NL2032214B1 - Bi-directional all-optical wireless communication system with autonomous optical beam steering. - Google Patents
Bi-directional all-optical wireless communication system with autonomous optical beam steering. Download PDFInfo
- Publication number
- NL2032214B1 NL2032214B1 NL2032214A NL2032214A NL2032214B1 NL 2032214 B1 NL2032214 B1 NL 2032214B1 NL 2032214 A NL2032214 A NL 2032214A NL 2032214 A NL2032214 A NL 2032214A NL 2032214 B1 NL2032214 B1 NL 2032214B1
- Authority
- NL
- Netherlands
- Prior art keywords
- owc
- transmitter
- receiver
- optical beam
- optical
- Prior art date
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 146
- 238000004891 communication Methods 0.000 title claims abstract description 32
- 230000005540 biological transmission Effects 0.000 claims description 11
- 239000000835 fiber Substances 0.000 claims description 11
- 230000005484 gravity Effects 0.000 claims description 9
- 239000011888 foil Substances 0.000 claims description 8
- 238000011144 upstream manufacturing Methods 0.000 description 20
- 230000002457 bidirectional effect Effects 0.000 description 13
- 230000004075 alteration Effects 0.000 description 4
- 230000004807 localization Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 241000375392 Tana Species 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 108010023321 Factor VII Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- ZFTOZMXTUSRLTC-ZMHPAJMFSA-N desulfoglucoberteroin Natural products CSCCCCCC(=N)S[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O ZFTOZMXTUSRLTC-ZMHPAJMFSA-N 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000003032 molecular docking Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/1143—Bidirectional transmission
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/1149—Arrangements for indoor wireless networking of information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Computing Systems (AREA)
- Optical Communication System (AREA)
Abstract
An Optical Wireless Communication, OWC, receiver is presented for receiving from an OWC transmitter, an incoming optical beam modulated with data and outputting an electrical output signal comprising the modulated data, wherein the optical beam is a narrow steered optical beam, the receiver comprising: a lens arranged to receive the incoming optical beam from the OWC transmitter; a receiver unit arranged to receive the incoming optical beam through the lens and generate the electrical output signal from the data modulated on the incoming optical beam; an alignment unit arranged to provide aligning means to the OWC transmitter for control of steering the optical beam to align with the OWC receiver, wherein the alignment unit is arranged coaxially around the optical entry aperture of the receiver unit and is comprised of a retroreflective layer.
Description
Title: Bi-directional all-optical wireless communication system with autonomous optical beam steering.
The present invention relates generally to optical wireless communications, and more in particular to a bi-directional all-optical wireless communication system with optical beam steering and alignment thereof which is done autonomously by the system.
Although use and innovation of Radio Frequency, RF, based wireless communication is making steady progress, its popularity is also leading to congestion of the radio spectrum due to the fast rising capacity demands. Optical Wireless
Communication, OWC, is a form of optical communication in which unguided visible, infrared (IR), or ultraviolet (UV) light is used to carry a signal. OWC is quickly gaining interest in industry since the spectrum of (visible) light (with a wavelength range of about 400-700 nm) offers no less than 320 THz of bandwidth, and the spectrum commonly used in long-reach fibre optical communication (1500-1600 nm) about 12.5
THz, both much larger than even the upcoming THz radio technologies can offer.
Moreover, OWC is not affected by electromagnetic interference (EMI) disturbances, while radio wireless communication can be affected by EMI.
OWC can be used, among others, in a wide range of applications including wireless local area networks, wireless personal area networks and vehicular networks. The OWC systems that operate in the visible band are commonly referred to as Visible Light Communication, VLC, systems. The communicated data is modulated by pulsing the visible light at high speeds without noticeable effect on the lighting output and the human eye. VLC systems can be piggy-backed on LED illumination systems, as the LED's output light may not only serve illumination purposes but the LED may also be modulated with data, although with limited bandwidth as the LED in an illumination system is basically not designed for that.
