Retainer for optical transmitter to provide beam cutting

Abstract

A holder (100) comprising: a fastening device (110) configured to secure an optical transmitter for optical wireless communication; and a mechanical side shield (120) configured to shield a portion of a beam footprint of the optical transmitter with the straight cutout.

Description

Technical Field

[0001] The present invention relates to the field of optical wireless communications, such as Li-Fi communications. More particularly, various devices, systems and methods are disclosed herein related to a holder for securing an optical transmitter and providing beam cutting. Background Art

[0002] To enable more and more electronic devices (such as laptops, tablets and smartphones) to connect wirelessly to the Internet, wireless communications face unprecedented requirements for data rates and link quality, and these requirements continue to grow year by year in view of the emerging digital revolution related to the Internet of Things (IoT). Radio frequency technologies (such as Wi-Fi) have limited spectrum capacity and are unable to meet this revolution.

[0003] At the same time, optical wireless communications (OWC) have attracted increasing attention due to their inherent security enhancements and ability to support higher data rates over available bandwidths in the visible, ultraviolet (UV) and infrared (IR) spectra. Depending on, for example, the wavelength used, this technology may also be referred to as coded light, light fidelity (LiFi), visible light communications (VLC), or free space optics (FSO). As compared to Wi-Fi, OWC or Li-Fi is directional and shielded by light-blocking materials, which provides it with the potential to deploy a larger number of access points in user-dense areas by spatially reusing the same bandwidth. These key advantages over wireless radio frequency communications make OWC or Li-Fi a promising and secure solution to relieve pressure on the crowded radio spectrum used for IoT applications and indoor wireless access. Other possible benefits of Li-Fi may include guaranteed bandwidth for specific users and the ability to operate safely in areas that are otherwise susceptible to electromagnetic interference. Therefore, Li-Fi is a very promising technology for enabling the next generation of immersive connectivity.

[0004] Due to the line-of-sight requirement of optical wireless communications, the coverage area of ​​a single optical cell is typically limited, as compared to RF-based cells. Therefore, in order to provide adequate coverage in a certain area, multiple optical cells are typically deployed. However, adjacent optical access points (APs) may interfere with each other if there is overlap between the wavelengths used by two access points (APs) and / or if they transmit simultaneously.

[0005] One way to enable two wireless optical networks to coexist in the same area without interference is to use separate wavelengths for each network. However, this solution brings several constraints and disadvantages:

[0006] - Limitation on the number of "off-the-shelf" wavelengths in the IR spectrum: only a few LEDs can provide reasonably high power to guarantee large coverage (i.e. 850nm and 940nm);

[0007] - the need for an IR filter (low-pass, high-pass or band-pass) to be placed in front of the optical receiver to provide sufficient attenuation of unwanted wavelengths, and these IR filters are expensive;

[0008] - Performance degradation with respect to temperature: LEDs typically exhibit a peak wavelength shift with respect to temperature (ie, a wavelength shift of 25 nm over a temperature change of 70° C.), which results in a loss of optical received power due to the fixed cut-off frequency of the IR filter.

[0009] Another way to enable two wireless optical networks to coexist in the same area without interference is to apply a channel access control method called time division multiple access (TDMA). Some baseband modules for optical wireless communications have controllable time slots. For example, by synchronizing the baseband modules, it is possible to schedule transmissions from multiple adjacent optical APs by allowing only one optical AP to transmit at a time.

[0010] US 1 0 992 380 B2 relates to a system for transmitting data between a rotating element and a fixed element by wireless optical communication.

[0011] JPH0897768A relates to an optical signal transmitting part that amplifies a received optical signal up to a specified level and transmits the signal, an optical signal receiving part that receives / detects a modulated optical signal, which are provided to the upper and lower parts of an optical repeater, wherein the received optical signal is amplified up to a specified level and transmitted in space, and an optical diffusion plate for diffusing the transmitted optical signal in space, which is set at an appropriate position of the optical signal transmitting part. Summary of the invention

[0012] In order to provide good coverage in a certain area, multiple optical cells are usually deployed for accessing one or more external networks. As mentioned above, the coexistence of multiple optical APs in the same area can be solved by using wavelength division multiplexing (WDM) or TDMA between multiple optical APs. However, this solution introduces additional system complexity.

[0013] In view of the above, the present disclosure relates to an apparatus and system for providing a simple and effective solution to control beam shape for interference avoidance in an optical wireless communication system. More particularly, the objects of the present invention are achieved by an optical access point as claimed in claims 1 and 6, respectively.

