APPARATUS AND METHOD FOR EXCHANGING DATA IN A HYBRID OPTICAL-WIRELESS COMMUNICATION SYSTEM - Patent application

Abstract

In an optical wireless communication (OWC) system, the apparatus (200) is configured to operate in a first mode in which the apparatus enables a first functionality of acting as a bridge device between an OWC access point (400) and a first end device of one or more end devices (300a, 300b, 300c, 300d) or in a second mode in which the apparatus enables a second functionality of relaying data between the first end device and a second end device of the one or more end devices (300a, 300b, 300c, 300d). The apparatus (200) communicates with the OWC access point (400) by a first type of optical wireless link (450) using a first modulation scheme and communicates with the first end device by a second type of optical wireless link (350) using a second modulation scheme. The first type of optical wireless link (450) has a wider beam angle than the second type of optical wireless link (350).

Description

[Technical field]

[0001] The present invention relates to the field of optical wireless communication networks, such as Li-Fi networks. In particular, various methods, apparatus, systems, and computer-readable media related to interoperability enhancement in hybrid optical wireless communication systems are disclosed herein. [Background technology]

[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 on data rates and link quality, which are increasing year by year in light of the new digital revolution related to the Internet-of-Things (IoT). Radio frequency technologies such as Wi-Fi have limited spectrum capacity to address this revolution. On the other hand, light fidelity (Li-Fi) has been attracting increasing attention for its intrinsic security enhancement and its capability to support higher data rates in the available bandwidth of the visible, ultraviolet (UV), and infrared (IR) spectrum. Furthermore, since Li-Fi is directional and shielded by light-blocking materials, it has the potential to deploy more access points in densely populated areas by spatially reusing the same bandwidth, compared to Wi-Fi. These key advantages over wireless radio frequency communications make Li-Fi a promising secure solution to ease the pressure on the crowded radio spectrum for IoT applications. Other advantages of Li-Fi include guaranteed bandwidth to specific users and the ability to operate securely in areas prone to electromagnetic interference. Therefore, Li-Fi is a very promising technology to enable the next generation of immersive connectivity.

[0003] There are several relevant terminologies in the field of lighting-based communication. Visible-light communication (VLC) transmits data faster than the persistence of the human eye by intensity-modulated light sources such as light-emitting diodes (LEDs) and laser diodes (LDs). Li-Fi is often used to embed signals in the light emitted by lighting sources such as everyday luminaires, e.g., indoor or outdoor lights, thus allowing the light from the luminaire to be used as a carrier of information. Thus, the light may include both a visible lighting contribution (typically the primary purpose of the light) to illuminate a target environment such as a room, and an embedded signal (typically considered a secondary function of the light) to provide information to the environment. In such cases, the modulation may typically be performed at a frequency high enough to exceed human perception, or at least such that visible temporary light artifacts (e.g., flicker and / or strobe artifacts, etc.) are weak enough at a frequency high enough that humans do not notice them or at least can tolerate them. In this way, the embedded signal does not affect the primary lighting function: the user only perceives the overall lighting, and not the effect of the data being modulated onto that lighting.

[0004] The IEEE 802.15.7 visible-light communication personal area network (VPAN) standard maps target applications to four topologies: peer-to-peer, star, broadcast, and coordinated. Optical Wireless PAN (OWPAN) is a more general term than VPAN that allows for non-visible light, such as UV and IR, for communication. Thus, Li-Fi is generally accepted as a spinoff of optical wireless communication (OWC) technology, utilizing a wide range of optical spectrum to support bidirectional data communication.

[0005] In Li-Fi systems, signals are embedded by modulating the properties of light, typically intensity, according to any of a variety of suitable modulation techniques. For high-speed communication, infrared (IR) communication is often used rather than visible light communication. Although ultraviolet and infrared radiation are invisible to the human eye, techniques utilizing these regions of the spectrum are similar, although variations may occur as a result of wavelength dependence, such as in the case of refractive index. In many cases, utilizing ultraviolet and / or infrared light is advantageous because these frequency ranges are invisible to the human eye, allowing more flexibility to be introduced into the system. Of course, ultraviolet quantum has a higher energy level compared to infrared and / or visible light, so the use of ultraviolet light may not be desirable in some situations.

[0006] Based on the modulation, the information in the light can be detected using any suitable light sensor or photodetector. For example, the light sensor may be a photodiode. The light sensor may be a dedicated photocell (point detector), an array of photocells, possibly with a lens, reflector, diffuser or phosphor converter (for low speed), or an array of photocells (pixels) and a lens to form an image on the array. For example, the light sensor may be a dedicated photocell included in a dongle that plugs into a user device such as a smartphone, tablet or laptop, or the sensor may be integrated and / or dual purpose, such as an array of infrared detectors originally designed for 3D face recognition. Either way, this allows applications running on the user device to receive data via the light.

