Systems and methods for implementing high-speed wireless file transmission

Abstract

Given the potential high data rate and confidentiality of optical wireless communication, Li-Fi proves to be an attractive technology for enabling high-speed wireless data transmission between remote devices. The present invention relates to various methods, systems, and devices for achieving high-speed file transfer between a user-held device (300) and a remote device (400) via a high-speed Li-Fi link (200). When the user-held device (300) receives a trigger command, a trigger signal is sent to the remote device (400) via another communication link (500) having a wide beam width. The remote device (400) provides a human-perceivable indication of a dedicated reception area after receiving the trigger signal to assist the user in aligning the user-held device (300) for the alignment required to enable the high-speed Li-Fi link (200). After determining that the alignment state permits file transfer, or after the user-held device (300) receives a start transmission command, high-speed file transfer begins.

Description

Technical Field

[0001] The present invention relates to the field of high-speed file transfer via optical wireless networks, such as Li-Fi networks. More particularly, various methods, apparatuses, systems, and computer-readable media related to improvements in establishing high-speed Li-Fi links between a user-held device and a remote device are disclosed herein. Background Art

[0002] To enable an increasing number of electronic devices, such as laptops, tablets, and smartphones, to wirelessly connect to the Internet to browse rich content, wireless communication faces unprecedented requirements for data rate and also link quality, and these requirements keep growing year by year considering the emerging digital revolution related to the Internet of Things (IoT). Radio frequency technologies, such as Wi-Fi, are running out of spectrum to fully support this revolution. At the same time, Li-Fi is attracting increasing attention due to its ability to support higher data rates over a much wider bandwidth in the visible, ultraviolet, and infrared spectra. Other benefits of Li-Fi include data security, and the ability to operate securely in an area without electromagnetic interference. Therefore, Li-Fi is a very promising technology for realizing the next generation of immersive connectivity.

[0003] Visible light communication (VLC) transmits data by intensity modulating a light source, such as a light-emitting diode (LED) and a laser diode (LD), at a speed faster than the persistence of the human eye. VLC combines lighting and data communication in applications such as area lighting, billboards, streetlights, vehicles, and traffic signals. The IEEE 802.15.7 Visible Light Communication Personal Area Network (VPAN) standard maps the expected applications to four topologies: peer-to-peer, star, broadcast, and coordinated. Optical Wireless PAN (OWPAN) is a more general term than VPAN, which also allows invisible light for communication.

[0004] Considering the potentially high data rate and confidentiality brought by Li-Fi or optical wireless communication (OWC), it has proven to be an attractive technology for realizing high-speed wireless data transfer between remote devices.

[0005] US2015201443 A1 relates to methods and systems for establishing an infrared (IR)-triggered radio communication connection between two devices. When aligning the IR ports, IR communication links can be used to exchange IR-triggered messages between the device and / or the access point, where the IR-triggered messages indicate the intention and ability to establish a connection. The IR-triggered messages can trigger device discovery and connection using radio communication technologies.

[0006] US2011033181 A1 relates to visible light communication technology capable of visually identifying transmission speed, alignment status, communication status, or transmission rate. The visible light communication device according to an embodiment of the present invention includes: a light source selection unit that selects at least one light source from a plurality of light sources that generate light having different wavelengths by considering visual information differentiated depending on wavelengths in the visible light band; and a visible light communication unit that performs visible light communication through the at least one selected light source to allow visual information to be identified by a color corresponding to the at least one selected light source. SUMMARY OF THE INVENTION

[0007] In view of the above, the present disclosure is directed to innovative methods, devices, systems, computer programs, and computer-readable media for providing an easy-to-use high-speed wireless file transfer connection between remote devices. More particularly, various computer-readable media (transitory and non-transitory), methods, systems, and devices are provided for enabling high-speed file transfer between a device held by a user and a remote device via a high-speed Li-Fi link.

[0008] According to a first aspect of the present invention, there is provided a system. The system is for enabling high-speed file transfer between a device held by a user and a remote device via a high-speed Li-Fi link. The system includes the device held by the user, which includes a first transmitter, a Li-Fi transmitter, and a first user interface (UI); the remote device includes a second receiver, a second Li-Fi receiver, and a second UI; and wherein the device held by the user is configured to, upon receiving a trigger command via the first UI, send a trigger signal from the first transmitter to the remote device for setting up the high-speed Li-Fi link; and the remote device is configured to, upon receiving the trigger signal by the second receiver, provide a human-perceivable indication of a dedicated receiving area on the remote device via the second UI to assist in adjusting the position and / or orientation of the device held by the user so as to point the Li-Fi transmitter at the dedicated receiving area; provide feedback on the alignment status between the Li-Fi transmitter in the device held by the user and the dedicated receiving area; and the device held by the user is further configured to, when the alignment status provided by the remote device is determined to allow file transfer or upon receiving a start transmission command via the first UI, transfer a file from the Li-Fi transmitter to the second Li-Fi receiver in the remote device via the high-speed Li-Fi link; and wherein the trigger signal sent from the first transmitter is via another link different from the high-speed Li-Fi link, and the another link can be based on at least one of an infrared link, a radio frequency link, and another optical link having a wider beam width than the high-speed Li-Fi link.