The OWC systems that operate by beams in the Infra-Red, IR, and near-IR band offer protocol-transparent links with high data rates each. Such OWC systems use infrared beams which each can be directed on-demand to user devices.
In this way, individual wireless links can be established to those devices with very high congestion-free capacity and high privacy as these beams are not shared and cannot be accessed by users which are not within the beam’s footprint.
OWC systems have a lot of advantages over RF based communication systems. As indicated, OWC systems have huge bandwidth potential, but moreover, the optical spectrum is unregulated and unlicensed. Since light cannot penetrate walls, OWC systems provide enhanced privacy and security.
Besides these advantages, OWC systems also have several technical challenges, such as the challenge to efficiently steer the optical narrow beams individually and the challenge of how to align the optical beam between the transmitter and receiver without the need of complex alignment measures, as these complicate the user's device and thus lead to increased costs. Next to that, it also is a challenge to avoid the need of a pre-existing feedback path from the receiver to the transmitter which should monitor the alignment process. Such pre-existing feedback path typically is not available when initialising the OWC system.
As such, most known OWC systems focus on downstream connectivity only. Bidirectional beam-steered systems reported mostly employed hybrid links (optical beam down, mm-wave radio up). Hybrid links, however, do not preserve the key advantages of all-optical OWC, such as security against eaves- dropping and EMI immunity. Alternatively, known all-optical bidirectional systems simply duplicated the downstream link into an upstream one, e.g. using MEMS (Microelectromechanical systems) mirrors, or SLMs (spatial light modulators), or cover very short distances such as for docking systems. It should be noted that in an indoor network, however, the downstream OWC links are typically emerging from a common point-to-multipoint (P2MP)} multicasting unit mounted at the room’s ceiling, whereas the upstream links are MP2P links from each user device to the ceiling’s upstream receiver. Such asymmetry is not optimally served by duplicating the downstream link into an upstream one.
Accordingly, it is an object of the present disclosure, to provide an all-optical bidirectional OWC system, which allows a beam-steered OWC upstream link for each user without the complex alignment measures in the user's device and without the need of a pre-existing feedback path from receiver to transmitter.
In a first aspect, there is provided an Optical Wireless
Communication, OWC, receiver for receiving from an OWC transmitter, an incoming optical beam modulated with data and outputting an electrical output signal comprising the modulated data, wherein the optical beam is a narrow steered optical beam, the receiver comprising: - a lens arranged to receive the incoming optical beam from the OWC transmitter; - a receiver unit arranged to receive the incoming optical beam through the lens and generate the electrical output signal from the data modulated on the incoming optical beam; - an alignment unit arranged to provide aligning means to the OWC transmitter for control of steering the optical beam to align with the OWC receiver, wherein the alignment unit is arranged coaxially around the optical entry aperture of the receiver unit and is comprised of a retroreflective layer.
In a second aspect, there is provided an Optical Wireless
Communication, OWC, transmitter for transmitting to an OWC receiver, an outgoing optical beam modulated with data from a received electrical input signal, wherein the optical beam is a narrow steered optical beam, the transmitter comprising: - a lens arranged to transmit the outgoing optical beam;
- a transmitter unit arranged to modulate the data from the received electrical input signal onto the outgoing optical beam and arranged to transmit the outgoing optical beam through the lens; - a beam steering unit, arranged to control a position of the transmitter unit in respect of the lens in at least two dimensions, for steering the optical beam to align with the OWC receiver, and wherein the beam steering unit is arranged to operate in a scanning mode and an transmission mode, wherein the beam steering unit during the scanning mode controls the position of an output fiber of the transmitter unit to exit the lens in a sequence of scanning steps, wherein the optical beam is steered in accordance with a two-dimensional array by displacing the transmitter unit laterally over the two dimensions relative to the lens, and where an optical power monitoring unit close to the exit lens of the transmitter is used to determine reflected optical beam power values reflected from the receiver for each of the scanning steps; and wherein the OWC transmitter is further arranged to determine a center of gravity from the reflected optical beam power values to control the steering of the optical beam to align with the OWC receiver in accordance with the detected center of gravity during the transmission mode.