[0007] In the following, the term "access point" of a Li-Fi system is used to denote a logical access device that can be connected to one or more physical access devices (e.g., optical transceivers). Such physical access devices may typically, but not exclusively, be located in luminaires, and a logical access point may be connected to one or more physical access devices each located in one or more luminaires. An access point may provide services to one or more associated network devices or end devices to form an optical cell.

[0008] WO2020240016 relates to an optical wireless communication (OWC) system including an access point (AP) including a plurality of OWC transmitters and a plurality of OWC receivers, a station (STA) including at least one retroreflector, and a controller configured to control the OWC AP transmitters and / or the OWC AP receivers, the controller being configured to process data representing at least one OWC signal transmitted by at least one of the OWC AP transmitters and received by at least one of the OWC AP receivers after being reflected by the at least one retroreflector.

[0009] WO2018054894 relates to a lighting system including at least one light source, a mobile system, e.g., a mobile device, and at least one further device. The mobile system includes a light sensor, a communication interface, and a processor. The mobile system is configured to receive from the light source a light emission in which an identifier is encoded, e.g., using visible light communication (VLC) technology, and to determine the identifier from the light emission. The mobile system is configured to join the group and communicate with at least one further device from the group of devices. Summary of the Invention [Problem to be solved by the invention]

[0010] Optical wireless communication or Li-Fi is proposed as a technology to complement or replace wired connections or radio frequency (RF) based wireless communication to enable electronic devices or end devices to support higher data rate communication for IoT applications. An optical wireless communication (OWC) access point, or Li-Fi access point, provides electronic devices or end devices in a corresponding optical cell with access to an external network via an optical wireless link. An OWC access point can also support bidirectional optical links with two or more end devices simultaneously.

[0011] The electronic device or part of the end device related to the optical wireless communication interface is typically referred to as a Li-Fi endpoint in such an OWC network. The Li-Fi endpoint may be connected to the end device as a separate entity via a cable, or may be partially or fully integrated into the end device. However, the complexity involved in supporting an OWC link with an infrastructure, such as an OWC access point, has proven to be a limiting factor given the form factor of the Li-Fi endpoint, preventing it from being fully integrated into small portable devices, such as smartphones. Apart from these mechanical constraints, power consumption and heat dissipation may also be an issue.

[0012] On the other hand, there are also clear advantages to enabling a peer-to-peer direct link between two mobile devices based on optical wireless communication technology. Such a direct wireless link can be a replacement for a wired connection leading to improved convenience. Compared to alternative peer-to-peer wireless links, such as radio frequency (RF) links based on Bluetooth technology, a direct optical wireless link offers significant advantages in terms of data rate and security. Such advantages can be highly attractive to smartphone users. However, as mentioned above, the integration of an OWC interface into a smartphone imposes stringent requirements on the OWC interface in terms of power consumption and form factor. A simplified design is highly desirable for ease of integration. [Means for solving the problem]

[0013] In view of the above, the present disclosure relates to a method, an apparatus, a system, a computer program and a computer readable medium for facilitating data exchange between peer-to-peer optical wireless links and OWC networks. In particular, the object of the present invention is achieved by an apparatus according to claim 1, an optical wireless communication system according to claim 13, a method for data exchange of the apparatus according to claim 14, and a computer program according to claim 15.

[0014] According to a first aspect of the present invention, there is provided an apparatus for exchanging data in an optical wireless communications (OWC) system, configured to operate in a first mode enabling a first functionality, where the apparatus acts as a bridge device between an OWC access point and a first end device of one or more end devices, or in a second mode enabling a second functionality, where the apparatus relays data between the first end device and a second end device of the one or more end devices. The apparatus includes a first optical transceiver configured to communicate with an OWC access point via a first type of optical wireless link using a first modulation scheme, a second optical transceiver configured to communicate with a first end device via a second type of optical wireless link using a second modulation scheme, and a hub component configured to select an operating mode from a set including a first mode, a second mode, and another mode in which both the first functionality and the second functionality are enabled, and to connect using the first optical transceiver and / or the second optical transceiver depending on the selected operating mode, wherein the first optical transceiver has a wider beam angle compared to the second optical transceiver.

[0015] Considering the challenge of enabling small portable devices, such as smartphones, to directly connect to an OWC network, an apparatus is disclosed that acts as an interface between the small portable device and the OWC network. Additionally, the apparatus can also act as a relay device between two small portable devices to extend the range beyond that of a direct optical wireless link, or enable such a link when the two devices are in positions where the optical beams cannot be easily aligned.

[0016] The first type of optical wireless link is used in infrastructure-based OWC networks to establish a connection between an end device and an optical access point. The second type of optical wireless link is used in peer-to-peer or device-to-device topologies to establish a connection between two end devices. The configuration of the first type of optical wireless link is more complex than that of the second type of optical wireless link because an optical access point is designed to support simultaneous communication with one or more end devices located within its coverage area.