[0009] Due to the high bandwidth capacity above the unauthorized optical wavelength, optical communication has become a very attractive technology for broadband wireless communication - such as live streaming and remote file transfer. However, to enable a high-speed optical link between two remote devices, very complex system setups and procedures are usually required, such as adjustable beam divergence control for link acquisition and data transmission. The present invention proposes a system to simplify the interaction between the system and the user, and advantageously establish a high-speed file transfer connection between the device held by the user and the remote device in an easily controllable manner. Note that the device held by the user should be understood as a mobile device or a handheld device, such as a laser pointer, a remote control, a smart phone, a tablet, or a laptop computer, which has hardware supporting optical communication. The remote device can be a remote display device, such as a TV, a projector, a monitor, or an interactive screen. The remote device can also be a storage device, which is deployed to collect, organize, and backup data. The data storage in the remote device can be "permanent" (for a longer period), but it can also be temporary to transfer / relay the data to a (cloud) server.

[0010] When a trigger command from the user arrives via the first UI, the device held by the user sends a trigger signal to the remote device. The trigger signal is sent via a link different from the high-speed Li-Fi link. Since the trigger signal contains very limited information, there is no hard data rate requirement on this link, which is mainly used for the exchange of control signals. In principle, any short-range wireless communication standard should be feasible as long as it has lower directivity compared to the high-speed Li-Fi link. In this way, the trigger signal can be sent to the remote device without any special alignment.

[0011] Note that in order to allow high-speed data transmission within a specific power limit, considering that the distance from the device held by the user to the remote device can reach several meters, the beam width of the narrow high-speed Li-Fi link generally does not exceed 20 degrees. Preferably, the beam width of the narrow high-speed Li-Fi link is kept within 6 degrees. On the other hand, the beam width of the other link is generally at least 30 degrees to cover a large area, and preferably greater than 45 degrees. In this way, the remote device can be easily triggered to provide a human-perceivable indication to gain the user's attention, and thus, further adjustments can be made to the device held by the user to prepare for the high-speed Li-Fi link.

[0012] When there are more than one remote device in a single room, it can be beneficial to make the other link somewhat selective to avoid accidentally mis-triggering another remote device. In this case, the beam width of the other link may be narrower (such as less than 30 degrees), but at least two to three times the beam width of the high-speed Li-Fi link.

[0013] In response to a trigger signal, the remote device provides a human-perceivable indication via the second UI regarding a dedicated receiving area on the remote device. Thus, the user receives an immediate response from the remote device, which helps the user quickly identify how the device at hand and the remote device interact. The user-perceivable indication can be implemented by at least one of the following: illuminating the dedicated receiving area, illuminating a light band surrounding the dedicated receiving area, displaying an arrow pointing to the dedicated receiving area, displaying a description of the relative positioning of the dedicated receiving area on the remote device, a voice message indicating the dedicated receiving area. In another example, the remote device includes a display area, where the second Li-Fi receiver is integrated behind the display. The human-perceivable indication can be provided by directly presenting the dedicated receiving area on the display.

[0014] Considering that the relative size of the dedicated receiving area for Li-Fi signals is typically much smaller compared to the remote device, this human-perceivable indication of the receiving area can be very beneficial for the user to adjust the position or orientation of the device held by the user, especially considering the typical narrow beam of a high-speed Li-Fi link. The Li-Fi transmitter can also send a predefined test signal or virtual data during the test phase of the Li-Fi link, and the remote device is configured to provide feedback regarding the alignment state. The alignment state indicates whether the beam of the Li-Fi transmitter in the device held by the user is fully or partially aligned with the receiving area on the remote device. In one example, the alignment state can be a text or voice message, a binary value, a ratio, or a percentage. The alignment is determined to be sufficient if the transmitter beam is fully aligned with the receiving area, or if the overlapping portion of the transmission beam and the receiving area is higher than a predefined threshold, or higher than a configurable threshold derived from one or more parameters such as the required data rate and the actual link quality conditions. Typically, higher data rates can be supported under better link quality conditions. And thus, given a higher-level system criterion - such as the typical time interval during which the user can stably hold the device held by the user in a fixed position - it takes less time to transmit a specific file via the Li-Fi link.

[0015] Preferably, the trigger signal can also include the identification information of the device held by the user, which enables the remote device to identify each device held by the user from multiple devices attempting to simultaneously establish a high-speed Li-Fi link. The remote device can typically establish one high-speed Li-Fi link with one device at a time, for example, by rejecting a second trigger until the file transfer with the first device is completed. Additionally, the identification information can be employed in a security protocol, etc., so as to only allow trusted devices held by the user to establish a high-speed Li-Fi link, or to provide a device-specific password mechanism for the high-speed Li-Fi link.

[0016] Advantageously, the first transmitter and the second receiver have lower active power consumption than a Li-Fi transmitter and a second Li-Fi receiver, respectively.

[0017] Another link from the first transmitter in the user-held device to the second receiver in the remote device can be used as a wake-up mechanism to wake up the high-performance and high-power-consuming Li-Fi link. In the remote device, the second receiver should monitor the channel to detect potential trigger signals by always staying active or applying a specific duty cycle, while the second Li-Fi receiver can be in a sleep mode most of the time until a valid trigger signal is detected. With lower active power consumption of the first transmitter and the second receiver compared to the Li-Fi transmitter and the second Li-Fi receiver, the average system power consumption is reduced.

[0018] In one embodiment, the feedback from the remote device further includes at least one of the following: an instruction regarding the direction for adjusting the position and / or orientation of the user-held device; link quality information of the high-speed Li-Fi link; and a suggestion for further improving the link quality; and the feedback can be provided directly via the second UI or via a feedback signal that is sent to the user-held device via another link by a second transmitter included in the remote device.