Optical Wireless Communication, OWC, systems typically comprise a central unit, e.g. a device which is mounted on the ceiling and is arranged to communicate with multiple user devices. Both the ceiling central unit and the user device comprise a receiver and a transmitter, i.e. the ceiling central unit has a upstream receiver, US Rx, to receive upstream optical beams from the upstream transmitters US Tx of each user device, and each user device has a downstream receiver, DS Rx to receive downstream optical beams from the downstream transmitter, DS Tx in the ceiling central unit.
For optical wireless communication from one site (site A) to another site (site B}, e.g. from the user device at site A to the ceiling central unit at site B, in the known systems using beam steering, the transmitter at A needs to get feedback from the receiver at B to learn whether the data connection has been established adequately. But such feedback requires a transmission path from the receiver at B back to the transmitter at A, which requires that such return path from B to A has already been established beforehand.
In bidirectional optical wireless high-speed data transmission, narrow optical beams have to be used for the path from the transmitter at A to the receiver at
B, as well as for the return path from the transmitter at B to the receiver at A. Hence 5 beam pointing is needed in both directions. Doing the beam pointing from A to B with the aid of such a return path thus requires that the beam pointing from B to A has already been solved: this represents a bootstrap problem. Examples of bidirectional optical wireless high-speed data transmission have been reported before using identical beam steering techniques at both sites A and B: e.g., using MEMS micro- mirrors, and using SLMs.
To avoid this bootstrap problem, the transmitter needs to be able to set up the connection to the receiver autonomously, without needing a pre-existing return link from the receiver to the transmitter.
Examples of bidirectional optical wireless systems using steering of optical beams for high-speed data transmission based on MEMS micromirrors and
SLMs use maximalisation of the received optical power at site B to optimize the beam pointing from site A; for this, the received power values at B need to be reported to A by means of an existing return path.
By using a foil of miniature passive retro-reflectors an optical device localization technique is provided for aiding the beam steering from A to B by using a foil of miniature passive retro-reflectors in B. The foil of retro-reflectors (e.g. corner cubes) is positioned close to the optical entry of B, and reflects the incoming beam into the same direction as it came from. Due to such retro-reflective layer, a pre- existing return path from B to A is not required. The power of the reflected beam is monitored with a photodetector positioned close to the exit aperture of A, and thus the alignment of the beam relative to B is monitored.
The inventor had the insight of providing a layer of retroreflective layers, or retroflectors which are disposed coaxially around the receiver unit (B), more preferably, around the entry aperture of the receiver unit, this coaxial layer is preferably a ring-shaped coaxial layer having a surface of, and preferably comprised of a foil of miniature retro-reflectors (‘RR ring’). The retroreflective layer reflects incoming beams exactly into the same direction where they came from. It does not require any pre-existing return path, nor any action at the site B (ceiling central unit site).
At the transmitter, the beam power reflected from the RR ring is monitored which enables automatically aligning the optical (upstream) beam to the US receiver, employing a dedicated RR hole seeking algorithm, which determines or more precisely, calculates the centre of the RR which corresponds to the aperture of the US receiver unit such that the US beam can be steered exactly into the US receiver aperture.
The algorithm, also referred to as a Center-of-Gravity, CoG algorithm, yields the center of the ring, hence the center of the receiver aperture at site B (US
Rx) with high accuracy. The algorithm calculates the center from the measured data which were gathered during the 2D scanning process shown of the transmitter.
Alternatively, a Center-of-Mass algorithm may be used, although the center-of-mass may be similar to the center-of-gravity when the object is in a uniform gravitational field as in present case.
In an example of the first aspect, the alignment unit comprises a ring- shaped retroreflective layer arranged coaxially around the optical entry aperture of the receiver unit.