[0017] The apparatus may operate in a first mode bridging a first and a second type of optical wireless link. In addition to operating in the first mode as a bridge device between an optical access point and a first end device, the apparatus may also operate in a second mode as a relay device between two end devices over a second type of optical wireless link. Thus, the apparatus includes a first optical transceiver and a second optical transceiver for communicating with the optical access point and the first end device, respectively. A hub component included in the apparatus is configured to select an operating mode of the apparatus, the operating mode being selected from a set including at least the first mode, the second mode, and a hybrid mode in which both the first mode and the second mode are enabled.

[0018] To avoid mutual interference between the first type optical wireless link and the second type optical wireless link, different wavelengths may be adopted among the different types of links. Furthermore, the second optical transceiver for the second type optical wireless link has a narrow beam angle compared to the first optical transceiver. Preferably, the second optical transceiver may be further positioned to point in a direction towards an intended end device to further reduce interference to another first or second type optical wireless link.

[0019] Advantageously, the first optical transceiver supports a higher data rate or a longer communication distance compared to the second optical transceiver.

[0020] An infrastructure-based optical wireless link typically outperforms a peer-to-peer direct link in terms of field of view (FoV), communication distance, data rate, and / or configuration flexibility. For example, the data rate supported by the first optical transceiver may be in the range of up to Gbps, and the data rate supported by the second optical transceiver may be less than 500 Mbps. The first optical transceiver may support a communication distance of more than 3 m, and the second optical transceiver may only support a communication distance of less than 3 m. The difference in data rate and communication distance may be due to different output power levels and / or modulation and coding schemes.

[0021] In a preferred setup, the hub component is further configured to determine the operating mode according to at least one of user input, predetermined configuration parameters, packets received by the first optical transceiver or the second optical transceiver, detection of the presence of one or more end devices, or input from the first optical transceiver or the second optical transceiver regarding detection of the presence of an OWC access point.

[0022] The device may operate with only one functionality enabled for power saving or multiple functionalities enabled simultaneously for increased flexibility. The decision of the operating mode may be influenced by one or more factors. For example, the device may be configured according to predefined configuration parameters related to an application scenario. The device may also be configured in response to user input, which may relate to user preferences or application needs.

[0023] Furthermore, the operation mode may be determined based on a packet received by the first optical transceiver or the second optical transceiver, in this example, the operation mode is remotely controlled. For example, a first end device wants to establish a direct optical wireless link with a second end device. However, the second end device is located at a distance outside the maximum communication distance supported by the first end device or at an angle outside the FoV of the direct link. The first end device may simply send a packet with a destination address of the second end device to the device. By checking the destination address, the device enables the second mode in the operation mode. Similarly, upon receiving a packet from another end device whose destination address is not a peer end device, the device enables the first mode in the operation mode and forwards the packet to the optical access point.

[0024] The operational mode may also be determined autonomously, such as following an input from the first optical transceiver or the second optical transceiver informing the hub component of the detection of the presence of one or more end devices, or the detection of the presence of an OWC access point. If no optical access point is detected by the first optical transceiver, the device may simply disable the first functionality in the operational mode. Thus, the first optical transceiver may enter a sleep mode. Thereafter, optical access point presence detection may be performed by the first optical transceiver from time to time, which may be according to a schedule or based on a trigger event, such as device movement.

[0025] In a preferred example, the first modulation scheme is by orthogonal frequency-division multiplexing (OFDM).

[0026] OFDM has a great advantage of being robust against harsh channel conditions, such as narrowband interference or frequency selective fading, and is therefore widely used as a digital multi-carrier modulation method in many communication systems. Also, by dividing the full band into multiple subcarriers, the system has the flexibility to apply different modulation and coding schemes to individual subcarriers, which can be used to maximize the capacity of the channel. In optical wireless communication, unipolar OFDM modulation techniques are typically adopted, such as ACO-OFDM, DCO-OFDM, ADO-OFDM and / or Flip OFDM.

[0027] Another advanced version is orthogonal frequency division multiple access (OFDMA). OFDMA is a multi-user extension of OFDM that allows simultaneous AP communication (uplink and downlink) with multiple end devices by allocating a subset of subcarriers. OFDMA provides more flexibility in providing different data rates or service qualities to different users, while high resource efficiency can be maintained despite such diversity.

[0028] Thus, in view of the capacity of an optical cell, it is efficient to adopt an OFDM or OFDMA modulation scheme for communication between an optical access point and one or more end devices.

[0029] However, from the end device perspective, OFDM may not be the most power efficient modulation scheme because the OFDM signal is applied near a DC bias, which reduces power efficiency.

[0030] In another preferred example, the second modulation scheme is by pulse-amplitude modulation (PAM).