[0019] The feedback from the remote device to the user-held device can contain more information than just the alignment status, such as information to assist the user in an active method. Thus, the system becomes more responsive, and it can help accelerate the link establishment process of the high-speed Li-Fi link.

[0020] Preferably, the remote device is further configured to provide another feedback during or after file transfer; and wherein the another feedback includes at least one of the following: a status that the transfer is in progress, a status that the transfer has been interrupted, a status that the transfer has been completed, link quality information, an acknowledgement of file reception, an acknowledgement of partial reception of a file, and a negative acknowledgement of file reception.

[0021] In addition to the feedback during link establishment, the applicant recognizes that it is beneficial to have another feedback during or after file transfer. The link quality information can be real-time link quality information or average link quality information during file transfer. Such feedback provides the user with a confirmation regarding the ongoing file transfer or the most recent file transfer. It can also help the user identify any link issues during file transfer, such as a sudden link failure due to unconscious hand tremors.

[0022] In one embodiment, the device held by the user is further configured to turn on the Li-Fi transmitter when a trigger command is received via the first UI; and turn off the Li-Fi transmitter after the file transfer to the remote device via the high-speed Li-Fi link is completed, or aborted by the user, or ended due to an interruption.

[0023] In another embodiment, the remote device is further configured to turn on the second Li-Fi receiver when a trigger signal is received; and turn off the second Li-Fi receiver after the file reception from the device held by the user via the high-speed Li-Fi link is completed, or aborted by the user, or ended due to an interruption, or after a predefined timer expires.

[0024] Considering the high power consumption of the Li-Fi transmitter in the device held by the user and the second Li-Fi receiver in the remote device, it is preferred to turn on the Li-Fi transmitter and the second Li-Fi receiver according to the demand and then turn them off when the arranged activity is completed.

[0025] Advantageously, the device held by the user is further configured to highlight the projected transmission area by emitting a visible light beam to further assist in adjusting the position and / or orientation of the device held by the user, so as to direct the Li-Fi transmitter to the dedicated reception area on the remote device.

[0026] Considering the high directivity of the high-speed Li-Fi beam and the distance between the device held by the user and the remote device, it is beneficial to use a visible light beam to highlight the projected transmission area. Therefore, it is more straightforward for the user to align the emitted beam with the dedicated reception area on the remote device.

[0027] A typical human eye will respond to wavelengths from approximately 380 nm to 740 nm, which also corresponds to the visible spectral band around 430 - 770 THz. Li-Fi is a broader term that encompasses visible light, as well as the ultraviolet and infrared spectra. This visible light beam can be enabled only during the link establishment phase to assist the user, and the Li-Fi transmitter can switch to other spectra with more bandwidth for high-speed file transfer. In one example, the visible light beam can be arranged by having the Li-Fi transmitter emit in the visible spectral band during the link establishment phase. In another example, the visible light beam can be arranged by activating a second beam along with the high-speed Li-Fi beam in the visible spectral band, where the second beam is aligned with the high-speed Li-Fi beam and has a similar beam width. To further assist in the alignment of the high-speed Li-Fi beam, this second (low-cost) beam may also be used to convey additional information by modulating the second beam at a low bit rate. Of course, modulation of the second beam is not necessary. In additional examples, the visible light beam is used as the high-speed Li-Fi beam during both the link establishment phase and the data transfer phase. In both phases, the visible light beam is projected with the same beam width, but can be modulated at different bit rates. For example, during the link establishment phase, the visible light beam can be modulated at a low bit rate to save power, while during the data transfer phase, the beam is modulated at a much higher bit rate to transfer large files in a short period of time.

[0028] In another embodiment, the device held by the user further includes a Li-Fi receiver, the remote device further includes a second Li-Fi transmitter, and the device held by the user is configured to, when receiving a second trigger command via the first UI, send a second trigger signal from the first transmitter to the remote device for setting up a high-speed Li-Fi link; and the remote device is configured to, when the second trigger signal is received by the second receiver, provide a human-perceivable indication of a dedicated transmission area on the remote device via the second UI to assist in adjusting the position and / or orientation of the device held by the user so as to point the Li-Fi receiver towards the dedicated transmission area; and the device held by the user is further configured to evaluate the alignment state between the Li-Fi receiver and the dedicated transmission area; when the alignment state is determined to allow file transfer, or when a start reception command is received via the first UI, send a third trigger signal from the first transmitter to the remote device for initiating the high-speed Li-Fi link; and the remote device is further configured to transfer a file from the second Li-Fi transmitter to the Li-Fi receiver via the high-speed Li-Fi link when the third trigger signal is received.

[0029] Advantageously, it is disclosed that Li-Fi links can be established in opposite directions to enable file transfer from a remote device to a user-held device. This can occur when user A first shares an album with holiday photos to a remote projector, and then another user B (such as a friend of A) also wants to obtain a copy of the album while he browses the album display via the projector.

[0030] Considering that it is the user who actively enables the opposite link, the establishment of the opposite link is triggered by a second trigger command via the first UI. And then the remote device provides a human-perceivable indication of the dedicated transfer area. The user-held device is also configured to evaluate the alignment state and make a judgment on whether the alignment state is sufficient to allow file transfer. Then, the user-held device sends a third trigger signal to request the remote device to start file transfer.