Preferably, the retroreflective layer is ring shaped, as the ring-shaped layer eases and increases the accuracy of the beam-steering direction determined from the center-of-gravity algorithm.
In an example of the first aspect, the retroreflective layer comprises a retroreflective foil.
Preferably, the retroreflective layer is a retroreflective foil, for being commercially available at low costs (as used amongst others for road signage).
In an example of the first aspect, the retroreflective layer comprises a plurality of miniature corner cubes distributed over the surface and arranged coaxially around the optical entry aperture the receiver unit.
Preferably, the retroreflective layer is continuous over the whole surface of the layer, e.g. ring, but in an example, it may contain segments of retroreflective material, or miniature corner cubes distributed evenly over the layer.
In an example of the second aspect, the optical beam has a shape corresponding to the shape of the receiver unit and an inner region of the retroreflective layer arranged coaxially around the optical entry aperture of the receiver unit of the OWC receiver.
The shape and/or size of the beam preferably correspond to the aperture of the US receiver unit, e.g. the beam is preferably circular shaped to correspond with the inner region of the ring-shaped retroreflective layer around the aperture of the US receiver unit.
In an example of the second aspect, the beam steering unit comprises stepper motors for step-wise control of the position of the transmitter unit in at least two dimensions.
In an example of the second aspect, the transmitter unit is arranged to control the beam spot diameter in accordance with an aperture of the receiver unit of the OWC receiver.
In an example of the second aspect, the beam steering unit is arranged to configure a scanning step size of the scanning sequence during the scanning mode.
In an example of the second aspect, the transmitter unit is arranged to increase the beam spot diameter during the scanning mode in respect of the beam spot diameter during the transmission mode.
The beam spot diameter may be controlled or configured e.g. to have a different beam spot diameter during the scanning mode than during the transmission mode. Moreover, the scanning mode may comprise multiple scanning steps, e.g. a first coarse scanning sequence with larger scanning step sizes and/or different beam spot diameter, for rough localization of the OWC receiver, and a second fine scanning sequence for accurate aperture localisation. The effect of introducing both a coarse and fine scanning sequence is that it allows faster localization of the OWC receiver as compared to scanning a large area with a narrow beam spot diameter used in a single or fine scanning sequence. Once the OWC receiver is located, the fine scanning sequence can be initiated to localize the optical entry aperture of the receiver.
In an example of the second aspect, the lens unit comprises a planoconvex lens.
In an example of the second aspect, the lens unit comprises a doublet lens.
In an example of the second aspect, the lens unit comprises a triplet lens.
The lens unit may comprise a low cost planoconvex lens or doublet lens, but more preferably a triplet lens which gives lower aberrations and thus minimal changes of the spot’s shape when scanning, which improves the accuracy of the CoG algorithm.
In an example of the second aspect, the OWC transmitter further comprises one, two, three or more photodiodes for detecting the optical beam power from the optical beam reflected by the retroreflective layer of the OWC receiver.
In a third aspect, there is provided, an Optical Wireless
Communication, OWC, system, comprising an OWC transmitter, and an OWC receiver, wherein the OWC receiver is arranged for receiving from the OWC transmitter, an incoming optical beam modulated with data and outputting an electrical output signal comprising the modulated data, wherein the optical beam is a narrow beam steering optical beam, the receiver comprising: - a lens arranged to receive the incoming optical beam from the OWC transmitter;
- a receiver unit arranged to receive the incoming optical beam through the lens and generate the electrical output signal from the data modulated on the incoming optical beam;
- an alignment unit arranged to provide aligning means to the OWC transmitter for control of steering the optical beam to point towards the OWC receiver,
wherein the alignment unit is arranged coaxially around the optical entry aperture of the receiver unit and comprised of a retroreflective layer;
wherein the OWC transmitter is arranged for transmitting to the OWC receiver, an outgoing optical beam modulated with data from a received electrical input signal, wherein the optical beam is a narrow steered optical beam, the transmitter comprising:
- a lens arranged to transmit the outgoing optical beam;
- a unit arranged to modulate the data from the received electrical input signal onto the outgoing optical beam and arranged to transmit the outgoing optical beam through the lens;
- a beam steering unit, arranged to control a position of the transmitter unit in respect of the lens in at least two dimensions, for steering the optical beam to align with the OWC receiver, and wherein the beam steering unit is arranged to operate in a scanning mode and an transmission mode, wherein the beam steering unit during the scanning mode controls the position of an output fiber of the transmitter unit to exit the lens in a sequence of scanning steps, wherein the optical beam is steered in accordance with a two-dimensional array by displacing the transmitter unit laterally over the two dimensions relative to the lens to determine reflected optical beam power values for each of the scanning steps; and wherein the OWC transmitter is further arranged to determine a center of gravity from the reflected optical beam power values to control the steering of the optical beam to align with the OWC receiver in accordance with the detected center of gravity during the operational mode.