[0014] According to a first aspect of the present invention, an optical access point is provided. An optical access point comprises: an optical transceiver configured to perform optical wireless communication with a terminal device; and a holder comprising a fastening device configured to fix an optical transmitter for optical wireless communication, and a mechanical side shield comprising straight edges for shielding a portion of a beam coverage area of ​​the optical transmitter with a straight cutout.

[0015] The mechanical side shield is made of a light blocking material such as wood, plastic and metal that is opaque to light. A portion of the light beam emitted by the optical transmitter is blocked by the mechanical side shield with a straight cut.

[0016] The holder can be placed on a support surface, such as on a floor, a table or another piece of furniture. Alternatively, the holder can be used to fix the optical transmitter on a mounting surface, such as for hanging the optical transmitter from a ceiling. The holder can then include additional fastening means for this function.

[0017] The holder may also be used to secure the optical transceiver to produce beam cutting to avoid both uplink interference and downlink interference between adjacent optical communication zones.

[0018] The mechanical side shield includes at least one straight edge for shielding a portion of the beam footprint of the optical transmitter with a straight cutout.

[0019] Preferably, the mechanical side shield is rectangular in shape.

[0020] Considering the typical tapered beam, it is preferred to make the mechanical side shield rectangular in shape in order to provide a straight optical cut across the beam footprint.

[0021] If the optical cut follows a straight line, alternative shapes can also be used. For example, one or more sides of the mechanical side shield can also be curved.

[0022] Beneficially, the mechanical side shields have an adjustable size and / or orientation.

[0023] Considering that different light sources and different lenses may be used in the optical transmitter, it is desirable that the holder may provide more flexibility.

[0024] In one option, the mechanical side shields may have adjustable dimensions, such as the mechanical side shields further comprising folding or sliding portions.

[0025] In another option, the mechanical side shields may have an adjustable orientation. And then, the portion of the blocked beam area as compared to the maximum beam area supported by the optical transmitter may be easily controlled by adjusting the orientation of the mechanical side shields.

[0026] These two options can be used independently or in combination to meet different application scenarios, such as different layouts of the deployment area, or different optical transmitters including different light sources and / or lenses.

[0027] In one arrangement, the fastening means is configured to secure the optical transmitter in an inclined position with respect to a surface perpendicular to a mounting or supporting surface of the holder.

[0028] The tilt position may be determined based on the coverage area to be achieved, the beam angle of the optical transmitter, and the distance from the optical transmitter to the target terminal device.

[0029] As an example, when the optical transceiver has a beam angle of + / - 35 degrees, the tilt angle of the transceiver is preferably 30 degrees from the vertical direction to achieve vertical communication as the transceiver.

[0030] The tilt angle may be adjustable so that the tilt position may be reconfigured depending on the actual beam angle to be used and actual deployment requirements.

[0031] In one option, the tilt angle of the fastening device may be controlled independently of the orientation of the machine side shield. In another option, the machine side shield may be coupled to the fastening device, and then the tilt angle of the fastening device will also determine the orientation of the machine side shield.

[0032] Advantageously, the fastening means is configured to removably secure the optical transmitter.

[0033] The holder can be permanently fixed to a certain mounting surface or support surface. The optical transmitter is then conveniently placed in a removable manner in the fastening device.

[0034] According to a second aspect of the present invention, an optical access point is provided. An optical access point comprises: more than one optical transceiver configured to perform optical wireless communication with one or more terminal devices; and a holder comprising a fastening device configured to fix more than one optical transmitter for optical wireless communication, and more than one mechanical side shield, wherein each mechanical side shield comprises a straight edge for shielding a portion of a beam coverage area of ​​a separate optical transmitter among the more than one optical transmitter with a straight cutout.

[0035] In order to provide coverage of an area as complete as possible, it is beneficial that two or more adjacent optical cells can be close to each other, but with reduced mutual interference. Therefore, the holder according to the second aspect can be used to meet this requirement, so that two or more adjacent optical transmitters are fixed to the same holder, and the beam area of ​​the individual optical transmitters is controlled by the corresponding mechanical side shielding.

[0036] Depending on the target coverage area and the number of optical transmitters or transceivers to be deployed, the holder can be configured as a double holder, a triple holder or a multi-holder. Which type of holder or combination of different types of holders to use will depend on the layout of the target coverage area.