[0031] PAM is characterized by a relatively low complexity of modulation and demodulation. Thus, it is beneficial to use it with a direct link to reduce power consumption in the end device. Another advantage of using PAM for a direct link is that it may already be used by other data interfaces in the end device, and thus digital processing components can be shared between the optical link and other data interfaces in the end device. Also, a further advantage in this scenario is that the optical link may be used as a replacement for other data interfaces towards other end devices. The other data interfaces may be by USB or HDMI.

[0032] In a further example, the second modulation scheme may be by on-off-keying (OOK) modulation. OOK is the simplest form of amplitude-shift keying (ASK). For many low-power applications, OOK is advantageous in its low complexity.

[0033] Advantageously, the beam angle of the first optical transceiver is at least 30 degrees.

[0034] The first optical transceiver is intended to establish a reliable optical link with an optical access point in a relatively large FoV. Due to the relatively large beam angle, the connection between the device and the optical access point can be maintained even when the device is moving around in a relatively large area. The beam angle of the first optical transceiver is at least 30 degrees, preferably 35 degrees or more.

[0035] Preferably, the beam angle of the second optical transceiver (220) is at most 20 degrees.

[0036] For the second type of optical wireless link, it is important to reduce the power consumption and form factor in view of the physical constraints imposed by the end devices. Thus, a narrow beam link is the preferred design choice. The second optical transceiver has a beam angle of at most 20 degrees, preferably 15 degrees or less.

[0037] In a preferred setup, the first type of optical wireless link supports point-to-multipoint communication.

[0038] Point-to-multipoint communication (P2MP) is a type of one-to-many connection that provides multiple paths from a single location to multiple locations. Thus, it is desirable for an optical access point to support P2MP, which allows the optical access point to connect to multiple end devices / users simultaneously. This has proven to be an efficient way of utilizing the communication capacity of an optical cell.

[0039] In another preferred setup, the second type of optical wireless link is a point-to-point link.

[0040] To avoid the complexities involved in managing P2MP, the second type of optical wireless link preferably opts for point-to-point (P2P) communication and serves as a dedicated connection between two end devices or between an end device and a device, thereby avoiding the coordination required for P2MP communication.

[0041] In a preferred setup, the apparatus includes a third optical transceiver configured to communicate with another end device of the one or more end devices over an optical wireless link of the second type.

[0042] The device plays the role of a bridge device or a hub device in such a hybrid system. The device may include two or more optical transceivers for a second type of optical wireless link, such as a third optical transceiver. When the first functionality is enabled in the operating mode, the device may be used to act as a bridge device between an OWC access point and one or more end devices, such as the first end device and / or other end devices. When the second functionality is enabled in the operating mode, the device may be used to relay data between the first end device and other end devices.

[0043] Depending on the application scenario, the apparatus may further include an additional optical transceiver for a second type of optical wireless link to accommodate high density deployment of end devices.

[0044] In one example, when the first functionality is enabled, the hub component is further configured to split data from a packet received by the first optical transceiver, provide the first portion thereof to the second optical transceiver, and provide the second portion thereof to the third optical transceiver.

[0045] To support various applications, individual sessions may have different data rate requirements. In some cases, the differences may be significant. For example, the data rate required to send a text message and the data rate required to stream high definition video differ by several orders of magnitude. When an OWC access point is connected to two or more end devices via an apparatus, it is efficient to bundle communication data addressed to different end devices into the same packet to reduce communication overhead, considering that some applications may require only very low throughput. In such a scenario, the hub component is further configured to rearrange information carried in one or more data packets received from the OWC access point before providing related information addressed to different end devices to the second and third optical transceivers and / or further optical transceivers.

[0046] Beneficially, the second optical transceiver and the third optical transceiver have a shared common part, the shared common part being not an optical front end.

[0047] Because the second optical transceiver and the third optical transceiver are configured to communicate over the same second type of optical wireless link, one option is to have the second optical transceiver and the third optical transceiver share common components to reduce size, hardware costs, and power consumption compared to another option of deploying two identical optical transceivers.

[0048] The optical transceiver includes multiple building blocks, such as digital modulator and demodulator components (also called modem components), analog front end (AFE), optical front end, etc. The common part can be either the modulator and demodulator components or the AFE, but not necessarily the optical front end, because the second optical transceiver and the third optical transceiver should have their own dedicated optical front ends oriented in different directions.

[0049] Advantageously, the second optical transceiver and the third optical transceiver are oriented in different fields of view (FOV) without overlap, where overlap is envisaged to represent either the area covered by the respective transceivers or, alternatively, the solid angle served by the transceivers.

[0050] The device includes one or more optical transceivers for a second type of optical wireless link, such as a second optical transceiver, a third optical transceiver, and a further optical transceiver. The one or more optical transceivers are directed to different FoVs without overlap. There are several advantages. First, such an arrangement can help to reduce mutual interference between multiple second type optical wireless links. Second, considering the relatively narrow beam angles of the individual optical transceivers, it also helps to increase the likelihood of establishing a connection between the device and an end device and / or establishing multiple connections between the device and multiple end devices simultaneously.