The skilled person will appreciate that all examples and advantages of the first aspect of the present disclosure are equally applicable for the second aspect of the present disclosure.
Fig. 1: shows a bidirectional OWC system with automatic upstream beam self-alignment;
Fig. 2: shows a design of the upstream optical path
Fig. 3: shows an upstream beam coupling to US receiver ((US beam
Spot diameter Dbeam2=15mm, focal length of lens 1 f1=20mm, focal length of lens 2 f2=5mm, diameter of photodiode DPD=1.32mm);
Fig. 4: shows a 2D angular steering of US beam;
Fig. 5: shows an US beam spot at the RR ring (by tracing the rays emitted from lens 1, with 1027 Gaussian beams from US Tx; red circle: 315mm);
Fig. 6: shows scanning the RR ring at the US Rx
Fig. 7: shows monitoring the reflected beam power from the RR, for Dbeam2=15mm, RR inner diameter D1=25mm, outer diameter D2=62mm (left: analytical results; right: experimental results);
Fig. 8: shows a bidirectional OWC lab system (blue: fiber lines; red: copper lines).
Fig. 1 shows the architecture of the all-optical bidirectional OWC system 101. The ceiling central unit 110 hosts the passive pencil-radiating antenna (PRA) unit 102 which directs narrow downstream (DS) optical beams in 2 dimensions according to their wavelength 103, 104; the DS data are fed from A-tunable laser transmitters. Thus, each user device 105a, 105b is DS-connected by his private i- beam (31, A2, …).
For upstream, US, a beam with arbitrary wavelength (A0) 106 is preferred, in order to avoid costly A-tunable sources and their control circuitry.
Therefore, the upstream beam steering 107 in 2 dimensions from the upstream transmitter (US Tx) 107 towards the upstream receiver (US Rx) 108 through the lens 111 at the ceiling central unit 110 is done by mechanical means. This typically requires an optical feedback loop from the ceiling unit to each user to aid the pointing of the upstream beam and establishing the upstream path; it requires to set up the DS path first. To circumvent this bootstrapping issue, a ring 109 of retro-reflecting miniature corner cubes (RR ring) is proposed which surrounds the aperture of the upstream receiver (US Rx) 108. Such RR ring 109 can be cut from commercially available RR foils commonly used for e.g. road signage. At the user 105a, 105b, the US power reflected from the RR ring 109 is monitored and enables automatically aligning the US beam 106 to the US receiver 108, employing a dedicated RR hole-seeking algorithm.
Multiple users 105a, 105b can deploy the RR ring 109 simultaneously for their US beam alignment, as the RR ring 109 reflects an US beam 106 to its originating user only. The US receiver 108 at the ceiling will receive US beams 106 from multiple users 105a, 105b, so an US medium access control protocol is needed, e.g., a TDMA protocol similar to the ones in commercial TDMA PON systems.