[0037] The holder may also be used to secure more than one optical transceiver to create beam cutting for more than one optical transceiver, thereby avoiding both uplink interference and downlink interference between any two adjacent optical communication zones.

[0038] Preferably, each machine side shield is rectangular in shape.

[0039] Beneficially, each machine side shield has an adjustable size and / or orientation.

[0040] In one arrangement, the fastening means is configured to secure each optical transmitter in an inclined position with respect to a surface perpendicular to a mounting or supporting surface of the holder.

[0041] Advantageously, the fastening means is configured to secure more than one optical transmitter to avoid overlap between light beam footprints of any two of the more than one optical transmitters.

[0042] Preferably, the fastening device is further configured to secure more than one optical transmitter to generate complete coverage of the target communication area.

[0043] By controlling one or more of the tilt angle of the optical transmitter, the size and / or orientation of more than one mechanical side shield, the fastening device can be configured to secure more than one optical transmitter to avoid overlap between the beam coverage areas of any two optical transmitters and provide complete optical wireless communication coverage of the target area.

[0044] Advantageously, the fastening means are configured to removably secure each optical transmitter.

[0045] The holder can be permanently fixed to a certain mounting surface or support surface. The optical transmitter is then conveniently placed in a removable manner in the fastening device.

[0046] According to a third aspect of the present invention, an optical access point is provided. The optical access point comprises: an optical transceiver configured to perform optical wireless communication with a terminal device; and a holder according to the present invention configured to fix the optical transceiver and shield a portion of a beam coverage area of ​​the optical transceiver.

[0047] In the following, the term "access point" of the Li-Fi system is used to refer to a logical access device that can be connected to one or more physical access devices (e.g., optical transceivers). Such physical access devices can usually (but not necessarily) be located at the luminaire, and the logical access point can be connected to one or more physical access devices, each of which is located at one or more luminaires. The access point can in turn serve one or more network devices or terminal devices associated therewith.

[0048] Optical wireless communication (OWC) access points or Li-Fi access points provide electronic devices or terminal devices within the corresponding optical cell with access to the external network via an optical wireless link. OWC access points can also support bidirectional optical links with more than one terminal device at the same time.

[0049] Optical wireless communication can be carried out in the visible light, ultraviolet (UV) and infrared (IR) spectra. Therefore, optical wireless communication can also be referred to as Li-Fi communication or visible light communication (VLC). The optical transceiver may include at least a light source for optical data transmission and a light detector for optical data reception. The light source or light emitter may be one of a light emitting diode (LED), a laser diode, a vertical cavity surface emitting laser (VCSEL) or an edge emitting laser diode (EELD). Preferably, the light source includes at least one of an LED and a VCSEL. The light detector (also called a photodetector or a photoelectric sensor) is a photodiode, which may be a PIN diode, an avalanche photodiode (APD) or a photomultiplier tube.

[0050] According to another aspect of the present invention, an optical access point is provided. The optical access point comprises: more than one optical transceiver configured to perform optical wireless communication with one or more terminal devices; and a holder according to the present invention configured to fix the more than one optical transceiver and shield a portion of each light beam coverage area of ​​a single optical transceiver among the more than one optical transceiver.

[0051] With the help of a double holder, a triple holder or a multi-holder according to the present invention, the optical AP may also include more than one optical transceiver.

[0052] Advantageously, the optical access point further comprises more than one communication interface connected to more than one network; wherein at least two of the more than one optical transceivers are configured to provide connection to different ones of the more than one network.

[0053] In some application scenarios, terminal devices in the same area may need to access different external networks, which may have different domains, security levels and / or priority levels. Example use cases include scenarios where accessibility needs to be provided to both public and private networks in the same area (such as hotels, public sectors, and enterprises). Other applications include military and defense, such as providing accessibility to multiple networks with different security levels. In order to provide connections to these multiple external networks in the same area, one or more of the more than one optical transceiver can be connected to different external networks.