[0051] Different FoVs may be achieved by emission of optical signals at different heights relative to the same reference plane or different orientations at the same or different altitudes. As a reference plane the ground floor or a table surface may be considered.

[0052] In another example, when the second functionality is enabled, the second optical transceiver and the third optical transceiver are further configured to pass through a received data packet, destined for another end device of the one or more end devices, to the respective optical transceiver without demodulating or decoding a payload portion of the packet.

[0053] When operating as a relay node according to the second functionality, the apparatus may simply perform an amplify-and-forward (AF) relay operation, not demodulating or decoding the payload portion of the packet received from the end device, considering that the same modulation and coding scheme is used by the two end devices. This also reduces the latency introduced by the intermediate relay operation. Upon receiving the data packet, the second optical transceiver and / or the third optical transceiver checks the packet header to determine whether the packet is destined for another end device. If so, the packet is passed to the hub component without further demodulating and decoding the information carried in the payload portion. The hub component then provides the packet to the corresponding optical transceiver, which is directed to the intended destination end device.

[0054] According to a second aspect of the present invention there is provided an optical wireless communication system, the optical wireless communication (OWC) system comprising an apparatus according to the present invention and an OWC access point comprising a communication interface to a further network and an optical transceiver configured to communicate with the apparatus by a first type of optical wireless link using a first modulation scheme.

[0055] The optical wireless communications system further includes one or more end devices, each including another optical transceiver configured to communicate with a remote device over a second type of optical wireless link using a second modulation scheme, where the remote device may be either the apparatus or another end device of the one or more end devices.

[0056] According to a third aspect of the present invention, there is provided a method for exchanging data of an apparatus in an optical wireless communication (OWC) system, the method comprising: the apparatus operating in a first mode enabling a first functionality by acting as a bridge device between an OWC access point and a first end device of one or more end devices, or in a second mode enabling a second functionality by relaying data between the first end device and a second end device of the one or more end devices, the method further comprising the apparatus communicating with the OWC access point by a first optical transceiver over a first type of optical wireless link using a first modulation scheme, communicating with the first end device by a second optical transceiver over a second type of optical wireless link using a second modulation scheme, selecting an operation mode from a set including the first mode, the second mode, and another mode in which both the first functionality and the second functionality are enabled, and connecting using the first and / or second optical transceivers according to the selected operation mode, the first optical transceiver having a wider beam angle compared to the second optical transceiver.

[0057] The present invention may further be embodied in a computing program comprising code means which, when said program is executed by an apparatus comprising a processing means, causes the processing means to perform the apparatus methods disclosed in the present invention. [Brief description of the drawings]

[0058] In the drawings, like reference characters generally refer to the same parts throughout the different views and the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. [Figure 1] 1 illustrates a peer-to-peer optical wireless link between end devices. [Diagram 2]1 illustrates that the apparatus acts as a bridge device for an end device or as a relay device between two end devices in an OWC network. [Diagram 3] 13 shows a top view of an apparatus connecting to one or more end devices via a second type of optical wireless link. [Figure 4] 2D diagram of an apparatus capable of simultaneously establishing one or more second type optical wireless links without overlapping. [Diagram 5] 1 shows a schematic of the basic components of the device. [Figure 6] 2 shows a schematic diagram of another example of basic components of a device; [Figure 7] 1 illustrates an optical wireless communication system. [Figure 8] 1 shows a flow chart of a method of the apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] FIG. 1 illustrates a peer-to-peer optical wireless link between end devices. The end devices may be smartphones, tablets, laptops, remote controllers, televisions, or other display devices. The end devices include optical transceivers that engage in a second type of optical wireless link, characterized by a relatively narrow beam, such as having a beam angle not exceeding 20 degrees. The narrow dedicated beam has the advantage of providing higher energy efficiency in data transmission. For example, to achieve the same data rate over a certain communication distance, a narrow beam optical link requires less transmission power compared to a wide beam.

[0060] It is desirable to fully integrate the optical transceiver into the end device, which can be very attractive to smartphone or tablet users. However, due to the small form factor of the end device itself, it is more challenging to integrate both the electronics and optics of the optical transceiver into such a small end device, considering constraints such as physical dimensions, power consumption, heat dissipation, scheduling complexity, etc. Considering all these constraints, typically only limited transmission power can be used for OWC by small end devices such as smartphones, tablets, or remote controllers, which results in short to medium range applications with limited beam angle / coverage. It is preferable to use a modulation scheme without DC bias to further improve power efficiency. PAM and OOK are good candidates for such power-efficient links.