[0031] In a second aspect of the present invention, a user-held device is provided. The user-held device is used to achieve high-speed file transfer to a remote device via a high-speed Li-Fi link. The user-held device includes a first user interface (UI) configured to receive a trigger command; a first transmitter configured to send a trigger signal to the remote device when the trigger command is received, for setting up the high-speed Li-Fi link; a Li-Fi transmitter configured to transmit a file to a second Li-Fi receiver in the remote device via the high-speed Li-Fi link when the alignment state provided by the remote device is determined to allow file transfer, or when a start transmission command is received via the first UI; and wherein the trigger signal sent from the first transmitter is via another link different from the high-speed Li-Fi link, and the other link can be based on at least one of an infrared link, a radio frequency link, and another optical link having a wider beam width than the high-speed Li-Fi link.

[0032] In one example, the user-held device further includes a memory for storing the file to be transmitted. In another example, the file is not stored locally, but is downloaded at runtime via another air interface - such as BLE, Zigbee, WiFi, or a 3G / 4G / 5G cellular network. Considering the maximum data rate supported by other air interfaces, the time required to download a large file such as a movie can be quite long, which can result in a poor user experience. Possibly a large file is transferred in chunks over another air interface. Each time a chunk of the file is downloaded on the user-held device, the user receives a notification that the chunk is ready for transmission. The size of the chunk can be determined by the actual data rate supported on the other air interface, the total size of the file, or the segmentation of the file itself (such as the part of a movie between two advertisements).

[0033] In another embodiment, the device held by the user comprises: a first receiver configured to receive feedback on an alignment state from a remote device via another link; and a controller configured to determine whether the alignment state permits file transfer.

[0034] Advantageously, the device held by the user receives feedback on the alignment state from the remote device via another link and, thus, if the alignment state is sufficient to permit file transfer, a determination can be made automatically by the controller in the device held by the user. In this way, the system is more spontaneous and reduces user involvement. Generally, this also indicates that a high-speed Li-Fi link can be established more quickly and conveniently.

[0035] In another example, actual file transfer over the high-speed Li-Fi link may only commence when both conditions are met, such as when the feedback on the alignment state received via another link is determined to be sufficient and a start send or start receive command is received via the first UI.

[0036] In a third aspect of the invention, there is provided a remote device. The remote device is adapted to receive high-speed files from a device held by a user via a high-speed Li-Fi link. The remote device comprises: a second receiver configured to receive a trigger signal from the device held by the user for setting up the high-speed Li-Fi link; a second user interface (UI) configured to provide a human-perceivable indication of a dedicated receiving area on the remote device upon receipt of the trigger signal; a second Li-Fi receiver configured to receive files from a Li-Fi transmitter in the device held by the user via the high-speed Li-Fi link; and wherein the remote device is further configured to provide feedback on an alignment state between the Li-Fi transmitter comprised in the device held by the user and the dedicated receiving area; and wherein the trigger signal received by the second receiver is via another link different from the high-speed Li-Fi link, which another link may be based on at least one of an infrared link, a radio frequency link, and another optical link having a wider beam width than the high-speed Li-Fi link.

[0037] Preferably, the remote device further comprises a second transmitter; and wherein the second transmitter is configured to send feedback on the alignment state to the device held by the user via another link.

[0038] In another example, feedback on the alignment state is provided via the second UI in the remote device. Such human-perceivable feedback via the second UI may trigger the user to provide a start send command to the device held by the user via the first UI.

[0039] Advantageously, another feedback from the remote device can be provided in a similar manner, either via a second UI of the remote device or by sending another feedback directly to the user-held device via another link. The another feedback can be provided during or after the high-speed file transfer and can include at least one of the following: the status that the transfer is in progress, the status that the transfer has been interrupted, the status that the transfer has been completed, link quality information, confirmation of file reception, confirmation of partial reception of the file, and negative confirmation of file reception.

[0040] Another aspect of the invention is a method for a user-held device to implement high-speed file transfer to a remote device via a high-speed Li-Fi link. The method includes receiving a trigger command via a first user interface (UI); upon receiving the trigger command, sending a trigger signal from a first transmitter to the remote device for setting up the high-speed Li-Fi link; when the alignment status provided by the remote device is determined to allow file transfer or when a start transmission command is received via the first UI, transferring the file from a Li-Fi transmitter to a second Li-Fi receiver in the remote device via the high-speed Li-Fi link, and wherein the trigger signal sent from the first transmitter is via another link different from the high-speed Li-Fi link, and the another link can be based on at least one of an infrared link, a radio frequency link, and another optical link having a beam width wider than that of the high-speed Li-Fi link.

[0041] Another aspect of the invention is a method for a remote device to adapt to high-speed file reception from a user-held device via a high-speed Li-Fi link. The method includes receiving a trigger signal from the user-held device by a second receiver for setting up the high-speed Li-Fi link; upon receiving the trigger signal, providing a human-perceivable indication regarding a dedicated reception area on the remote device via a second user interface (UI); providing feedback regarding the alignment status between a Li-Fi transmitter included in the user-held device and the dedicated reception area; receiving the file from the Li-Fi transmitter by the second Li-Fi receiver via the high-speed Li-Fi link; and wherein the trigger signal received by the second receiver is via another link different from the high-speed Li-Fi link, and the another link can be based on at least one of an infrared link, a radio frequency link, and another optical link having a beam width wider than that of the high-speed Li-Fi link.

[0042] The invention can also be embodied in a computer program including code means which, when executed by a computer, cause the computer to implement the methods of the user-held device and the remote device. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In the drawings, like reference numerals occur throughout the different views Figure 1Generally refer to the same parts. In addition, the accompanying drawings are not necessarily to scale, and instead generally focus on illustrating the principles of the present invention.

