services. And we do prefer this access by wireless means, as we cherish to move freely and to stay always-connected by means of smartphone, laptop, tablet computer and alike.
Notwithstanding steady progress in radio technologies, e.g. by introducing a range of complex signal processing techniques, radio technologies are getting more and more exhausted in their quest to keep up with the staggering growth of wireless service demands. A hampering wireless access can not only mean slower downloads and on-line games at home, but also faltering security systems such as fire alarms, failing patient monitoring systems in hospitals and elderly-care homes, malfunctioning robots in industry, collisions among autonomic driving cars, etc., and hence many possibly life-threatening risks.
The congestion may be relieved by opening up more spectrum. Moreover, by creating smaller wireless cells the level of spatial multiplexing can be increased. Optical technologies par excellence can address the pressing needs for opening more spectrum and creating smaller cells: the visible light spectrum from 400 to 700 nm implies no less than 320THz (!) of bandwidth, and the infrared spectrum of 1500 to 1600 nm some 12.5 THz, far more than achievable with radio techniques. In addition, optical beamforming, e.g. by means of lenses and mirrors, can yield much smaller cells than attainable with mm-waves.
Optical wireless communication by means of infrared beams
Assume that everybody can get the capacity of an optical fibre, but without being connected to a wire… In the ERC Advanced Grant project BROWSE - Beam-steered Reconfigurable Optical-Wireless System for Energy-efficient communication we have proposed and shown the feasibility of ultra-high capacity data transmission by means of two-dimensionally steerable narrow infrared (IR) beams. Every user can get his personal beam, which he does not need to share. Using optical wavelengths in the IR 1500 to 1600 nm window offers a wide spectrum of no less than 12.5THz; this is the window commonly used in fibre-optical networks in all network layers and for which a plethora of mature high-speed optical devices are readily available. Moreover, IR light beyond 1400 nm is ‘eye-safe’, i.e. IR beams are safe to use as long as their power is less than 10mW. With such power levels a link budget can be realized which enables more than 10Gbit/s per beam. In addition, as Einstein already stated nothing is faster than light in vacuum (and open air), so the latency of light beam links is considerably lower than that of silica fiber links. And as there is no waveguiding mechanism in free space, the light beams also do not suffer from waveguide dispersion, so a beam can fundamentally offer even a higher bandwidth than an optical fibre.
Results
The BROWSE+ project has created a laboratory prototype system in which by means of narrow infrared optical beams data can be delivered at very high speeds per beam to individual user devices. These beams are steered to the devices by passive modules, so-called pencil radiating antennas (PRAs), where the beam’s direction is set by tuning its wavelength. The system has been designed for indoor communication, where the PRAs are mounted on the ceiling of the rooms in the building, and an indoor fibre network is feeding the optical signals to each PRA from a central site.
The BROWSE+ demonstrator system features 2 PRAs which are dynamically fed via a switched fiber network from the central communications controller. The system includes autonomic device localization and real-time user tracking mechanisms in order to steer infrared beams (with at least 10Gbit/s per user) to multiple mobile users individually. Real-time wireless delivery of ultra-high definition video streams to individual devices has been demonstrated. The autonomic network control and management needed to orchestrate the user localization, the dynamic routing of the OWC signals to the two PRAs, and the beam steering has been completed and integrated to the system.
Technical details of the BROWSE+ prototype system
* Prototype configuration:
a demonstrator system with 2 PRAs which are fed via a dynamic single-mode fiber backbone network. Switching between the PRAs enables to circumvent line-of-sight blocking of an IR beam. High-speed (>10 Gbit/s) OWC signals are routed from the central communications controller to the PRAs using a MEMS-based optical cross-connect switch. A PRA can generate up to 128 beams, and data speeds up to 112Gbit/s per beam have been demonstrated over a reach of 2.5 meter covering an area of 1.3x1.3 sqm per PRA.
* User device localization
- using a retro-reflector: utilizing the retro-reflection properties of arrayed miniature corner cubes and monitoring the reflected power when the beam is scanning the area, the localization of user devices can be determined in a self-calibrating way while no active functions at the device are needed. This technique has been validated and integrated in the system. It showed very promising results in terms of localization time and accuracy in the prototype system.
- using a camera: device localization and real-time tracking has been demonstrated using a low-cost optical camera module. The device needs to be equipped with active low-power light-emitting tags, and the beam steering needs to be calibrated to the camera-found positions. This technique enables to steer the IR beams even when the users move continuously, as well as to circumvent line-of-sight (LoS) blocking by hand-over to another PRA.
* Wide field-of-view (FoV) receiver:
in order to avoid the need for delicate beam alignment to the OWC receiver at the user device, a receiver module with a large aperture and wide FoV is needed, while also offering a large bandwidth to enable Gbit/s data speeds. For this, a novel receiver concept using series/parallel arrangement of photodiodes has been designed and filed for patent. A series/parallel arrangement of 16 photodiode elements (in a quad arrangement, and ~1 GHz bandwidth each) has been implemented, providing a bandwidth of 1.0GHz and an aperture diameter of 1.3mm at a fill factor of about 30%.
* Autonomic system control and management:
autonomous operation of the entire network including beam steering, device localization, and data transmission/reception control at a centralized site has been developed using LABVIEW as the main control programme running on a laptop controller.
Dissemination, PR activities
The project has generated 24 scientific publications in the major journals and conferences in the domain of optical communication. Moreover, the results were also presented to the general audience in popular technical magazines, on websites, in newspapers, and in TV and radio broadcast programmes. Live demonstrations of the system setup were given to many visitors, among which the Dutch Minister of Science and Education Mrs. Van Engelshoven, and many high-level industrial decision makers.
Four US patent applications were filed.
BROWSE+ was selected by the Board of the university as the candidate from Eindhoven University of Technology in the national Huibregtsen prize competition for the most innovative project in 2018, and out of 42 submissions it was among the 6 remaining finalists (but did not win).
Follow-up
BROWSE’s technology has attracted interest of vested industries, and triggered several new follow-up initiatives together with them. It is seen as the next step leading to high data rate optical wireless communication after VLC (visible light communication) which is emulating data communication onto LED illumination systems and only has limited data rates not extending significantly beyond WiFi. Optical wireless communication in general needs line-of-sight. The BROWSE technology is therefore not intending to fully replace radio-based wireless communication (such as WiFi), but to off-load high-data rate services from radio-based networks which thus get the necessary ample room to host the numerous internet-of-things devices.
The project has led to follow-up R&D cooperation activities with the Dutch network operator KPN, and Signify (formerly Philips Lighting).
Market prospects have been identified. Opportunities to establish a start-up are under investigation.