[0061] The use cases are mainly point-to-point (P2P) scenarios, such as device-to-device communication (smartphone to smartphone, smartphone to tablet, smartphone to laptop, smartphone to TV, tablet to tablet, etc.). Compared with wired connections, wireless optical links are advantageous. In this case, users do not need to worry about additional cables and matching interfaces between end devices and cables. There are also non-optical wireless P2P communication technologies, such as RF-based technologies. However, due to the propagation characteristics of RF communication, it can be quite complicated at the protocol level to build the link to allow a certain protection of data, such as in the case of Wi-Fi Direct. Another P2P communication technology often used for smartphones is based on Bluetooth technology, which has a more limited data rate. Therefore, the disclosed narrow-beam P2P optical link has the advantages of higher data rate, good security, and low complexity.

[0062] As mentioned above, the second type of optical wireless link, which is tailored for integration into small end devices, is no longer compatible with the traditional optical wireless link in an OWC network or the first type of optical wireless link. Meanwhile, from the application point of view, it may be a significant improvement that small end devices can also access an OWC network and fully enjoy the benefits brought by OWC. In view of this, an apparatus is disclosed in the present invention.

[0063] FIG. 2 illustrates a user scenario of an apparatus 200 that may act as a bridge device for an end device 300 or as a relay device between two end devices 300 in an OWC network.

[0064] The infrastructure-based OWC network includes at least one OWC access point 400. There may be one or more endpoints within the coverage of the OWC access point 400. If there are more than one active endpoints within the optical cell, the OWC access point 400 can establish multiple optical links simultaneously with the two or more active endpoints in point-to-multipoint communication (P2MP). There may be other endpoint devices active within the same area with the device 200. The other endpoint devices should also include an optical transceiver supporting a first type of optical wireless link 450 to access the OWC network. As shown in the figure, the other endpoint devices may be laptops, PCs, or other electronic devices that include or are coupled to an optical transceiver supporting the first type of optical wireless link 450.

[0065] The first type of optical wireless link 450 between the device 200 and the OWC access point 400 is illustrated by two large, respectively shaded triangles. Similarly, the second type of optical wireless link 350 between the device 200 and the end device 300a, 300b or between two end devices 300c, 300d is illustrated by a smaller, shaded triangle. It should be noted that the shape and size of the triangles used in the figures are illustrative of the relative size and shape of the optical beams. Typically, the beam angle of the first type of optical wireless link 450 is at least 30 degrees (preferably 35 degrees or more), and the beam angle of the second type of optical wireless link 350 is not more than 20 degrees (preferably 15 degrees or less). Moreover, the communication distance supported by the first type of optical wireless link 450 is longer than that of the second type of optical wireless link 350. The power to drive the optical front-end for the second type of optical wireless link 350 is typically 500 mW or less, preferably 250 mW or less, taking into account the constraints of the end device in terms of physical size, power consumption, and heat dissipation. Another consideration that allows for a relatively low radiated power by the optical transmitter for the second type of optical wireless link 350 is for eye safety reasons, considering that the end device, such as a smartphone, may be held by a user when enabling the second type of optical wireless link 350. Therefore, the communication range of the second type of optical wireless link 350 is typically up to 3 m, while the communication range of the first type of optical wireless link 450 is typically more than 3 m to provide sufficient coverage.

[0066] As shown in the example of FIG. 2, the device 200 may operate in a first mode having a first functionality for bridging the OWC access point 400 and the first end device 300a, 300b. The device may also operate in a second mode having a second functionality for relaying data between the first end device 300a and another end device 300b. The first functionality and the second functionality are not exclusive and can be enabled simultaneously. In other words, the operation mode of the device 200 may be the first mode, the second mode, or another mode in which both the first functionality and the second functionality are enabled.

[0067] The two end devices 300c, 300d are within direct communication range and in this case directly establish a P2P link 350. If the two end devices 300c, 300d move apart or there is an obstacle between them that blocks the line of sight, they may rely on device 200 to maintain a connection via an relay at device 200.

[0068] 3 shows a top view of an apparatus connecting to one or more end devices 300a, 300b, 300c, 300d via a second type of optical wireless link 350. The apparatus may include one or more optical transceivers supporting the second type of optical wireless link 350, each directed to a different end device 300a, 300b, 300c, 300d. The one or more end devices 300a, 300b, 300c, 300d are within a maximum distance D from the apparatus 200. The maximum distance D is the same as the maximum communication distance between two end devices for establishing a direct optical link.

[0069] The information communicated over the second type of optical wireless link 350 may be obtained by the apparatus 200, from the OWC access point 400, or from another end device, depending on the mode of operation.

[0070] When the first functionality is enabled, considering that the first type of optical wireless link 450 is typically a higher data rate compared to the second type of optical wireless link 350, data to be transmitted to different end devices may be bundled into the same data packet transmitted from the OWC access point 400. The device 200 then recompiles the data and provides the corresponding parts of the packet to the respective destination end devices. The same applies to the uplink situation. The device 200 may bundle the data received from different end devices and transmit them to the OWC access point 400 in the same packet. Such a conversion would not add extra overhead to the device. Since different modulation schemes are used by the first type of optical wireless link 450 and the second type of optical wireless link 350, digital processing to facilitate the conversion between the different modulation schemes is inevitable.