[0044] Figure 1 Illustrates a system for enabling high-speed file transfer between a user-held device and a remote device via a high-speed Li-Fi link;

[0045] Figure 2 Illustrates the setup of a user-held device;

[0046] Figure 3 Illustrates the setup of a remote device;

[0047] Figure 4 Shows a flowchart of a method implemented by a user-held device;

[0048] Figure 5 Shows a flowchart of a method implemented by a remote device. Detailed Description

[0049] Now will be based on as Figure 1 shown to describe various embodiments of the present invention. System 100 is illustrated to enable high-speed file transfer between a user-held device 300 and a remote device 400 via a high-speed Li-Fi link 200. The target speed of the data link is to transfer large files within a few seconds or even less time, such as transferring a gigabyte (GB) file within one second. To support such a high data transfer speed, considering certain power limitations imposed on the system, the user-held device typically employs a narrow beam rather than a wide beam. In addition, due to the small projected area, the narrow beam also improves security and reduces potential interference with other Li-Fi communication links. And thus, it also allows the user to selectively establish a link with the intended remote device.

[0050] Considering that high-speed Li-Fi links typically have a narrow beam width, enabling a high-speed optical link between two remote devices may require a rather complex system setup and process, such as adjustable beam divergence control for link acquisition and data transfer. Therefore, dedicated controllable beam divergence devices and adjustable lenses may be required to shape and / or direct the beam to achieve a specific link quality for data communication. Such devices can be quite bulky for a user-held device, which also results in additional cost for the system.

[0051] The present invention proposes a system to simplify the interaction between the system and the user, and advantageously establish a high-speed file transfer connection between a device held by the user and a remote device in an easily controllable manner. For illustrative purposes, example devices are shown in the figures. In this example, a smart phone is used as the device held by the user, and a TV is used as the remote device. These examples should not be construed as limiting the scope of the present invention. The device held by the user can also be a laser pointer, a remote control, a tablet computer, or a laptop computer, which has hardware support for optical communication. The remote device can be a remote display device or a remote storage device. A trigger signal is sent via another link 500, which can be an infrared link, a radio frequency link, and another optical link with a wider beam width compared to the high-speed Li-Fi link 200. The radio frequency link can be based on BLE, Zigbee, WiFi, or 3G / 4G / 5G cellular standards. Considering the typical propagation characteristics or antenna patterns of the other link, no special alignment is required to establish the other link. And thus the other link is used as the communication medium for signaling exchange to establish a highly directional Li-Fi link.

[0052] Although the main use case is for the device held by the user to transfer files to a remote display device or storage device, it is also possible to establish a Li-Fi link in the opposite direction so that files can be transferred from the remote device to the device held by the user, such as allowing another user to retrieve files from the remote device.

[0053] Figure 2 The setup of the device 300 held by the user is illustrated. The blocks with solid lines 310, 320, 330 are the most basic building blocks for implementing the present invention. The first UI 310 is mainly deployed to receive user commands and potentially provide status / link feedback to the user. Via the first UI 310, the user can provide different commands, such as a trigger command to request the establishment of a link, a start transmission command to request the start of actual data transmission. Potential commands can be:

[0054] · Trigger the Li-Fi link

[0055] · Turn on / off the transmitter

[0056] · Turn on / off the Li-Fi transmitter

[0057] · Start transmission of the Li-Fi link

[0058] · Stop transmission of the Li-Fi link

[0059] · Check the link quality.

[0060] The first transmitter 320 is deployed to enable another link and provide a low-power communication channel for signaling exchange between the user-held device and the remote device. The Li-Fi transmitter 330 is deployed to enable a high-speed Li-Fi link.

[0061] Optionally, the user-held device 300 may also include a Li-Fi receiver 340 to enable the reverse link to receive files, data packets, data frames, or control signaling from the remote device. The user-held device 300 may also include a second receiver 350 and a controller 360. The second receiver 350 is used to enable another link in the reverse direction. Thus, feedback regarding the alignment state from the remote device can be received by the second receiver 350 in the user-held device via another link 500. The controller 360 can determine whether the alignment state is sufficient to allow file transfer. Then, if the controller determines that the alignment state is sufficient, the high-speed Li-Fi link can be immediately activated. The advantage is that less user participation is required, and the entire process is further shortened. Considering that this can help relax the requirement for the time interval during which the user must stably hold the user-held device in a fixed position to maintain beam alignment, this can be particularly beneficial. Alternatively, before starting file transfer, the alignment state can be used as an additional condition for receiving a start command via the first UI.

[0062] Figure 3 The setup of the remote device is illustrated. The blocks with solid lines 410, 420, 430 are the most basic building blocks in the remote device 400. The second UI 410 is used to provide a human-perceivable indication of a dedicated reception area, or potentially a dedicated transmission area for the reverse link. Considering that the relative size of the dedicated reception or transmission area for Li-Fi signals is usually much smaller compared to the remote device, such a perceivable indication of the reception or transmission area can be very beneficial for the user to adjust the position or orientation of the user-held device, especially considering the high directivity of the high-speed Li-Fi link. Potentially, the second UI is also used to provide feedback to the user regarding the alignment state, or provide other feedback, such as proactive feedback regarding accelerating link establishment or improving link quality. Other feedback can be instructions regarding the direction of adjusting the position and / or orientation of the user-held device; link quality information of the high-speed Li-Fi link; and suggestions for further improving link quality; and the feedback can be provided directly via the second UI or via a feedback signal. Thus, the system becomes more responsive, and it can also help accelerate the link establishment process of the high-speed Li-Fi link. The second receiver 420 is deployed such that another link 500 can receive a trigger signal from the user-held device. The Li-Fi receiver 430 is deployed to enable a high-speed Li-Fi link.