[0054] Different external networks may be wired networks or wireless networks. It is also possible that one of the external networks is a wired network and the other of the external networks is a wireless network. The wired network may be Ethernet, a power line communication (PLC) network, or a plastic optical fiber (POF) network. The wireless network may be based on a millimeter wave communication system or a 5G cellular network. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In the drawings, similar reference numerals are used throughout the different Figure 1 Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0056] Figure 1 An example of a retainer is illustrated;

[0057] Figure 2 A picture showing an example of a retainer;

[0058] Figure 3 An example of a retainer is illustrated;

[0059] Figure 4 A picture showing an example of a retainer;

[0060] Figure 5 A block diagram of an optical access point is shown;

[0061] Figure 6 A block diagram of an optical access point is shown;

[0062] Figure 7 A block diagram of an optical access point is shown;

[0063] Figure 8 illustrates the coverage area of ​​an optical transceiver on a surface at different distances from the optical transceiver;

[0064] Fig. 9 illustrates an interference scenario between two adjacent optical cells in a conventional system;

[0065] Fig.10The diagram illustrates the deployment of optical cells in a conventional system to provide full coverage;

[0066] Fig.11 An example installation of an optical transceiver on a holder is shown;

[0067] Fig.12 An example of the resulting coverage area of ​​two adjacent optical cells is shown;

[0068] Fig.13 shows measurements of achievable data rates at different distances from an access point and at different locations in the coverage area of ​​two adjacent optical cells; and

[0069] Fig.14 An example of deploying optical cells in a rectangular area is illustrated. DETAILED DESCRIPTION

[0070] The embodiments set forth below represent information that enables those skilled in the art to practice these embodiments. After reading the following description in accordance with the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize the applications of these concepts that are not particularly proposed herein. It should be understood that these concepts and applications fall within the scope of the present disclosure.

[0071] Figure 1 An example of a holder 100 is illustrated. The holder 100 comprises a fastening device 110 configured to fix an optical transmitter for optical wireless communication and a mechanical side shield 120 configured to shield a portion of a beam footprint of the optical transmitter with a straight cutout.

[0072] exist Figure 1 In the example shown in , the holder 100 includes additional fastening means for fixing the holder to a mounting surface (such as for hanging the holder and the optical transceiver from a ceiling). In alternative scenarios, when the holder is placed on a support surface (such as on a table), the holder may not require additional fastening means.

[0073] The holder 100 may also be used to secure an optical transceiver to produce beam cutting to avoid both uplink interference and downlink interference between adjacent optical communication zones.

[0074] Figure 2 Shown with Figure 1 FIG. 1 is a picture of the same holder 100 as in FIG. 1 . The beam shape of the optical transmitter is indicated by the shading. It can be seen that the mechanical side shield 120 provides a straight cut on one side of the beam.

[0075] Figure 3An example of a holder 200 is shown. The holder 200 includes a fastening device 210 configured to fix more than one optical transmitter for optical wireless communication, and more than one mechanical side shields 220, 220', wherein each mechanical side shield is configured to shield a portion of a beam footprint of a separate optical transmitter among the more than one optical transmitter with a straight cutout.

[0076] The holder 200 may also be used to secure more than one optical transceiver to create beam cutting for more than one optical transceiver, thereby avoiding both uplink interference and downlink interference between any two adjacent optical communication zones.

[0077] This example shows a double holder 200. As mentioned above, it can also be a triple holder or a multi-holder 200 to fix three or more optical transceivers. Which type of holder or combination of different types of holders to use will depend on the layout of the target coverage area.

[0078] exist Figure 3 In the example shown in , the dual holder 200 includes additional fastening means for fixing the holder to a mounting surface (such as for hanging the holder 200 and the optical transceiver from a ceiling). In an alternative scenario, when the holder 200 is placed on a support surface (such as on a table), the holder 200 may not have additional fastening means.

[0079] Figure 4 Shown with Figure 3 2. The beam shape of the optical transmitter is indicated by the shading. It can be seen that the mechanical side shields 220, 220' provide straight cuts on adjacent edges of the beams from the two optical transceivers.

[0080] Figure 5 1 shows a block diagram of an optical access point 300. The optical access point 300 includes an optical transceiver 350 configured to perform optical wireless communication with a terminal device, and a holder 100 according to the present invention configured to fix the optical transceiver 350 and shield a portion of the optical beam coverage area of ​​the optical transceiver 350.

[0081] The optical transceiver 350 may include at least a light source for optical data transmission and a light detector for optical data reception. The light source or light emitter may be one of a light emitting diode (LED), a laser diode, a vertical cavity surface emitting laser (VCSEL), or an edge emitting laser diode (EELD). Preferably, the light source includes at least one of an LED and a VCSEL. The light detector (also called a photodetector or a photoelectric sensor) is a photodiode, which may be a PIN diode, an avalanche photodiode (APD), or a photomultiplier tube.