[0071] When the apparatus acts as a relay device between two end devices according to the second functionality, a data packet received from the second type optical wireless link 350 may be passed through by the apparatus for transmission via another second type optical wireless link 350 without demodulating or decoding the payload portion of the packet. In this way, the operation in the apparatus is simplified and the latency caused by relaying is also reduced.

[0072] 4 shows a 2D view of an apparatus capable of simultaneously establishing one or more second type optical wireless links without overlap. To avoid mutual interference between one or more optical transceivers implementing the second type optical wireless links 350, the FoVs of the one or more optical transceivers have no overlap. Different FoVs may be achieved by arranging one or more optical transceivers to emit optical signals at different heights relative to the same reference plane or different orientations at the same or different altitudes. The reference plane may be a ground floor or a table surface.

[0073] Thanks to the relatively narrow beam angle of the second type wireless optical link, the apparatus may simultaneously deploy and enable multiple second type optical wireless links directed to different end devices to meet demanding application scenarios.

[0074] Since the device can simultaneously maintain one or more second type optical wireless links, it is also optional for one end device to send the same packet to two or more destination end devices through the relay of the device. Thus, the P2P link of the second type optical wireless link may be extended to an equivalent point-to-multipoint connection through the device. This is very convenient and efficient when a user wants to share the same information with multiple people at the same time.

[0075] Fig. 5 shows a schematic of the basic components of the apparatus 200. The apparatus 200 includes at least a first optical transceiver 210, a second optical transceiver 220, and a hub component 240. The first optical transceiver 210 is configured to communicate with the OWC access point 400 by a first type of optical wireless link 450 using a first modulation scheme. The first modulation scheme is preferably by OFDM or OFDMA. In OWCs, unipolar OFDM modulation techniques are typically adopted, such as ACO-OFDM, DCO-OFDM, ADO-OFDM and / or flipped OFDM. The second optical transceiver 220 is configured to communicate with the first end device 300a, 300b, 300c, 300d by a second type of optical wireless link 350 using a second modulation scheme. Preferably, the second modulation scheme uses PAM or OOK, which are low complexity and suitable for the low power consumption requirements of the second type of optical wireless link 350. The hub component 240 is configured to select an operation mode from a set including the first mode, the second mode, and another mode in which both the first and second functionality are enabled, and to connect using the first optical transceiver 210 and / or the second optical transceiver 220 depending on the selected operation mode.

[0076] As mentioned above, the apparatus 200 may be configured to communicate with multiple end devices simultaneously. Thus, as shown generally in FIG. 6, the apparatus 200 may include two or more optical transceivers 220, 230 for a second type of optical wireless link 350.

[0077] For ease of installation, it may be desirable for the device to be charged wirelessly, without requiring a power cable to power the device. Laser charging and RF charging are candidate solutions for wireless charging. Thus, the device may be dynamically deployed depending on the distribution of end devices, such as being placed on a table or in the middle of a living room.

[0078] 7 shows an optical wireless communication system 100. The optical wireless communication system 100 includes at least the device 200 according to the invention and an OWC access point 400. As an example, the OWC access point 400 includes at least a communication interface 410 to a further network 415 and an optical transceiver 420 configured to communicate with the device 200 by a first type of optical wireless link 450 using a first modulation scheme. The communication interface may be a wired connection such as Ethernet, or a wireless connection based on radio frequency (RF) or millimeter wave. The further network 415 may be an IP network or a backbone network.

[0079] 8 shows a flow chart of a method 500, which may be performed using the apparatus 200 as described above. The method 500 includes, in step S501, the apparatus 200 operating in a first mode to enable a first functionality by acting as a bridge device between the OWC access point 400 and a first end device of the one or more end devices 300a, 300b, 300c, 300d, or in a second mode to enable a second functionality by relaying data between the first end device and a second end device of the one or more end devices 300a, 300b, 300c, 300d. The method 500 further includes the apparatus 200 communicating with the OWC access point 400 via the first optical transceiver 210 via a first type of optical wireless link 450 using a first modulation scheme in step S502, communicating with the first end device via the second optical transceiver 220 via a second type of optical wireless link 350 using a second modulation scheme in step S503, selecting an operation mode from a set including a first mode, a second mode, and another mode in which both the first functionality and the second functionality are enabled in step S504, and connecting using the first and / or second optical transceivers depending on the selected operation mode in step S505, wherein the first optical transceiver 210 has a wider beam angle compared to the second optical transceiver 220.

[0080] The method according to the invention may be implemented in a computer as a computer implemented method, or in dedicated hardware, or in a combination of both.

[0081] The executable code for the method according to the invention may be stored on a computer / machine readable storage means. Examples of computer / machine readable storage means include non-volatile memory devices, optical storage media / devices, solid state media, integrated circuits, servers etc. Preferably, the computer program product comprises non-transitory program code means stored on a computer readable medium for performing the method according to the invention when said program product is run on a computer.