[0063] User-perceivable indications provide the user with an immediate response from a remote device, which helps the user quickly identify the manner of interaction between the device at hand and the remote device. And thus, the user can more efficiently adjust the position and / or orientation of the device held by the user. User-perceivable indications can be implemented in different ways, such as by illuminating a dedicated receiving area, illuminating a light band surrounding the dedicated receiving area, displaying an arrow pointing to the dedicated receiving area, displaying a description of the relative positioning of the dedicated receiving area on the remote device, a voice or text message indicating the dedicated receiving area. In one example, a specific form of the illuminated area can indicate the target point - to which the user should direct the beam - or the central position of the actually received beam. In another example, the remote device includes a display area, where a second Li-Fi receiver is integrated behind the display. A human-perceivable indication can be provided by presenting the dedicated receiving area directly on the display. Optionally, the remote device also includes a second transmitter 450 for sending the above feedback directly to the device held by the user and allowing autonomous control of file transfer by a controller 360 included in the device held by the user, or serving as an additional requirement for an actual file transfer after a start transmission command is received via the first UI. The remote device can also include a second Li-Fi transmitter to enable a reverse high-speed Li-Fi link to send files to the device held by the user.

[0064] Figure 4 A flowchart of a method 600 implemented by a device 300 held by a user is shown. In step S601, a trigger command for establishing a high-speed Li-Fi link 200 is received via a first UI 310. In step S602, upon receiving the trigger command, a trigger signal is sent to a remote device 400 via a first transmitter 320. And then depending on whether the alignment state is determined to be sufficient to allow file transfer in step S603 and / or a start transmission command is received in step S604, in step S605, the device held by the user transfers a file to the remote device via the Li-Fi transmitter via the high-speed Li-Fi link. Figure 4 An example is shown where two conditions - a sufficient alignment state and the receipt of a start transmission command - are used as alternatives. It is also possible to use the two conditions in combination, and when both conditions are met, an actual file transfer will occur.

[0065] Figure 5A flowchart of method 700 implemented by remote device 400 is shown. In step S701, the remote device receives a trigger signal from the user-held device 300 via the second receiver 420 for setting up the high-speed Li-Fi link 200. In response to the trigger signal, in step S702, the remote device provides a human-perceivable indication regarding a dedicated reception area on the remote device 400 via the second user interface 410. Further, in step S703, the remote device 400 provides feedback regarding the alignment status between the Li-Fi transmitter 330 included in the user-held device 300 and the dedicated reception area. And then, in step S704, the remote device 400 receives a file from the Li-Fi transmitter 330 via the high-speed Li-Fi link 200 through the second Li-Fi receiver 430.

[0066] The method according to the present invention can be implemented on a computer as a computer-implemented method, or in dedicated hardware, or in a combination of both.

[0067] The executable code of the method according to the present invention can be stored on a computer / machine-readable storage device. Examples of computer / machine-readable storage devices include non-volatile memory devices, optical storage media / devices, solid-state media, integrated circuits, servers, etc. Preferably, a computer program product includes non-transitory program code means stored on a computer-readable medium for performing the method according to the present invention when the program product is executed on a computer.

[0068] Methods, systems, and computer-readable media (transitory and non-transitory) can also be provided to implement selected aspects of the embodiments described above.

[0069] The term "controller" is generally used herein to describe various devices related to the operation of, among other functions, one or more user-held devices and / or remote devices. The controller can be implemented in various ways (e.g., such as with dedicated hardware) to perform the various functions discussed herein. "Processor" is an example of a controller that employs one or more microprocessors, which can be programmed using software (e.g., microcode) to perform the various functions discussed herein. The controller can be implemented with or without a processor and can also be implemented as a combination of dedicated hardware for performing some functions and a processor for performing other functions (e.g., one or more programmed microprocessors and associated circuitry). Examples of controller components that can be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0070] In various embodiments, a processor or controller may be associated with one or more storage media (collectively referred to herein as "memory", such as volatile and non-volatile computer memory, such as RAM, PROM, EPROM, and EEPROM, compact discs, optical discs, etc.). In some embodiments, the storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein. The various storage media may be fixed within the processor or controller or may be transportable such that one or more programs stored thereon can be loaded into the processor or controller to implement various aspects of the invention discussed herein. The term "program" or "computer program" is 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.

[0071] As used herein, the term "network" refers to any interconnection of two or more devices (including controllers or processors) that facilitates the conveyance of information between any two or more devices and / or among multiple devices coupled to the network (e.g., for device control, data storage, data exchange, etc.).

[0072] Unless expressly stated to the contrary, as used herein in the specification and in the claims, the indefinite articles "a" and "an" shall be understood to mean "at least one".