[0082] Figure 6 4 shows a block diagram of an optical access point 400. The optical access point 400 includes more than one optical transceiver 350, 350' and a holder 200 according to the present invention. The optical transceiver 350, 350' is configured to perform optical wireless communication with one or more terminal devices. The holder 200 is configured to fix more than one optical transceiver 350, 350' and shield a portion of each light beam coverage area of ​​a single optical transceiver among the more than one optical transceiver 350, 350'.

[0083] Figure 7 A block diagram of an optical access point 400 according to a further example is shown. The optical access point 400 further comprises more than one communication interface 460, 460' connected to more than one network; and at least two of the more than one optical transceivers 350, 350' are configured to provide connection to different ones of the more than one network.

[0084] In some application scenarios, terminal devices in the same area may need to access different external networks, which may have different domains, security levels and / or priority levels. Example use cases include scenarios where accessibility needs to be provided to both public and private networks in the same area (such as hotels, public sectors and enterprises). Other applications include military and defense, such as providing accessibility to multiple networks with different security levels.

[0085] More than one external network may be a wired network or a wireless network. It is also possible that one of the external networks is a wired network and another of the external networks is a wireless network. The wired network may be an Ethernet, a power line communication (PLC) network, or a plastic optical fiber (POF) network. The wireless network may be based on a millimeter wave communication system or a 5G cellular network.

[0086] Figure 8 An example of the coverage area of ​​an optical transceiver on a surface at different distances from the optical transceiver is illustrated. In this example, a circular beam is assumed, and the nominal radius of the coverage area of ​​the optical cell increases with the distance from the optical transceiver. The coverage area may also have other shapes depending on the beam shape used by the system. Of course, the data rate to be provided to a terminal device located on a certain surface will decrease accordingly with increasing distance from the optical transceiver. In this sense, deploying the AP farther away from the target terminal device allows a larger coverage area, but a lower data rate may be supported.

[0087] In the example of an optical wireless communication (OWC) system, a ceiling mounted OWC access point (AP) may be integrated with a luminaire having a general lighting function. This may be a good placement for the AP function, since the luminaire is also preferably placed to evenly and completely illuminate the space. To ensure coverage, the light beams from adjacent APs will have overlapping areas, and when adjacent APs transmit simultaneously, terminal devices (EDs) located in such overlapping areas may experience interference. Similarly, these EDs may also produce overlapping beams on the AP side and cause mutual interference in the uplink.

[0088] Fig. 9 The diagram illustrates an interference scenario between two adjacent optical cells in a conventional system. Optical access points AP1 and AP2 include optical transceivers TRX1 and TRX2, respectively, and the separation distance between the two transceivers is indicated by s in the figure. The distance between the optical transceiver and the target terminal device is d. Area A represents a coverage area without overlap, and area B represents an overlapping area, or interference zone. The radius of a conventional optical cell is denoted by r. MAX The width of the interference area is indicated by b, and correspondingly, the radius towards the neighboring cell in the absence of interference is a, which is equal to r MAX -b.

[0089] Fig.10 The diagram illustrates the deployment of optical cells in a conventional system to provide full coverage. Each circle indicates an optical cell. And in order to provide full coverage of a rectangular shaped area, 12 optical cells are deployed. When a terminal device is located in an overlapping area between any two or more adjacent optical cells, it will experience interference from two or more adjacent APs. In addition, it can be seen that in such a conventional system, there is always a trade-off in the design of the deployment between coverage and interference. In order to achieve full coverage, overlapping areas or interference areas are inevitable.

[0090] Interference avoidance between multiple APs can be handled by using wavelength multiplexing or time division multiple access (TDMA).However, these conventional interference avoidance techniques have certain limitations and disadvantages such that they add additional complexity and overhead to the system.

[0091] Fig.11 An example mounting of an optical transceiver 350 on a holder 100 is shown. Black dots exemplarily indicate preferred locations for placing the light source and light sensor of the optical transceiver 350. Dashed lines show that the mechanical side shield 120 provides the optical transceiver 350 with perpendicular optical cuts on outgoing and incoming light beams.

[0092] Fig.12An example of the resulting coverage area of ​​two adjacent optical cells according to the present invention is shown. The juxtaposition of two adjacent coverage areas (area 1 and area 2) is achieved by using a dual holder 200 with two optical transceivers. When the two optical transceivers are connected to different external networks via separate communication interfaces 460, area 1 and area 2 will also provide different optical networks (such as two different LiFi networks) for terminal devices located in adjacent areas.