Fig. 2 shows the design of the US optical path, starting at the user site and covering a distance d ending at the PRA site at the ceiling. Similar to the DS path design, some defocusing has been chosen of the fiber w.r.t. the user's lens 1 in order to obtain a slightly diverging US beam which eases US alignment. Using thin lens analysis, the US beam diameter Dream2 at the PRA site with defocusing pi=1-v4/f; is
Dpeamz = 2 pr tana, E + fi & — 1)
The spot diameter D. at the photodiode PD at the PRA site after lens 2, with defocusing pz=x/f2>0 which enlarges the receiving Field-of-View half-angle (FoV) a, is
De=2ptana [fotp {a+ fi (5-1) ~ ff]
IDe — Dppl
MeT) with Dpp the PD's diameter, and tan a:=4/rwo (where A is the wavelength of the light, and wo is the radius of the Gaussian beam emerging from the transmitter’s single-mode fiber).
Assuming a uniform beam power profile and neglecting lens aberrations, with 4=20mm a US beam diameter Dpeam2=15mm needs a defocusing p1=28.6% at a user-ceiling distance d=20cm, and p1=2.53% at d=200cm. Fig. 3 shows how the beam-to-PD power coupling factor 7 and the half-angle FoV a then depend on the defocusing pz. Accepting 7>-10dB at d=200cm implies p2<27% and thus
FoV a< 20deg. which exceeds the FoV for the DS Rx (about 10deg.), as required.
The US beam is steered in 2D by displacing the output fiber of the US transmitter laterally over Ax and/or Ay with respect to the axis of the US lens 1, as shown in Fig. 4.
The xy translator stage uses NEMA11 stepper motors, driven by an
Arduino controller board. The effective lens aperture of the lens limits the displacement
Ax to AX max = 3 Diens" fi(1-p:) tana . The achievable maximum US steering angle is
Omax = atan Des -(1-po) tana), and the lateral steering resolution at the US Rx site at the ceiling is dx.=ex- (d/f1-1) where & is the resolution of the xy stepper motor stage.
E.g., with a Diens:=11.5mm and fi=20mm with p:=0.0271 for a US beam diameter
Dpeam2=15mm, and &=30nm, the steering resolution 6x.=2.97mm and max. US steering angle gmsx=10.8 deg. which exceeds the max. DS steering angle of 10 deg. as required.
By scanning the US beam over the RR ring around the US Rx aperture, alignment of the US beam is automated. Fig. 6 illustrates the scanning in x- and y-direction, and Fig. 7 shows the analytical and experimental results of monitoring the reflected beam’s power at the US Tx site.
Using the monitored power results { pi } taken at vector positions n= 6) the center of gravity(CoG) vector of the RR ring is i 1 N N w= _ (Xcosy _ _* CRY _
CoG = (ee) = pp (1) with Prot Dp t-1 t=1
As the US Rx aperture is centered inside the RR ring, localizing the
CoG by scanning also yields automatic alignment of the US beam into this aperture.
With arbitrary start position of the scanning, and a scan step size of 6mm at the RR ring, the accuracy of the beam alignment w.r.t. the US Rx aperture of @25mm is better than 40um, well within the required precision.
The CoG algorithm requires that the beam spot preserves its circular shape during the RR scanning, hence the US lens should have minimal off-axis aberrations. Ray tracing done on several lens types shows that a triplet lens with =20mm gives much lower aberrations than e.g. a commonly used planoconvex lens; see Fig. 5 (7 is fraction of power captured by 315mm aperture (red circle); fg ellipticity of the spot, which indicates spot deformation and must be low for efficient lens coupling to the PD in the US Rx).
Fig. 8 shows the bidirectional OWC lab system. It adds the US part to a known DS GbE video streaming setup with a reach of 2m. By A-tuning, the 10dBm &10cm DS beams are 2D steered by an AWGR-based diffractive unit. Using a 4x4 PD matrix and @50mm f=10mm Fresnel lens the DS-Rx has a FoV=10deg..