[0073] As used herein in the specification and in the claims, "or" shall be understood to have the same meaning as "and / or" defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as inclusive, i.e., including at least one of multiple elements or a list of elements, but also including more than one of multiple elements or a list of elements, and optionally, additional unlisted items. Only terms expressly stated to the contrary, such as "only one of... " or "exactly one of... ", or "consisting of... " when used in the claims, will refer to including exactly one element of a multiple elements or a list of elements. In general, the term "or" as used herein shall be interpreted as indicating exclusive alternatives (i.e., "one or the other, but not both") only when preceded by exclusive terms such as "either", "one of... ", "only one of... ", or "exactly one of... ". "Consisting essentially of... " shall have its ordinary meaning as used in the field of patent law when used in the claims.

[0074] As used herein in the specification and claims, the phrase "at least one" in reference to a list of one or more elements should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each specific element listed within the list of elements, and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than those specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those specifically identified elements.

[0075] It should also be understood that, unless expressly stated to the contrary, in any method claimed herein that includes more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. Further, the reference numerals (if any) that appear in parentheses in the claims are provided only for convenience and should not be construed as in any way limiting the claims.

[0076] In the claims, as well as in the above specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "accommodating," "containing," etc. are to be understood to be open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" should be closed or semi-closed transitional phrases, respectively.

Claims

1. A system (100) for enabling high-speed file transfer between a user-held device (300) and a remote device (400) via a high-speed Li-Fi link (200), the system (100) comprising: - The user-held device (300), including a first transmitter (320), a Li-Fi transmitter (330), and a first user interface UI (310); - The remote device (400), including a second receiver (420), a second Li-Fi receiver (430), and a second UI (410); And wherein the user-held device (300) is configured to: - When receiving a trigger command via the first UI (310), send a trigger signal from the first transmitter (320) to the remote device (400) for setting up the high-speed Li-Fi link (200); And the remote device (400) is configured to: - When receiving the trigger signal by the second receiver (420), provide a human-perceivable indication about a dedicated receiving area on the remote device (400) via the second UI (410) to assist in adjusting the position and / or orientation of the user-held device (300) so as to direct the Li-Fi transmitter (330) towards the dedicated receiving area; - Provide feedback on the alignment state between the Li-Fi transmitter (330) in the user-held device (300) and the dedicated receiving area; And the user-held device (300) is further configured to: - When the alignment state provided by the remote device (400) is determined to allow file transfer, or when receiving a start transmission command via the first UI (310), transfer a file from the Li-Fi transmitter (330) to the second Li-Fi receiver (430) in the remote device (400) via the high-speed Li-Fi link (200); and Wherein the trigger signal sent from the first transmitter (320) is via another link (500) different from the high-speed Li-Fi link (200), the another link (500) being based on at least one of an infrared link, a radio frequency link, and another optical link having a wider beam width than the high-speed Li-Fi link (200).

2. The system according to claim 1, wherein the first transmitter (320) and the second receiver (420) respectively have lower active power consumption than the Li-Fi transmitter (330) and the second Li-Fi receiver (430).

3. The system according to any one of the preceding claims, wherein the feedback from the remote device (400) further includes at least one of the following: - Instructions on the direction for adjusting the position and / or orientation of the user-held device (300); - Link quality information of the high-speed Li-Fi link (200); and - Suggestions for further improving the link quality; And the feedback is provided by: - directly via the second UI (410), or - via a feedback signal that is sent via the other link (500) to the user-held device (300) by a second transmitter (450) included in the remote device (400).

4. The system according to claim 3, wherein the remote device (400) is further configured to: - provide another feedback during or after the file transfer; and wherein the another feedback includes at least one of the following: the state that the transfer is in progress, the state that the transfer has been interrupted, the state that the transfer has been completed, link quality information, confirmation of file reception, confirmation of partial reception of a file, and negative confirmation of file reception.

5. The system according to any one of the preceding claims, wherein the user-held device (300) is further configured to: - turn on the Li-Fi transmitter (330) when the trigger command is received via the first UI (310); and - turn off the Li-Fi transmitter (330) after the file transfer to the remote device via the high-speed Li-Fi link (200) is completed, or is aborted by the user, or ends due to an interruption.

6. The system according to any one of the preceding claims, wherein the remote device (400) is further configured to: - turn on the second Li-Fi receiver (430) when the trigger signal is received; and - turn off the second Li-Fi receiver (430) after the file reception from the user-held device (300) via the high-speed Li-Fi link (200) is completed, or is aborted by the user, or ends due to an interruption, or a predefined timer expires.

7. The system according to any one of the preceding claims, wherein the user-held device (300) is further configured to: - highlight the projected transfer area by emitting a visible light beam to further assist in adjusting the position and / or orientation of the user-held device (300) so as to direct the Li-Fi transmitter (330) to the dedicated reception area on the remote device (400).

8. The system according to any one of the preceding claims, wherein the user-held device (300) further includes a Li-Fi receiver (340), the remote device (400) further includes a second Li-Fi transmitter (440), and the user-held device (300) is configured to: - send a second trigger signal from the first transmitter (320) to the remote device (400) when a second trigger command is received via the first UI (310) for setting up the high-speed Li-Fi link (200); and the remote device (400) is configured to: - When the second trigger signal is received by the second receiver (420), provide a human-perceivable indication regarding a dedicated transmission area on the remote device (400) via the second UI (410) to assist in adjusting the position and / or orientation of the device (300) held by the user so as to direct the Li-Fi receiver (340) towards the dedicated transmission area; and the device (300) held by the user is further configured to: - Evaluate the alignment state between the Li-Fi receiver (340) and the dedicated transmission area; - When the alignment state is determined to permit file transfer, or when a start reception command is received via the first UI (310), send a third trigger signal from the first transmitter (320) to the remote device (400) to initiate the high-speed Li-Fi link (200); And the remote device (400) is further configured to: - Upon receiving the third trigger signal, transfer a file from the second Li-Fi transmitter (440) to the Li-Fi receiver (340) via the high-speed Li-Fi link (200).