[0082] Methods, systems and computer readable media (transitory and non-transitory) may be provided for implementing selected aspects of the above-described embodiments.

[0083] The terms "program" or "computer program" are used herein in a general sense to refer to any type of computer code (e.g., software or microcode) that can be employed to program one or more processors or controllers.

[0084] The term "network," as used herein, refers to any interconnection of two or more devices (including controllers or processors) that facilitates the transfer of information (e.g., related to device control, data storage, data exchange, etc.) between any two or more devices and / or between multiple devices coupled to the network.

Claims

1. 1. An apparatus for exchanging data in an optical wireless communication (OWC) system, the apparatus comprising: a first mode enabling a first functionality in which the apparatus acts as a bridge device between an OWC access point and a first end device of the one or more end devices; or a second mode in which the apparatus enables a second functionality of relaying data between the first end device and a second end device of the one or more end devices; configured to operate with The device comprises: a first optical transceiver configured to communicate with the OWC access point over a first type of optical wireless link using a first modulation scheme; a second optical transceiver configured to communicate with the first end device over a second type of optical wireless link using a second modulation scheme; a third optical transceiver configured to communicate with the second end device over the second type of optical wireless link; and selecting an operating mode from a set including the first mode, the second mode, and another mode in which both the first functionality and the second functionality are enabled; and connecting using at least two of the first optical transceiver, the second optical transceiver, and the third optical transceiver according to a selected mode of operation; A hub component configured as follows: Including, An apparatus, wherein the first optical transceiver has a wider beam angle compared to the second optical transceiver or the third optical transceiver.

2. The apparatus of claim 1 , wherein the first optical transceiver supports a higher data rate or a longer communication distance compared to the second optical transceiver.

3. 3. The apparatus of claim 1 or 2, wherein the hub component is configured to determine an operating mode according to at least one of a user input, a predetermined configuration parameter, packets received by the first optical transceiver or the second optical transceiver, detection of the presence of one or more end devices, or input from the first optical transceiver or the second optical transceiver regarding detection of the presence of an OWC access point.

4. 3. The apparatus of claim 1 or 2, wherein the first modulation scheme is by Orthogonal Frequency Division Multiplexing (OFDM).

5. 3. The apparatus of claim 1 or 2, wherein the second modulation scheme is by Pulse Amplitude Modulation (PAM).

6. The apparatus of claim 1 or 2, wherein the beam angle of the first optical transceiver is at least 30 degrees.

7. The apparatus of claim 1 or 2, wherein the beam angle of the second optical transceiver is at most 20 degrees.

8. The apparatus according to claim 1 or 2, wherein the second type of optical wireless link is a point-to-point link.

9. When the first functionality is enabled, the hub component: splitting data from packets received by the first optical transceiver; providing the first portion to the second optical transceiver; and providing the second portion to the third optical transceiver.

3. The apparatus according to claim 1 or 2, configured to:

10. The apparatus of claim 1 or 2, wherein the second optical transceiver and the third optical transceiver have a shared common portion, the shared common portion being not an optical front end.

11. The apparatus of claim 1 or 2, wherein the second optical transceiver and the third optical transceiver are oriented in different non-overlapping fields of view (FOV).

12. 3. The apparatus of claim 1, wherein when the second functionality is enabled, the second optical transceiver and the third optical transceiver are configured to pass through received data packets destined for another end device of the one or more end devices to their respective optical transceivers without demodulating or decoding a payload portion of the packet.

13. 1. An optical wireless communication (OWC) system, comprising: An apparatus according to claim 1 or 2; an OWC access point including a communication interface to a further network and an optical transceiver configured to communicate with said device by a first type of optical wireless link using a first modulation scheme; An optical wireless communication system comprising:

14. 1. A method for data exchange of devices in an optical wireless communication (OWC) system, the method comprising: a first mode that enables a first functionality by acting as a bridge device between the OWC access point and a first end device of the one or more end devices; or a second mode enabling a second functionality by relaying data between the first end device and a second end device of the one or more end devices; Including operating in The method further comprises the steps of: communicating with the OWC access point by a first optical transceiver over a first type of optical wireless link using a first modulation scheme; communicating with the first end device by a second optical transceiver over a second type of optical wireless link using a second modulation scheme; communicating with the second end device via a third optical transceiver over the second type optical wireless link; selecting an operational mode from a set including the first mode, the second mode, and another mode in which both the first functionality and the second functionality are enabled; connecting using at least two of the first optical transceiver, the second optical transceiver, and the third optical transceiver according to a selected mode of operation; Including, The method, wherein the first optical transceiver has a wider beam angle compared to the second optical transceiver.

15. A computing program comprising code means which, when said program is executed by an apparatus including a processing means, causes said processing means of said apparatus to carry out the method according to claim 14.

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