In the new US link, a 2dBm @15mm US beam at A~1.5um is launched using a triplet lens with /=20mm. The beam is mechanically 2D steered by a NEMA11 xy stepper motor stage, controlled by an Arduino board; the board performs the CoG automatic beam alignment algorithm aided by monitoring the reflected power from the
RR ring at the user site with three low-bandwidth &1mm photodiodes. The US-Rx has a @25mm Fresnel lens with /=5mm, achieving a FoV~12deg. GbE media converters (MCs) are used to convert the bidirectional GbE data from optical to RJ45/USB signals.
Our CoG US beam alignment algorithm successfully achieved US connectivity within 10s for a step size of 6mm, and even within 4s for 7.5mm. Within the FoV range, bidirectional TCP test by Iperf measurements showed ~940Mbit/s in DS and ~939Mbit/s in US, without packet loss. Unidirectionally, Iperf in UDP test showed ~958Mbit/s US with 0.18% packet loss.
GbE bidirectional OWC transmission using automatic self-alignment of the upstream beam has been demonstrated for high-density user connections. TCP measurements show 940Mbit/s transfer speeds per user with a FoV~10 deg.
The present invention has now been described in accordance with several exemplary embodiments, which are intended to be illustrative in all aspects, rather than restrictive.
Thus, the present invention is capable of many variations in detailed implementation, which may be derived from the description contained herein by a person ordinary skilled in the art.
All such variations are considered to be within the scope and spirit of the present invention as defined by the following claims and their legal equivalents.
Claims (15)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2032214A NL2032214B1 (en) | 2022-06-17 | 2022-06-17 | Bi-directional all-optical wireless communication system with autonomous optical beam steering. |
| PCT/NL2023/050339 WO2023244115A1 (en) | 2022-06-17 | 2023-06-16 | Bi-directional all-optical wireless communication system with autonomous optical beam steering |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2032214A NL2032214B1 (en) | 2022-06-17 | 2022-06-17 | Bi-directional all-optical wireless communication system with autonomous optical beam steering. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2032214B1 true NL2032214B1 (en) | 2024-01-05 |
Family
ID=83902718
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2032214A NL2032214B1 (en) | 2022-06-17 | 2022-06-17 | Bi-directional all-optical wireless communication system with autonomous optical beam steering. |
Country Status (2)
| Country | Link |
|---|---|
| NL (1) | NL2032214B1 (en) |
| WO (1) | WO2023244115A1 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020033982A1 (en) * | 2000-09-20 | 2002-03-21 | Dewenter William G. | Optical wireless network with direct optical beam pointing |
| US9118420B2 (en) * | 2008-09-01 | 2015-08-25 | Samsung Electronics Co., Ltd | Method and apparatus for optical communication using a retro-reflector |
| CN112235045A (en) * | 2020-09-22 | 2021-01-15 | 西安理工大学 | Alignment device and alignment method for non-direct-view free space optical communication |
| WO2022023081A1 (en) * | 2020-07-28 | 2022-02-03 | Signify Holding B.V. | Optical alignment system for optical communication devices |
-
2022
- 2022-06-17 NL NL2032214A patent/NL2032214B1/en active
-
2023
- 2023-06-16 WO PCT/NL2023/050339 patent/WO2023244115A1/en unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020033982A1 (en) * | 2000-09-20 | 2002-03-21 | Dewenter William G. | Optical wireless network with direct optical beam pointing |
| US9118420B2 (en) * | 2008-09-01 | 2015-08-25 | Samsung Electronics Co., Ltd | Method and apparatus for optical communication using a retro-reflector |
| WO2022023081A1 (en) * | 2020-07-28 | 2022-02-03 | Signify Holding B.V. | Optical alignment system for optical communication devices |