[0093] Fig.13 The results show the coverage of different distances to the access point and in the coverage area of ​​two adjacent optical cells (such as in Fig.12 1 and 2). In this example, the maximum data rate to be supported is 200 Mbps. As shown in the figure, the data rate to be provided to the terminal device located on a certain surface will decrease as the distance from the optical transceiver increases. In this sense, deploying the AP further away from the target terminal device allows a larger coverage area, but lower data rates can be supported. With the dual retainer, two optical cuts are provided on adjacent edges of two optical cells. It can be seen that an advantage of the disclosed solution is that the optical cut provided by the mechanical side shield 120 is independent of the distance between the EP and the transceiver, especially when the optical cut is vertical.

[0094] Fig.14 An example of deploying optical cells in a rectangular area is illustrated. Depending on the shape and / or size of the entire surface to be covered by the optical wireless communication, different combinations of single transceiver holders 100, dual transceiver holders or multiple transceiver holders 200 can be used. Further adjustments can be made by changing the size and / or orientation of the mechanical side shields of one or more of the holders, or by adjusting the fastening means of one or more of the holders to change the tilt position of the corresponding optical transceiver.

[0095] In this example with a rectangular coverage area, three APs 400 (each with a dual transceiver holder 200) are deployed in the middle of the zone, while three APs 300 (each with a single transceiver holder 100) are deployed on the top and bottom edges of the zone, respectively.

[0096] In this example, the APs 300, 400 are placed in luminaires on the ceiling with a horizontal spacing of 1.8m and a vertical spacing of 3.6m in the above picture. When the shape and / or size of the room does not match the standard or default beam shape of the optical transceiver, further aforementioned adjustments can be made, such as adding more transceivers in the AP, changing the shape of the beam, adjusting the tilt position of the transceiver, changing the size and / or orientation of the mechanical side shield, etc.

Claims

1. An optical access point (300), comprising: an optical transceiver (350) configured to perform optical wireless communication with a terminal device; and A retainer (100) comprising: - a fastening device (110) configured to fix an optical transmitter (350) for optical wireless communication, and - A mechanical side shield (120) comprising straight edges for shielding a portion of the beam footprint of an optical transmitter (350) with a straight cutout.

2. The optical access point (300) of claim 1, wherein the mechanical side shield (120) is rectangular in shape.

3. The optical access point (300) according to claim 1 or 2, wherein the mechanical side shield (120) has an adjustable size and / or orientation.

4. The optical access point (300) according to any of the preceding claims, wherein the fastening means (110) is configured to secure the optical transmitter in a position inclined with respect to a surface perpendicular to a mounting or supporting surface of the holder (100).

5. The optical access point (300) according to any one of the preceding claims, wherein the fastening means is configured to detachably secure the optical transmitter.

6. An optical access point (400), comprising: more than one optical transceiver (350, 350') configured to perform optical wireless communications with one or more terminal devices; and A retainer (200) comprising: - a fastening device (210) configured to secure more than one optical transmitter for optical wireless communication, and - more than one mechanical side shield (220, 220'), wherein each mechanical side shield comprises straight edges for shielding a portion of a beam footprint of a separate optical transmitter among the more than one optical transmitter with a straight cutout.

7. The optical access point (400) of claim 6, wherein each mechanical side shield (220, 220') is rectangular in shape.

8. The optical access point (400) of claim 6 or 7, wherein each mechanical side shield (220, 220') has an adjustable size and / or orientation.

9. The optical access point (400) according to any of the preceding claims 6-8, wherein the fastening means (210) is configured to secure each optical transmitter in a tilted position with respect to a surface perpendicular to a mounting or supporting surface of the holder.

10. The optical access point (400) according to any one of the preceding claims 6-9, wherein the fastening device (210) is configured to fix the more than one optical transmitter to avoid overlap between light beam footprints of any two optical transmitters among the more than one optical transmitters.

11. The optical access point (400) of claim 10, wherein the fastening device (210) is further configured to secure the more than one optical transmitters to generate complete coverage of a target communication area.

12. The optical access point (400) according to any of the preceding claims 6-11, wherein the fastening means (210) is configured to detachably secure each optical transmitter.

13. The optical access point (400) of any of the preceding claims 6-12, further comprising more than one communication interface (460, 460') connected to more than one network; wherein at least two of the more than one optical transceivers (350, 350') are configured to provide connection to different networks among the more than one networks.

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