9. A device (300) held by a user for enabling high-speed file transfer to a remote device (400) via a high-speed Li-Fi link (200), the device (300) held by the user comprising: - A first user interface UI (310) configured to receive a trigger command; - A first transmitter (320) configured to send a trigger signal to the remote device (400) upon receiving the trigger command for setting up the high-speed Li-Fi link (200), wherein the remote device has a second user interface UI; - A Li-Fi transmitter (330) configured to transfer a file to a second Li-Fi receiver (430) in the remote device (400) via the high-speed Li-Fi link (200) when the alignment state between the Li-Fi transmitter (330) in the device (300) held by the user and a dedicated reception area on the remote device provided by the remote device (400) is determined to permit file transfer, or when a start transmission command is received via the first UI (310); and wherein the trigger signal sent from the first transmitter (320) is via another link (500) different from the high-speed Li-Fi link (200), the other link (500) being based on at least one of an infrared link, a radio frequency link, and another optical link having a beam width wider than that of the high-speed Li-Fi link (200); wherein a human-perceivable indication regarding the dedicated reception area via the second UI is provided by the remote device upon the remote device receiving the trigger signal to assist in adjusting the position and / or orientation of the device held by the user so as to direct the Li-Fi transmitter towards the dedicated reception area.

10. The user-held device (300) according to claim 9, wherein the user-held device (300) further comprises: - A first receiver (350) configured to receive feedback on the alignment state from the remote device (400) via the other link (500); - A controller (360) configured to determine whether the alignment state permits file transfer.

11. A remote device (400) for facilitating high-speed file reception from a user-held device (300) via a high-speed Li-Fi link (200), the remote device (400) comprising: - A second receiver (420) configured to receive a trigger signal from the user-held device (300) for setting up the high-speed Li-Fi link (200); - A second user interface UI (410) configured to provide a human-perceivable indication of a dedicated reception area on the remote device (400) upon receipt of the trigger signal; - A second Li-Fi receiver (430) configured to receive a file from a Li-Fi transmitter (330) in the user-held device (300) via the high-speed Li-Fi link (500); And wherein the remote device (400) is further configured to provide feedback on an alignment state between the Li-Fi transmitter (330) included in the user-held device (300) and the dedicated reception area; And wherein the trigger signal received by the second receiver (420) is via another link (500) different from the high-speed Li-Fi link (200), the another link (500) being based on at least one of an infrared link, a radio frequency link, and another optical link having a wider beam width than the high-speed Li-Fi link (200).

12. The remote device (400) according to claim 11, wherein the remote device (400) further comprises a second transmitter (450); and wherein the second transmitter (450) is configured to send feedback on the alignment state to the user-held device (300) via the other link (500).

13. A method (600) for a user-held device (300) to effect high-speed file transfer to a remote device (400) via a high-speed Li-Fi link (200), the method comprising - Receiving (S601) a trigger command via a first user interface UI (310); - Upon receipt of the trigger command, sending (S602) a trigger signal from a first transmitter (320) to the remote device (400) for setting up the high-speed Li-Fi link (200), wherein the remote device has a second user interface UI; - When the alignment state between the Li-Fi transmitter (330) in the device (300) held by the user and the dedicated receiving area on the remote device provided by the remote device (400) is determined (S603) to permit file transfer, or when a start transmission command is received (S604) via the first UI (310), transfer (S605) the file from the Li-Fi transmitter (330) to the second Li-Fi receiver (430) in the remote device (400) via the high-speed Li-Fi link (200), and wherein the trigger signal transmitted from the first transmitter (320) is via another link (500) different from the high-speed Li-Fi link (200), the another link (500) being based on at least one of an infrared link, a radio frequency link, and another optical link having a beam width wider than that of the high-speed Li-Fi link (200); wherein a human-perceivable indication regarding the dedicated receiving area via the second UI is provided by the remote device when the remote device receives the trigger signal to assist in adjusting the position and / or orientation of the device held by the user so as to direct the Li-Fi transmitter towards the dedicated receiving area.

14. A method (700) for a remote device (400) to adapt to high-speed file reception from a device (300) held by a user via a high-speed Li-Fi link (200), the method comprising: - Receiving (S701) by a second receiver (420) a trigger signal from the device (300) held by the user for setting up the high-speed Li-Fi link (200); - Providing (S702) via a second user interface UI (410) a human-perceivable indication regarding a dedicated receiving area on the remote device (400) when the trigger signal is received; - Providing (S703) feedback regarding the alignment state between the Li-Fi transmitter (330) included in the device (300) held by the user and the dedicated receiving area; - Receiving (S704) by a second Li-Fi receiver (430) the file from the Li-Fi transmitter (330) via the high-speed Li-Fi link (200); and wherein the trigger signal received by the second receiver (420) is via another link (500) different from the high-speed Li-Fi link (200), the another link (500) being based on at least one of an infrared link, a radio frequency link, and another optical link having a beam width wider than that of the high-speed Li-Fi link (200).

15. A computer program product comprising a computer program which, when executed by a device (300) held by a user each including a processing device and a remote device (400), causes the processing device included in the device (300) held by the user to implement the method according to claim 13 and causes the processing device included in the remote device (400) to implement the method according to claim 14.

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