| CN112235045A (en) * | 2020-09-22 | 2021-01-15 | 西安理工大学 | Alignment device and alignment method for non-direct-view free space optical communication |
Non-Patent Citations (4)
| Title |
|---|
| KINGSBURY R W ET AL: "Fast-steering solutions for cubesat-scale optical communications", PROCEEDINGS OF SPIE; [PROCEEDINGS OF SPIE ISSN 0277-786X VOLUME 10524], SPIE, US, vol. 10563, 14 November 2017 (2017-11-14), pages 105630G - 105630G, XP060098781, ISBN: 978-1-5106-1533-5, DOI: 10.1117/12.2304229 * |
| KOONEN TON ET AL: "Fully Passive User Localization for Beam-Steered High-Capacity Optical Wireless Communication System", JOURNAL OF LIGHTWAVE TECHNOLOGY, IEEE, USA, vol. 38, no. 10, 12 March 2020 (2020-03-12), pages 2841 - 2847, XP011788467, ISSN: 0733-8724, [retrieved on 20200514], DOI: 10.1109/JLT.2020.2980428 * |
| TROTTER CADE ET AL: "Gigabit Indoor Free-Space Optical Communication Enhanced by Dynamic Beam Control", 2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), OSA, 9 May 2021 (2021-05-09), pages 1 - 2, XP034002153, DOI: 10.1364/CLEO_SI.2021.SM4A.2 * |
| ZOU FAN ET AL: "Adaptive Laser Aiming Through 2 km Horizontal Atmosphere with Precise-Delayed SPGD Algorithm", JOURNAL OF RUSSIAN LASER RESEARCH, CONSULTANTS BUREAU, NEW YORK, NY, US, vol. 42, no. 4, 1 July 2021 (2021-07-01), pages 462 - 467, XP037504860, ISSN: 1071-2836, [retrieved on 20210703], DOI: 10.1007/S10946-021-09983-0 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2023244115A1 (en) | 2023-12-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Koonen et al. | Ultra-high-capacity wireless communication by means of steered narrow optical beams | |
| AU2002242101B2 (en) | Agile multi-beam free-space optical communication apparatus | |
| Koonen et al. | Fully passive user localization for beam-steered high-capacity optical wireless communication system | |
| US8948601B2 (en) | Method and system for indoor wireless optical links | |
| US7292788B2 (en) | Multi-beam laser communications system and method | |
| AU2002242101A1 (en) | Agile multi-beam free-space optical communication apparatus | |
| US9246589B2 (en) | Two-dimensional optical beam steering module | |
| CN104185961A (en) | High speed free-space optical communications | |
| US6445496B1 (en) | Point-to-multipoint free-space wireless optical communication system | |
| US6944403B2 (en) | MEMS based over-the-air optical data transmission system | |
| US20020081060A1 (en) | MEMS based over-the-air optical data transmission system | |
| NL2032214B1 (en) | Bi-directional all-optical wireless communication system with autonomous optical beam steering. | |
| Soltani et al. | Terabit indoor laser-based wireless communications: LiFi 2.0 for 6G | |
| Koonen et al. | Bi-directional all-optical wireless communication system with optical beam steering and automatic self-alignment | |
| US20040208597A1 (en) | Free-Space optical transceiver link | |
| Koonen et al. | Bi-directional all-optical wireless gigabit Ethernet communication system using automatic self-aligned beam steering | |
| Pham et al. | Design and implementation of mobility management for indoor beam-steered infrared light communication system | |
| US7590352B2 (en) | Access method for data packet networks | |
| CN110178060A (en) | Two-dimentional light beam steering module | |
| CN112596173A (en) | Optical signal transmitter | |
| Pham et al. | Auto-Aligned OWC Receiver for Indoor Mobile Users using Gradient Descent Algorithm | |
| Koonen et al. | Recent advances in ultra-broadband optical wireless communication | |
| Koonen et al. | Indoor optical/radio wireless communication-demonstration of high-def video streaming using steerable infrared beams | |
| Mekonnen et al. | Circumventing LoS blocking in beam-steered optical-wireless systems with real-time tracking and handover | |
| Koonen et al. | High-density indoor optical wireless communication by directed narrow beams |